As a retired mech engineer I would love to get you down the pub for a few discussions and some pints. Love your channel fella, it's rare to see such understanding nowadays as most of what I hear is crap. I'm in my sixties and ride a Kawasaki Z1000SX. Much respect Matt.
Harley-Davidson produced a scooter called the "Topper" with a 165cc 2t engine and CVT back in the late '50s or early '60s. It was quite a performer, very sustainable little vehicle but crude compared to the Italian products.
I think there is also a bit of marketing involved in the lack of CVT's being used. Much like F1 banning them, their excuse was they didn't think viewers would like the droning engine sound created by the use of CVT's.
Honda Civic has engineered simulated "gears" into their CVT. When in paddle shift mode the steps or gears simply locks the torque converter into a fixed position, it releases as the paddle is actuated. It works quite well.
Dan Henderson It is slower than having a fixed RPM though. Nissan Skyline Sedan 350gt-8 and Nissan Juke do this as well, quite useless as reviews have gone.
Interesting discussion. CVT's are getting better and more common all the time. Even on fairly high power >260HP (Subaru WRX STI). Eventually I believe they will surpass transmissions with gear teeth. BTW I think you drawings are awesome, especially considering how quickly you do them.
I came across a cvt gearbox at work on a slitting machine and the transmission was a segmented chain with the usual expanding pulleys but the chain was pushed not pulled through a guide. Because it had chain segments and teeth on the pulleys it was non slip.
ATVs and side-by-sides use CVTs... they can get the power down.. no issues up and over 200hp on big turbo builds. Only concern is cooling. Needs lots of air to stay reliable. Many cars now do, too.
I have to correct Matt here at the end. CVTs (of scooters at least) rely on the locking of the belt between the pulley sides. The Friction of the V shaped Belt Pulled HARD between the V shaped pulley faces is what grants you traction. The belt itself is a simple woven material, i don't think they actually even use glass fiber for everyday use belts; kevlar only on expensive replacements. What actually grant you traction is the rubber compund molded around the belt that gets squeezed between the pulleys. Why is the belt toothed? Because it increases the surface area of the rubber material while at the same time giving it enough flex to be able to bend around the pulleys. All of this to say that friction on the sides of the belt is the only thing giving you traction. The ultimate working then of the scooter CVT is given by the rollers pushing the variator to slide (squeezing the belt); the variator spring usually on the real pulleys works against the variator (again squeezing the belt) and then the real pulleys opens on a set of cammes. Those cammes are angled to further increase the work the variator has to do to increase the transmission ratio. On top of that the rear pulleys rotates (due to the cammes) in the OPPOSITE direction of the rotation direction needing thus to overcome the load and friction of the belt in order to being able to open. This prevents a sudden change of ''gearing ratio''. The italian translation of the rear pulleys assembly is ''Torque corrector'' instead of the english ''Torque Converter''. Corrector in my opinion is more explanatory and true as a definition. As the rear pulley opening in the opposite direction as to which the belt is pulling is responsible of auto-correcting the resistance the rear pulleys pose to the variator. The more the variator tries to increase the ratio, the more friction the torque converter has to overcome in sliding against the belt and this is extremely important at high throttle openings and high loads; meaning the engine is kept at a lower trasmission ratio and thus high rpms. As the throttle is closed and or the load is decreased the variator is pulling the belt with less force and so the torque converter has less friction to overcome and is free to increase the transmission ratio faster.
IMO if they were to make a CVT capable of holding up to the power output and traction available on a superbike, it would need to be at least as big/sturdy as a typical snowmobile CVT setup, which is absolutely massive. And even those things still have issues with tearing belts sometimes. In order to fit that sort of pig of a CVT into your frame, it would take up at least half the space longitudinally speaking in your frame. You could maybe use some sort of narrow V-twin in place of a straight 4, but it may end up being unbalanced because your engine is on one side but your CVT is on the other and they do not weigh the same.
I'd honestly like to try and build a hydraulic CVT. Use some plunger pumps and plunger style motors. If on a car use one big ass pump on the engine and four smaller ones for the wheels! Yeah it would be expensive as hell but the durability would be supreme! Also you could build a pressure accumulator under your car to fill with pressurized fluid when you brake. Run the motors in reverse and fill up that accumulator to slow the car down. Think of the accumulator as a bottle having a piston in it with a spring or a high pressure gas on the other side. Pumping in the fluid would compress the gas and store your energy. Then use it to get your car moving again when you put your pedal to the floor. You'd save even more power!
I've often wondered what it would be like if someone did something mad with gearing Ike combining CVT and magnetic gearing technology. I know it is far fetched, but non-physical coupling would solve lots of problems. It is just me being a bit mental, but sometimes it is good to think outside of the box.
My thought about improving the limited torque transference is that instead of having the sides contracting and expanding, couldn't they make a barrel that expands and contacts on the underside of the belt (something akin to an exhaust pipe expander)? It would make for a much larger contact patch.
sadly on a bike the size and mass would not quite be perfect, but other than pure mechanical means of gears and chains we do have 2 more options. one of them is hydraulics, variable hydraulic motors do indeed exsists. and electric generator->inverter->electric engine combo is allso sortha an option to some degree.
Quite simply, Gears are more efficient (88-92%, depending on design spec, vs 80-84% for CVT), and have a faster "sweep" (lowest to highest ratio and back), and scale with less volume (size) and mass (weight) at superbike power levels. Most CVTs work great in low torque applications (scooters), but don't scale well with added torque. Even though the loss in efficiency is mostly recovered via constant peak input, you still have to obtain the sweep time... with requires more powerful controls and induces more inefficiency through friction. To obtain a competitive sweep time to that of a gearbox, would basically require the equivalent of a CVT from a Nissan Maxima. Now vision two bikes... one with a traditional gearbox, and one with the CVT from a Nissan Maxima. which one would you rather fling around at superbike speeds? There's far more to Superbikes than just going fast, or getting power to the wheels... you have to transfer that power to the ground at progressive lean angles, AND have bike capable of being nimble. Basically, power is important... but packaging is CRUCIAL. Hence, why superbikes aren't running around the track with V12 F1 engines, CVTs, or 700mm tires.
Old School Triumph T-140 Hill climber burning Methanol & Nitromethane .. I had two friends who were Pro Hill climbers one had a Norton the other had a BSA . They were both Motorcycle mechanics by trade . One was a Honda / BMW mechanic before he started his own shop .. The other repaired British bikes.. I worked in his shop one summer when I was 16 years old .. His winter business was building Mole traps .. These Hill climbers were hard tails .. My friend had just purchased a brand new Yamaha TT 500 to build a Hill climber out of He was doing a plug check on a two lane road it started raining hard.. A little old lady pulled to the side of the road ahead of him .. When he went to pass her she pulled a U turn in front of him .. He broke his leg in 7 places after a month in the Hospital he never built the TT 500 Hill climber.. A little Old lady did the same thing to me in her Cadillac .. in a curvy section with blind curves .. I like to go fast though curves in my GYT Kit Yamaha 80 .. I stood the bike on the front wheel but stopped before hitting her I turned parallel to her car and kicked a big dent in her rear door to get her . attention .. czcams.com/video/uyoa3wqguP8/video.html
My mom's toyota hylander hybrid awd has a CVT I just found out today, 268hp with a cvt, electric motors for instant torque, and all that power on all 4 wheels, the thing is fantastic!
Very nice video, dissecting everything to bits, but what about hydrostatic CVT? Much like small lawn mowers(or so I've heard) and Fendt, a tractor company uses. Essentially it's using two(or more, but let's go with two for simplicitys sake) varible hyrdaulic pumps sort to speak, however one is used as a pump and the other as a motor. The pump is driven by the engine and the motor is driven hydraulicalby by the pump. These systems aren't definetly limited by engine torque, because the most powerful tractor using this system (Fendt 1050) has 2400 Nm. It's ability to vary the productivity of both pumps is very similar to the belt/chain driven CVT. It can be electriaccly controlled and can be used both ways(forward and reverse), however this would be useless on motorcycles. I do understand that one of the downsides for motorcycles is definetly it's size, but I haven't heard of it even in the automotive industry. Why is that?
Old vid sorry. But you're a great teacher and an interesting topic. You didn't explain (or I didn't understand) what the mechanism is by which the bike gets the gear ratio right on naturally. I mean you don't select the gear as it's one continuously changing gear. What makes it change the ratio to stick to the same rpm regardless of bike speed? I had this idea a while back of some kind of CVT where the gear sprocket would effectively open up as vehicle speed increases by way of centrifugal force enlarging the diameter by some kind of calibrated...spokes with pinned roller ends, that allow the thong to enlarge or contract to suit the speed. Does that make any sense? And could it be a possibility?
a CVT Superbike is going to be unbeatable no question. but the downside is you can't have fun being stuck in a certain rpm it's sort of like you're stuck in 6th gear and you're just feathering the clutch until the engine can manage it. if you ride a Scooter you probably know what im talking about
the belt itself is somewhat in multiple gears at once. the inside of the belt rubbing on the variator wall is smaller diameter than the outside of the belt. the only way to escape that is by things slipping and rubbing. its a bit like wide car tires. from one side of the car to the other you have a differential but what about from the inside edge of the tire to the outside edge eh? something has to give, and it does, with heat and wear in return. small scooters with small torque and small belts have much more efficient drives than larger due to this. And they already overdrive the belt, with reduction in the hub so the cvt itself sees more rpm and therefore less torque. similarly many bikes overdrive the clutch and transmission at higher rpms and get the torque back from the final drive so they can carry lighter gears and clutch. a benifit you touched on in the fact that 5 out of 6 gears are dead weight while the machine is in operation. parabolic wheel cvt's aren't a heck of a lot better either in theory or practice and the all steel belts are mainly just a material advancement. some systems (Nissan juke I think) run basically a gang of a few small cvt's so they can handle bigger torque with minimal loss all at the cost of compexity.
I avoid any kind of automatic transmission,because i like shifting the gears myself.the thing with CVT's in cars is there using them for gas mileage not power delivery.i don't ride scooters or snowmobiles,but i think there are more set up for power range.with a manual i can do both.I'm sure someone is working on this problem.that is going to make it more complex expensive and bigger.I like the simple solution,drive a manual.
electric engine stering cvt position like in burgman 650 plos some engine with constant power dont even need this just wide peak power at 100% throtle open from let say 2000 to 6000 rpm and you have both .
In one of Hub Nut's U-Tube videos he changes the CVT belt on his restored Invacar project and demonstrates it in action during testing. He points out that the engine the largest capacity used with a CVT and is stretching CVT transmission to its limits. Belt wear belts out far faster than oil filled gearboxes do gears. The more torque put through them, the shorter the service life. Then there is the squealing that a worn CVT belt makes to contend with.....
Because for snowmobiles size isn't a massive constraint, and slip in the system isn't that much of an issue in regards to the track and all its components. A motorbike gearbox is compact and it works, with no slip.
My CVT belt isn't square. The upper section - yes, but the section that bends is curved for the ramp angle. It is out of spec with more than 1mm of wear. My belt was replaced recently and it is double ribbed. Typical belts only have ribs facing away from the casing.
My snomobile is a 1300cc turbo triple 4stroke it makes 250hp i dont know the torque? but i would say its more about mass and space(lack of space)on a slim bike then slipage?Cost also! Good cvt’s that take all the torque you want cost alot!! And take’s up lots of space
indeed... and cvts have losses too... and you need some controll mechanism, you see for fuel economy you may not want to keep the engine running at the rpm where it produces the highest power figure, not to mention engine longitivity... sometimes you would need to keep the enigne at an rpm where its most efficient..
What we must all realize is it's horses for you know what I have a Mana great bike but don't think its an R1 or an R6 and for that matter don't think it's a Vespa It's a bike with auto gearbox Great if you have one arm or are old like me or just like riding bikes and not scooters it's great infact more than great its a bloody good bike great for touring or knocking about town The gearbox/auto belt works fine I will never get rid of mine no matter what other's say its good fun and most important IT AIN'T A FUCKING SCOOTER OK !!!!!!!!!!!!! Matt as always does a great job of explaining what things are so well done Matty now you can carry on !!!!!!!!!!!!!
Cvt in scooters have came a long way watch zip stunter he has he hp 2 stroke builds I'm talking 30 horse power and he tunes them great they dont loose as much power as you think they would in scooters
Audi had the Multitronic in their diesel (and petrol) cars, mostly in the A6 if I remember correctly. On the diesels at full throttle it just ran at 4500rpm the whole time, kinda cool. Sounds shitty anyway so it was alright. But if you google gearbox failures multitronic you probably know what mechanics think about that thing. The 7-speed DSG (double clutch) just absolutely fucked the cvt transmission, luckily.
CVTs are awsome. But i still like the sound of gear shifts. Listen to the experimental CVT F1 car some time. It sounds surreal. Just a constant whine at one specific frequenzy all The way. Awsome... But wierd. Love my scooter tho.
One Newton-Meter used to be equal to one Joule, which was the amount of work done if an apple that fell one meter onto your face while you were trying to sleep under an apple tree. It's a very small amount, but annoying nonetheless. Now we use Newton-Meters for torque because nobody really believes that Newton got hit by an apple. Some of this might be true. But I doubt it.
All friction based CVT designs suffer from limited torque capacity before the drive slips, but with a V belt design the belt wedges itself harder into the pulleys as more torque is applied, which boosts torque capacity (but also ruins efficiency). The toroidal CVT doesn't have this action, so torque capacity is a problem. Nissan developed their Extroid CVT transmission ~20 years back with uses a toroidal design, and uses a special transmission fluid to transmit the torque between the rollers rather then mechanical friction but they were still unreliable, and their latest CVT now uses expanding pulleys and a steel belt as do virtually all the other automotive manufacturers CVTs.
a question the Gilera gp800 uses a cvt transmission with 73nm of torque. would it not possible then to use a cvt on a 600 sportbike (torque around 70nm)? but with cvt You always ride on your max power and not torque. maybe that's the answer?
There are plenty of snowmobiles, atv's and utv's that are high horsepower machines using CTV. Many sleds that come from the factory with over 200 horsepower.
@@dirtygarageguy You would be surprised on how well they hook up. Especially on a picked track in low snow or icy conditions. There are plenty of sleds that weigh less than 550 lbs making 160-170 hp and 110 ft/lbs of torque bone stock. As for UTV's, I'll give an example. A Polaris RZR 1000 turbo side-by-side weighs about 740 lbs and makes 168 hp/114 ft/lbs of torque. No where in the manual do they suggest not riding in high traction conditions. You can buy one with awd if you want. If the belts can handle those machines, I'm sure they would be fine on a bike. You are comparing scooter/low hp setups against traditional gear boxes. Check out Skidoo's PDrive cvt system. You might be surprised how much effort snowmobile/atv companies put into making CVT's handle the big hp engines of modern snowmobiles, utv's and atvs.
Belt drives are very inefficient compared to gears. Snowmobiles use them because they have to have constant power to the track. Shifting gears in two feet of snow at wide open throttle won't work on a snowmobile. Why use a belt CVT on a motorcycle when it will result in significantly less horsepower getting to the rear wheel? As for horsepower limits, the old 1000cc Thundercats from the 1990s had 172 HP stock. Standard HP for an 800cc two stroke snowmobile these days is 160 HP. And as others have said, lots of two stroke snowmobiles with turbochargers have over 300 HP through a belt CVT.
A good example is with an old snowmobile lift up the rear give it gas watch the belt just like the gearing on a motorcycle sprockets down in the rear up in the front the faster you go
if Nissan could develop a CVT for a 3.5L v6 which, in the Maxima atleast, produces 371Nm (274lb/ft) why won't it work on a sport bike? Would it be engineered too big for such an application?
That and the drone. it gets so annoying. that's the real reason they haven't taken off in the automotive scene. that and their rubber-band like throttle response.
I saw on TV recently here in the US there is small a small City Style car that uses a two single cone style CVT transmission but I've only seen a few commercials for it and that was two or three years ago maybe you've seen it maybe you can let us know what the deal is with it
Sorry I just started watching your Channel yesterday I keep forgetting that it's a bike Channel not a car Channel or a mechanic Channel and I do like your input on the different things that you noted but from an engineering aspect I would like to know your thoughts on these types of cars are the size limitations and whatnot of the CVT
What's the torque limit for a scooter CVT with roller weights/torque spring & centrifugal clutch? As in when the drive pulley is accelerating too fast for the belt to grip
So explain the Apriia Mana 850 GT which of course comes with a CVT transmission "www.webbikeworld.com/motorcycle-reviews/aprilia-mana-850-gt/" ?? Seriously ??
I'm so happy you've mentioned the Aprillia. 1 - It has gears for one, a 7 speed planetary gearbox after the CVT output. Hence why you can select gears manually. 2- the thing is massive and weighs double that of a standard 6 up gearbox 3 - 840cc and it puts out 55hp at the rear wheel? And you wanna stick that on a R1 with 190HP? Give me a break 4 - Put Aprilia mana 850 problems into google and all you'll see if gearbox/CVT problems. 5 - R1 = 99Nm torque Mana 850 = 54Nm just less than half 6 - God knows what it costs, but 32 electric motors, 2 worms drives, 19 gears in the gearbox, and electronics package 7 - the bike weighs 234 Kgs that's 35 more than the R1 8 - Aprillia pulled it from production in 2011 becasue of all the warranty claims. Sound like a good idea? And yes I'm being serious.
Except you are wrong again: ---- ------ "sparts.aprilia.it/Marche/apr/Cataloghi/400700/400700_46.gif" One final FIXED reduction gear after the CVT. You can see the output sprocket. The 7 speeds are computer assigned ratios for the drum to ease veteran rider transition. The Honda is (and was in the 70's) an automatic shifting transmission. Aprilia is not it is a CVT.
"sparts.aprilia.it/Marche/apr/Cataloghi/400700/400700_46.gif" not talk just facts. It has no changing gears. fact Does it suck? absolutely I would ever own one but the fact is they made one and it is a viable product. Jay Leno drove it.
Very true, and my bad. I read an article way back 10 years+ ago when Aprilia were hinting at what they were doing. It stated that from interviews at a bike show that they were working on a CVT and planetry gearbox arrangement with 7 to 8 gears. I emailed a friend today who worked at Ducati and he told me they opted out of that design because of costing. They had to back down the power and use an electronics guide rail to give the sense of 7 gears, by picking 7 ratios of the CVT. Totally caught me out there dude. My fault on that one.
You are incorrect. CVT are meant to be run at a constant RPM at peak HP. The step you show is a compromise the auto use because the drivers dislike the sound of a constant rpm engine.
WTF are you talking about? How the fuck is a vehicle with a CVT meant to run at constant rpm/velocity? You do know that we have brakes and speed limits? You really are an idiot. Usually I not this hard but you have missed the point of transmissions full stop. And starting with; "You are incorrect." means what? Go on genius - what the fuck are you talking about? As a vehicles speed increases the ratio required is different due to the drag experienced at different speeds. Have you heard of acceleration?
This is whats said on the physics of a CVT belt drive. Maybe constant RPM is confusing. The constant RPM fluctuates within the powerband. Picture a snowmobile ((all CVT) they only engage when the revs reach the powerband. BTW your name calling only proves who the idiot is here. You don't need to stoop to such a lowbrow monologue to make a point.
Totally unfamiliar with CVT even though I started on and rode scooters years ago. I've moved on a very long way since then mechanically but not got an inkling on this LOL. Understood the principle though and would love to see this as some sort of CVT tear down on an actual system.
As petri said. CVT's can be used on pretty much everything and have. Size and weight of a system that could handle the torque is the main issue. There will be a follow up video coming soon - matt
That is to true.. you can fidle with everything in car, cos any ways there is like 5-7 bikes worth of mass.. Still when you think about it, I don't think it would be good to drive. There is no sens of feeling in that one. CVT just goes and goes and goes. Loosing sens of speed would be so easy.. I don't think I would like it more then an automatic transmission.
@@dirtygarageguy So how do we expain these snowmobiles that are making hundreds of hp, and running close to 250 mph in 1000ft? They're not that big or heavy, and every single one uses a cvt.
@@DistinctOgre Look at bikes with snowmobile engines, they are very wide and large. Sure you can re-design it for a bike but they would still be much larger than a normal gearbox.
Great video. I think leyland made a car with a cvt in the 70's it did 60mph forwards and 60mph backwards. Have they every done a motorcycle or car with a hydrostatic gearbox like mini diggers & mowers have? I guess hydro are heavy over heat and don't make too much top speed. I also was told they sap about 15% of power from engine.
" I also was told they sap about 15% of power from engine." - alot of transmissions designs so, friction, sound, heat etc All this energy has to come from somewhere
Interesting discussion about why not CVT usually occurs on motorcycles. I think you miss some of the arguments against CVT. Owned a turbocharged snowmobile, Yamaha Nyro with 270 hp. Must say that the CVT on this machine had good reliability. The belt could handle this power very good. In theory, CVT should be a good option despite poor efficiency. The problem with CVT on this powerful snowmobile was that the clutch had to have heavy weights in order not to overrev. This causes the CVT to gear up very quickly, which in turn gives a poor driving feel and poor response. On motorcycles, I think most riders want to control the rpm and torque themselves, something that only a transmission can offer. That gives simply a better riding experience, expecially in corners, breaking,different riding conditions and speeds . A bit like why most racing cars do not have an automatic gearbox. Maybe CVT is a excelent choise on a dragbike?
I don't know too much of snowmobiles or engineering but my suppose is that the snowmobile track will break traction from the ground and slip easier than the CVT will overcome friction between the band, while with a road bike the cvt will break traction and slip from the band before the tyre will break traction from the ground. It's just my guess since it always seems there is some degree of tyre slip on dirt I'm guessing there is some on snow as well. Maybe since snowmobiles seem a bit wider and heavier than bikes the transmission can be reinforced more and still meet a good performing weight and so the CVT could handle it. I don't really know honestly just my thought, I'm sure production costs and competing sale price come into the choice of selling a bike with a proven transmission that works well or a more expensive but slightly better performing one while risking losing the feel of shifting gears a lot of bike owners probably would sorely miss if they move to a CVT.
For their size they should do, and there's also alot of traction losses, that and the cold weather is why they are used. Try fitting a skidoo CVT in a superbike.
The only times I've experienced excessive belt slippage on a snowmobile is when the engine isn't torquey enough and it pulls a load that is to heavy for the engine. That is why work sleds often have low gear and mechanical reverse. Slippage can also be an issue if the belt or cvt is worn out. Snowmobiles usually don't get very high mileage. So the snowmobile cvt is mostly made out of aluminum.
Rokon Motocross Bike they were competitive .. and got a Bronze Medal in an Italian ISD race www.off-road.com/dirtbike/tech/vintage-dirt-bikes-a-look-at-rokon-automatics-53152.html
What about the hydraulic torque converter developed by Koenigsegg for the Regera? It is around 8 or 10kg i think and can handle 1500hp. No gearbox on that car.
Christian himself explains that if you eliminate all electrical propulsion the car will do 0-60mph in 4 seconds. I'm sure I might be missing something but it's still an engine with a powerband. I don't see how this techonolgy couldn't be adapted to motorcycles. Their camless technology too.
"Their camless technology too." you mean Freevalve which hasn't been implemented yet. "I'm sure I might be missing something but it's still an engine with a powerband." - I don't understand what you mean by this?
I mean it's a relatively normal engine, capable of 0-60 in 4s with that torque converter without the help of electrical motors. I know I might not see all the details as weight and power of the car play a big role but it seems achievable in a motorcycle, not with that extreme performance but at least usable in daily riding conditions.
"I mean it's a relatively normal engine, capable of 0-60 in 4s with that torque converter without the help of electrical motors." - Normal?!!!! - A twin-turbocharged V8 engine with a 5.0-litre capacity. It produces 820 kW (1,115 PS; 1,100 hp) at 7,800 rpm and 1,280 N·m (944 lb·ft) at 4,100 rpm. Would you call that normal. The car can accelerate with just a 2.73:1 reduction because the engine produces 1,280 Nm of torque @ 4,100rpm. That's 600 Nm @ 2,000 rpm. Of course it can pull away that fast. I also found what the batteries and motors weigh - "Koenigsegg reported that the omission of a gearbox and addition of electric motors and battery only added 88 kg (194 lb) compared to what the Regera would have weighed with the same combustion engine but a 7-speed dual-clutch transmission (DCT) and no electric motors or batteries." - only added 88kgs - ONLY lol
I love the Idea of cvt can you remember the Dafs and the volvos czcams.com/video/R8AzqtomwD0/video.html I also like the new Keorneseggggchgegv (word salad swedish Supercar) although that's just a final drive and a torque converter. F1 has toyed with the idea over the years to little success. The only usable and drivable linear torque curve is from electric sadly and nobody wants that shit.
The Workshop every snowmobile uses a "variator drive" No slipping if adjusted correctly. not even when driving in water, where traction is extremely good. bad if it becomes too wett. not fuel efficient at al, on anything that moves somewhat easy. thats where the real issues starts for variator drive on a bike. the unabillity to coast at low RPM at a high speed. say you have variator to activate at 3000 RPM. then you have to constantly keep engine above 3000 RPM to not lose momentum. work's great on something that constantly need to have momentum. in deep snow. in sand. uphill. etc.
"The Workshop every snowmobile uses a "variator drive" No slipping if adjusted correctly. not even when driving in water, where traction is extremely good." Its called a CVT Continously variable transmission. And yes it does slip when you try and stick 200-300HP down it. This why this type (belt type) is not used in cars etc.
The Workshop well.. in Sweden the system used in snowmobiles and other wehicles, is called a variator. there is no slip in a snowmobile. if adjusted properly. Volvo used it in a car..
The Workshop do a search on youtube.. Mountain machine turbocharged. snowmobiles on water in Sweden. why not just check out criss burandt. and ask him if his snowmobiles slip? 200-300hp with fullzise track's, 100 cm paddles..
Here is a good Video of a Christini two wheel drive they are like $9,000 very reasonable Yamaha built a two wheel drive WR-450 with Olin hydraulic drive and sold it for $24,000 czcams.com/video/si-bI84SZKA/video.html
As a retired mech engineer I would love to get you down the pub for a few discussions and some pints. Love your channel fella, it's rare to see such understanding nowadays as most of what I hear is crap. I'm in my sixties and ride a Kawasaki Z1000SX. Much respect Matt.
Colin M sweet bike m8
This question was on my mind the whole day as i was riding a 125cc CVT scooter.
Harley-Davidson produced a scooter called the "Topper" with a 165cc 2t engine and CVT back in the late '50s or early '60s. It was quite a performer, very sustainable little vehicle but crude compared to the Italian products.
This reminded me of when my dad and I replaced a torque converter in his truck.
Why don't bikes use torque converters instead of cvt's?
Torque converters are akin to a clutch not a transmission
@@dirtygarageguy oh.
Thanks!
I think there is also a bit of marketing involved in the lack of CVT's being used. Much like F1 banning them, their excuse was they didn't think viewers would like the droning engine sound created by the use of CVT's.
I like how you explain things. You have the gift of picking the shortest path to your audience's minds. ;)
This channel is incredibly underrated and undersubscribed
Cheers dude - matt
Great video. Technical but understandable due to your knowledge and teaching ability.
cheers for the comment dude - matt
ginganz13 You should probably just stick to Dellboys channel...........
Gosh, what an excellent teacher you are. thanks ! I'm subscribing !
Cheers dude
Honda Civic has engineered simulated "gears" into their CVT. When in paddle shift mode the steps or gears simply locks the torque converter into a fixed position, it releases as the paddle is actuated. It works quite well.
Dan Henderson It is slower than having a fixed RPM though. Nissan Skyline Sedan 350gt-8 and Nissan Juke do this as well, quite useless as reviews have gone.
Interesting discussion. CVT's are getting better and more common all the time. Even on fairly high power >260HP (Subaru WRX STI). Eventually I believe they will surpass transmissions with gear teeth. BTW I think you drawings are awesome, especially considering how quickly you do them.
You have MAD freehand drawing skills 😂 I watched your 1 stroke engine video and this man spit out a whole engine design in like 3 seconds of drawing!
lol - cheers dude
I came across a cvt gearbox at work on a slitting machine and the transmission was a segmented chain with the usual expanding pulleys but the chain was pushed not pulled through a guide. Because it had chain segments and teeth on the pulleys it was non slip.
Cvt's are great, especially on small off road bikes and quads and buggys for learners there's no easier way to keep the performance and ease of use
ATVs and side-by-sides use CVTs... they can get the power down.. no issues up and over 200hp on big turbo builds. Only concern is cooling. Needs lots of air to stay reliable. Many cars now do, too.
Also another great point - CVT cooling - will need its own video - cheers matt
I have to correct Matt here at the end. CVTs (of scooters at least) rely on the locking of the belt between the pulley sides. The Friction of the V shaped Belt Pulled HARD between the V shaped pulley faces is what grants you traction. The belt itself is a simple woven material, i don't think they actually even use glass fiber for everyday use belts; kevlar only on expensive replacements. What actually grant you traction is the rubber compund molded around the belt that gets squeezed between the pulleys. Why is the belt toothed? Because it increases the surface area of the rubber material while at the same time giving it enough flex to be able to bend around the pulleys. All of this to say that friction on the sides of the belt is the only thing giving you traction. The ultimate working then of the scooter CVT is given by the rollers pushing the variator to slide (squeezing the belt); the variator spring usually on the real pulleys works against the variator (again squeezing the belt) and then the real pulleys opens on a set of cammes. Those cammes are angled to further increase the work the variator has to do to increase the transmission ratio. On top of that the rear pulleys rotates (due to the cammes) in the OPPOSITE direction of the rotation direction needing thus to overcome the load and friction of the belt in order to being able to open. This prevents a sudden change of ''gearing ratio''. The italian translation of the rear pulleys assembly is ''Torque corrector'' instead of the english ''Torque Converter''. Corrector in my opinion is more explanatory and true as a definition. As the rear pulley opening in the opposite direction as to which the belt is pulling is responsible of auto-correcting the resistance the rear pulleys pose to the variator. The more the variator tries to increase the ratio, the more friction the torque converter has to overcome in sliding against the belt and this is extremely important at high throttle openings and high loads; meaning the engine is kept at a lower trasmission ratio and thus high rpms. As the throttle is closed and or the load is decreased the variator is pulling the belt with less force and so the torque converter has less friction to overcome and is free to increase the transmission ratio faster.
Dont you mean reduces surface area.
IMO if they were to make a CVT capable of holding up to the power output and traction available on a superbike, it would need to be at least as big/sturdy as a typical snowmobile CVT setup, which is absolutely massive. And even those things still have issues with tearing belts sometimes. In order to fit that sort of pig of a CVT into your frame, it would take up at least half the space longitudinally speaking in your frame. You could maybe use some sort of narrow V-twin in place of a straight 4, but it may end up being unbalanced because your engine is on one side but your CVT is on the other and they do not weigh the same.
Toyota has made some pretty good CVTs now. I hope there will be a way to implement them.
me and my newborn is watching this he dont want to sleep, " hes 4 days old " got to start with them early :) good vid by the way
Congrats dude, and thankd for the great comment - matt
lol
I'd honestly like to try and build a hydraulic CVT. Use some plunger pumps and plunger style motors. If on a car use one big ass pump on the engine and four smaller ones for the wheels! Yeah it would be expensive as hell but the durability would be supreme! Also you could build a pressure accumulator under your car to fill with pressurized fluid when you brake. Run the motors in reverse and fill up that accumulator to slow the car down. Think of the accumulator as a bottle having a piston in it with a spring or a high pressure gas on the other side. Pumping in the fluid would compress the gas and store your energy. Then use it to get your car moving again when you put your pedal to the floor. You'd save even more power!
I've often wondered what it would be like if someone did something mad with gearing Ike combining CVT and magnetic gearing technology. I know it is far fetched, but non-physical coupling would solve lots of problems. It is just me being a bit mental, but sometimes it is good to think outside of the box.
Definately, but it is a bit too mad lol
I switched from 50cc cvt scooter to a manual 72cc motorbike, and thank fucking God I dont need to listen to that horrible constant rpm drone anymore
My thought about improving the limited torque transference is that instead of having the sides contracting and expanding, couldn't they make a barrel that expands and contacts on the underside of the belt (something akin to an exhaust pipe expander)? It would make for a much larger contact patch.
sadly on a bike the size and mass would not quite be perfect, but other than pure mechanical means of gears and chains we do have 2 more options. one of them is hydraulics, variable hydraulic motors do indeed exsists. and electric generator->inverter->electric engine combo is allso sortha an option to some degree.
Quite simply,
Gears are more efficient (88-92%, depending on design spec, vs 80-84% for CVT), and have a faster "sweep" (lowest to highest ratio and back), and scale with less volume (size) and mass (weight) at superbike power levels.
Most CVTs work great in low torque applications (scooters), but don't scale well with added torque. Even though the loss in efficiency is mostly recovered via constant peak input, you still have to obtain the sweep time... with requires more powerful controls and induces more inefficiency through friction. To obtain a competitive sweep time to that of a gearbox, would basically require the equivalent of a CVT from a Nissan Maxima.
Now vision two bikes... one with a traditional gearbox, and one with the CVT from a Nissan Maxima. which one would you rather fling around at superbike speeds?
There's far more to Superbikes than just going fast, or getting power to the wheels... you have to transfer that power to the ground at progressive lean angles, AND have bike capable of being nimble.
Basically, power is important... but packaging is CRUCIAL. Hence, why superbikes aren't running around the track with V12 F1 engines, CVTs, or 700mm tires.
Old School Triumph T-140 Hill climber burning Methanol & Nitromethane .. I had two friends who were Pro Hill climbers one had a Norton the other had a BSA . They were both Motorcycle mechanics by trade . One was a Honda / BMW mechanic before he started his own shop .. The other repaired British bikes.. I worked in his shop one summer when I was 16 years old ..
His winter business was building Mole traps .. These Hill climbers were hard tails .. My friend had just purchased a brand new Yamaha TT 500 to build a Hill climber out of He was doing a plug check on a two lane road it started raining hard.. A little old lady pulled to the side of the road ahead of him .. When he went to pass her she pulled a U turn in front of him .. He broke his leg in 7 places after a month in the Hospital he never built the TT 500 Hill climber.. A little Old lady did the same thing to me in her Cadillac .. in a curvy section with blind curves .. I like to go fast though curves in my GYT Kit Yamaha 80 .. I stood the bike on the front wheel but stopped before hitting her I turned parallel to her car and kicked a big dent in her rear door to get her .
attention .. czcams.com/video/uyoa3wqguP8/video.html
My mom's toyota hylander hybrid awd has a CVT I just found out today, 268hp with a cvt, electric motors for instant torque, and all that power on all 4 wheels, the thing is fantastic!
You really do a great job of explaining. I would like to see some bike producer use a D-drive.
Very nice video, dissecting everything to bits, but what about hydrostatic CVT? Much like small lawn mowers(or so I've heard) and Fendt, a tractor company uses. Essentially it's using two(or more, but let's go with two for simplicitys sake) varible hyrdaulic pumps sort to speak, however one is used as a pump and the other as a motor. The pump is driven by the engine and the motor is driven hydraulicalby by the pump. These systems aren't definetly limited by engine torque, because the most powerful tractor using this system (Fendt 1050) has 2400 Nm. It's ability to vary the productivity of both pumps is very similar to the belt/chain driven CVT. It can be electriaccly controlled and can be used both ways(forward and reverse), however this would be useless on motorcycles.
I do understand that one of the downsides for motorcycles is definetly it's size, but I haven't heard of it even in the automotive industry. Why is that?
There will be a follow up to this video, based on other designs etc - matt
Old vid sorry. But you're a great teacher and an interesting topic. You didn't explain (or I didn't understand) what the mechanism is by which the bike gets the gear ratio right on naturally. I mean you don't select the gear as it's one continuously changing gear. What makes it change the ratio to stick to the same rpm regardless of bike speed?
I had this idea a while back of some kind of CVT where the gear sprocket would effectively open up as vehicle speed increases by way of centrifugal force enlarging the diameter by some kind of calibrated...spokes with pinned roller ends, that allow the thong to enlarge or contract to suit the speed.
Does that make any sense? And could it be a possibility?
a CVT Superbike is going to be unbeatable no question.
but the downside is you can't have fun being stuck in a certain rpm
it's sort of like you're stuck in 6th gear and you're just feathering the clutch until the engine can manage it.
if you ride a Scooter you probably know what im talking about
the belt itself is somewhat in multiple gears at once. the inside of the belt rubbing on the variator wall is smaller diameter than the outside of the belt. the only way to escape that is by things slipping and rubbing. its a bit like wide car tires. from one side of the car to the other you have a differential but what about from the inside edge of the tire to the outside edge eh? something has to give, and it does, with heat and wear in return. small scooters with small torque and small belts have much more efficient drives than larger due to this. And they already overdrive the belt, with reduction in the hub so the cvt itself sees more rpm and therefore less torque. similarly many bikes overdrive the clutch and transmission at higher rpms and get the torque back from the final drive so they can carry lighter gears and clutch. a benifit you touched on in the fact that 5 out of 6 gears are dead weight while the machine is in operation.
parabolic wheel cvt's aren't a heck of a lot better either in theory or practice and the all steel belts are mainly just a material advancement. some systems (Nissan juke I think) run basically a gang of a few small cvt's so they can handle bigger torque with minimal loss all at the cost of compexity.
I avoid any kind of automatic transmission,because i like shifting the gears myself.the thing with CVT's in cars is there using them for gas mileage not power delivery.i don't ride scooters or snowmobiles,but i think there are more set up for power range.with a manual i can do both.I'm sure someone is working on this problem.that is going to make it more complex expensive and bigger.I like the simple solution,drive a manual.
electric engine stering cvt position like in burgman 650 plos some engine with constant power dont even need this just wide peak power at 100% throtle open from let say 2000 to 6000 rpm and you have both .
In one of Hub Nut's U-Tube videos he changes the CVT belt on his restored Invacar project and demonstrates it in action during testing. He points out that the engine the largest capacity used with a CVT and is stretching CVT transmission to its limits.
Belt wear belts out far faster than oil filled gearboxes do gears. The more torque put through them, the shorter the service life.
Then there is the squealing that a worn CVT belt makes to contend with.....
Why snowmobiles use cvt for years?
Because for snowmobiles size isn't a massive constraint, and slip in the system isn't that much of an issue in regards to the track and all its components. A motorbike gearbox is compact and it works, with no slip.
My CVT belt isn't square. The upper section - yes, but the section that bends is curved for the ramp angle. It is out of spec with more than 1mm of wear. My belt was replaced recently and it is double ribbed. Typical belts only have ribs facing away from the casing.
And you have a snowmobile yes?
My snomobile is a 1300cc turbo triple 4stroke it makes 250hp i dont know the torque? but i would say its more about mass and space(lack of space)on a slim bike then slipage?Cost also! Good cvt’s that take all the torque you want cost alot!! And take’s up lots of space
indeed... and cvts have losses too... and you need some controll mechanism, you see for fuel economy you may not want to keep the engine running at the rpm where it produces the highest power figure, not to mention engine longitivity... sometimes you would need to keep the enigne at an rpm where its most efficient..
yep .
Well explained thanks.
Yes. Yes! Do a vid on relativity!
What we must all realize is it's horses for you know what I have a Mana great bike but don't think its an R1 or an R6 and for that matter don't think it's a Vespa
It's a bike with auto gearbox Great if you have one arm or are old like me or just like riding bikes and not scooters it's great infact more than great its a bloody good bike
great for touring or knocking about town The gearbox/auto belt works fine I will never get rid of mine no matter what other's say its good fun and most important
IT AIN'T A FUCKING SCOOTER OK !!!!!!!!!!!!! Matt as always does a great job of explaining what things are so well done Matty now you can carry on !!!!!!!!!!!!!
Cvt in scooters have came a long way watch zip stunter he has he hp 2 stroke builds I'm talking 30 horse power and he tunes them great they dont loose as much power as you think they would in scooters
Audi had the Multitronic in their diesel (and petrol) cars, mostly in the A6 if I remember correctly. On the diesels at full throttle it just ran at 4500rpm the whole time, kinda cool. Sounds shitty anyway so it was alright. But if you google gearbox failures multitronic you probably know what mechanics think about that thing. The 7-speed DSG (double clutch) just absolutely fucked the cvt transmission, luckily.
CVTs are awsome. But i still like the sound of gear shifts. Listen to the experimental CVT F1 car some time. It sounds surreal. Just a constant whine at one specific frequenzy all The way. Awsome... But wierd.
Love my scooter tho.
One Newton-Meter used to be equal to one Joule, which was the amount of work done if an apple that fell one meter onto your face while you were trying to sleep under an apple tree. It's a very small amount, but annoying nonetheless. Now we use Newton-Meters for torque because nobody really believes that Newton got hit by an apple. Some of this might be true. But I doubt it.
wut
9:30,... Matt, them gears sure look like boobies.
Can you tell more about Toroidal CVT? And why it's not used anymore?
All friction based CVT designs suffer from limited torque capacity before the drive slips, but with a V belt design the belt wedges itself harder into the pulleys as more torque is applied, which boosts torque capacity (but also ruins efficiency). The toroidal CVT doesn't have this action, so torque capacity is a problem. Nissan developed their Extroid CVT transmission ~20 years back with uses a toroidal design, and uses a special transmission fluid to transmit the torque between the rollers rather then mechanical friction but they were still unreliable, and their latest CVT now uses expanding pulleys and a steel belt as do virtually all the other automotive manufacturers CVTs.
a question the Gilera gp800 uses a cvt transmission with 73nm of torque. would it not possible then to use a cvt on a 600 sportbike (torque around 70nm)? but with cvt You always ride on your max power and not torque. maybe that's the answer?
I guess its a good thing they don't use them. imagine how boring it would be to ride a bike with a CVT!
i agree, that,s why Daf,s were such great racers!-but, yeah, iagree, so why so little interest
There are plenty of snowmobiles, atv's and utv's that are high horsepower machines using CTV. Many sleds that come from the factory with over 200 horsepower.
Are you deaf? Yes there are - but they are massive and slip like crazy.......
@@dirtygarageguy You ever ridden a sled before?
No.
@@dirtygarageguy You would be surprised on how well they hook up. Especially on a picked track in low snow or icy conditions. There are plenty of sleds that weigh less than 550 lbs making 160-170 hp and 110 ft/lbs of torque bone stock. As for UTV's, I'll give an example. A Polaris RZR 1000 turbo side-by-side weighs about 740 lbs and makes 168 hp/114 ft/lbs of torque. No where in the manual do they suggest not riding in high traction conditions. You can buy one with awd if you want. If the belts can handle those machines, I'm sure they would be fine on a bike. You are comparing scooter/low hp setups against traditional gear boxes. Check out Skidoo's PDrive cvt system. You might be surprised how much effort snowmobile/atv companies put into making CVT's handle the big hp engines of modern snowmobiles, utv's and atvs.
Belt drives are very inefficient compared to gears.
Snowmobiles use them because they have to have constant power to the track.
Shifting gears in two feet of snow at wide open throttle won't work on a snowmobile.
Why use a belt CVT on a motorcycle when it will result in significantly less horsepower getting to the rear wheel?
As for horsepower limits, the old 1000cc Thundercats from the 1990s had 172 HP stock.
Standard HP for an 800cc two stroke snowmobile these days is 160 HP.
And as others have said, lots of two stroke snowmobiles with turbochargers have over 300 HP through a belt CVT.
There's going to be a part 2 to this series. It not just about power but also size - cheers for the comment - matt
Scooter belt is not Square! They are like a cut off triangle and sits on the angled plate.
Yes I know, and that helps slightly with the friction-ish, more in the next video
Many Large Farm Tractors now have CVT Transmissions I think that Fendt was the first successful Brand they are German
Are you a teacher? If not you should be haha! great video bro!
did you learn anything?
If yes - then yes I am
if no - then no I am not
A good example is with an old snowmobile lift up the rear give it gas watch the belt just like the gearing on a motorcycle sprockets down in the rear up in the front the faster you go
if Nissan could develop a CVT for a 3.5L v6 which, in the Maxima atleast, produces 371Nm (274lb/ft) why won't it work on a sport bike? Would it be engineered too big for such an application?
Pretty much, just too big, and heavy - Part 2 is coming this weekend - matt
The Workshop thanks for the reply. I'm a new subscriber and I look forward to seeing more interesting things from your channel
There's nothing really wrong with a CVT except the absolutely INSANE price of CVT fluid...
yeah that a the cost of power bands lol
That and the drone. it gets so annoying.
that's the real reason they haven't taken off in the automotive scene. that and their rubber-band like throttle response.
I saw on TV recently here in the US there is small a small City Style car that uses a two single cone style CVT transmission but I've only seen a few commercials for it and that was two or three years ago maybe you've seen it maybe you can let us know what the deal is with it
Sorry I just started watching your Channel yesterday I keep forgetting that it's a bike Channel not a car Channel or a mechanic Channel and I do like your input on the different things that you noted but from an engineering aspect I would like to know your thoughts on these types of cars are the size limitations and whatnot of the CVT
Not a problem dude, but it'll have to have its own video - matt
What's the torque limit for a scooter CVT with roller weights/torque spring & centrifugal clutch?
As in when the drive pulley is accelerating too fast for the belt to grip
Well that would be the inertia of the rollers and the angular velocity of the rotor against the load.
So explain the Apriia Mana 850 GT which of course comes with a CVT transmission "www.webbikeworld.com/motorcycle-reviews/aprilia-mana-850-gt/"
?? Seriously ??
I'm so happy you've mentioned the Aprillia.
1 - It has gears for one, a 7 speed planetary gearbox after the CVT output. Hence why you can select gears manually.
2- the thing is massive and weighs double that of a standard 6 up gearbox
3 - 840cc and it puts out 55hp at the rear wheel? And you wanna stick that on a R1 with 190HP? Give me a break
4 - Put Aprilia mana 850 problems into google and all you'll see if gearbox/CVT problems.
5 - R1 = 99Nm torque Mana 850 = 54Nm just less than half
6 - God knows what it costs, but 32 electric motors, 2 worms drives, 19 gears in the gearbox, and electronics package
7 - the bike weighs 234 Kgs that's 35 more than the R1
8 - Aprillia pulled it from production in 2011 becasue of all the warranty claims.
Sound like a good idea?
And yes I'm being serious.
The Workshop some people type before they think a mate . keep up the good work cheers
Except you are wrong again: ---- ------ "sparts.aprilia.it/Marche/apr/Cataloghi/400700/400700_46.gif"
One final FIXED reduction gear after the CVT. You can see the output sprocket. The 7 speeds are computer assigned ratios for the drum to ease veteran rider transition.
The Honda is (and was in the 70's) an automatic shifting transmission. Aprilia is not it is a CVT.
"sparts.aprilia.it/Marche/apr/Cataloghi/400700/400700_46.gif" not talk just facts. It has no changing gears. fact
Does it suck? absolutely I would ever own one but the fact is they made one and it is a viable product. Jay Leno drove it.
Very true, and my bad. I read an article way back 10 years+ ago when Aprilia were hinting at what they were doing. It stated that from interviews at a bike show that they were working on a CVT and planetry gearbox arrangement with 7 to 8 gears. I emailed a friend today who worked at Ducati and he told me they opted out of that design because of costing. They had to back down the power and use an electronics guide rail to give the sense of 7 gears, by picking 7 ratios of the CVT.
Totally caught me out there dude. My fault on that one.
How about a hydraulic torque converter type transmission?
I wonder how the William F1 cvt worked
And the Dutch Daf puschbelt. What about that ?
What about it? I'm sure I made it clear that one of the main reasons is size and mass.
So hypothetically, could you put a CVT in a Honda CBR600RR??
Yes, it would be massive though
Wtf was that that flew past the cam @ 8:23 ?
Helicopter!
Yep! I saw that. It was an insect from the Cambrian era?
You are incorrect. CVT are meant to be run at a constant RPM at peak HP. The step you show is a compromise the auto use
because the drivers dislike the sound of a constant rpm engine.
WTF are you talking about? How the fuck is a vehicle with a CVT meant to run at constant rpm/velocity? You do know that we have brakes and speed limits?
You really are an idiot. Usually I not this hard but you have missed the point of transmissions full stop. And starting with;
"You are incorrect."
means what? Go on genius - what the fuck are you talking about? As a vehicles speed increases the ratio required is different due to the drag experienced at different speeds. Have you heard of acceleration?
This is whats said on the physics of a CVT belt drive. Maybe constant RPM is confusing. The constant RPM fluctuates within the powerband. Picture a snowmobile ((all CVT) they only engage when the revs reach the powerband. BTW your name calling only proves who the idiot is here. You don't need to stoop to such a lowbrow monologue to make a point.
how CVTs are used in cars with 1.2 L Engines?
How? They're huge, that's how...
Totally unfamiliar with CVT even though I started on and rode scooters years ago. I've moved on a very long way since then mechanically but not got an inkling on this LOL. Understood the principle though and would love to see this as some sort of CVT tear down on an actual system.
I have 2 kicking around, will have to set one up for a demo - matt
That would be very cool indeed
cars like Subaru has CVT.. don't really like them, but torque can't be the reason why not use CVT in bikes..
to be able to handle the torque of the engine, subaru's cvt is big thus heavy. you couldn't put something like that on a bike.
As petri said. CVT's can be used on pretty much everything and have. Size and weight of a system that could handle the torque is the main issue. There will be a follow up video coming soon - matt
That is to true.. you can fidle with everything in car, cos any ways there is like 5-7 bikes worth of mass.. Still when you think about it, I don't think it would be good to drive. There is no sens of feeling in that one. CVT just goes and goes and goes. Loosing sens of speed would be so easy.. I don't think I would like it more then an automatic transmission.
@@dirtygarageguy
So how do we expain these snowmobiles that are making hundreds of hp, and running close to 250 mph in 1000ft? They're not that big or heavy, and every single one uses a cvt.
@@DistinctOgre Look at bikes with snowmobile engines, they are very wide and large. Sure you can re-design it for a bike but they would still be much larger than a normal gearbox.
If only I had the stuff to build my idea of a good cvt. No belts or rollers and less parts than a gear box.
email me - matt
I guess 800cc snowmobiles with CVTs are just imaginary...
Great video. I think leyland made a car with a cvt in the 70's it did 60mph forwards and 60mph backwards. Have they every done a motorcycle or car with a hydrostatic gearbox like mini diggers & mowers have? I guess hydro are heavy over heat and don't make too much top speed. I also was told they sap about 15% of power from engine.
" I also was told they sap about 15% of power from engine."
- alot of transmissions designs so, friction, sound, heat etc All this energy has to come from somewhere
Interesting discussion about why not CVT usually occurs on motorcycles.
I think you miss some of the arguments against CVT. Owned a turbocharged snowmobile, Yamaha Nyro with 270 hp. Must say that the CVT on this machine had good reliability. The belt could handle this power very good. In theory, CVT should be a good option despite poor efficiency.
The problem with CVT on this powerful snowmobile was that the clutch had to have heavy weights in order not to overrev. This causes the CVT to gear up very quickly, which in turn gives a poor driving feel and poor response.
On motorcycles, I think most riders want to control the rpm and torque themselves, something that only a transmission can offer. That gives simply a better riding experience, expecially in corners, breaking,different riding conditions and speeds . A bit like why most racing cars do not have an automatic gearbox. Maybe CVT is a excelent choise on a dragbike?
I don't know too much of snowmobiles or engineering but my suppose is that the snowmobile track will break traction from the ground and slip easier than the CVT will overcome friction between the band, while with a road bike the cvt will break traction and slip from the band before the tyre will break traction from the ground. It's just my guess since it always seems there is some degree of tyre slip on dirt I'm guessing there is some on snow as well. Maybe since snowmobiles seem a bit wider and heavier than bikes the transmission can be reinforced more and still meet a good performing weight and so the CVT could handle it. I don't really know honestly just my thought,
I'm sure production costs and competing sale price come into the choice of selling a bike with a proven transmission that works well or a more expensive but slightly better performing one while risking losing the feel of shifting gears a lot of bike owners probably would sorely miss if they move to a CVT.
Cvt's maybe faster but it feels really boring they should be used in mopeds and prii only no motorcycles!
Visual aid czcams.com/video/R8AzqtomwD0/video.html DAF variomatic.
And who keeps disliking these videos? muppets.
snowmobile fans
Is DCT better vs CTV
cctv is way worse
Snowmobile cvt can handle loads of torque...
For their size they should do, and there's also alot of traction losses, that and the cold weather is why they are used. Try fitting a skidoo CVT in a superbike.
The only times I've experienced excessive belt slippage on a snowmobile is when the engine isn't torquey enough and it pulls a load that is to heavy for the engine. That is why work sleds often have low gear and mechanical reverse. Slippage can also be an issue if the belt or cvt is worn out. Snowmobiles usually don't get very high mileage. So the snowmobile cvt is mostly made out of aluminum.
douglas and daff
Rokon Motocross Bike they were competitive .. and got a Bronze Medal in an Italian ISD race
www.off-road.com/dirtbike/tech/vintage-dirt-bikes-a-look-at-rokon-automatics-53152.html
I'm going to call you the professor
I'm going to call you Albert
you can call me anytime you want as long as as its not to early in the morning
What about the hydraulic torque converter developed by Koenigsegg for the Regera? It is around 8 or 10kg i think and can handle 1500hp. No gearbox on that car.
What about it? Your forgetting the 3 motors and the giant battery, do they weigh 8 - 10kgs all together?
Christian himself explains that if you eliminate all electrical propulsion the car will do 0-60mph in 4 seconds. I'm sure I might be missing something but it's still an engine with a powerband. I don't see how this techonolgy couldn't be adapted to motorcycles. Their camless technology too.
"Their camless technology too." you mean Freevalve which hasn't been implemented yet.
"I'm sure I might be missing something but it's still an engine with a powerband." -
I don't understand what you mean by this?
I mean it's a relatively normal engine, capable of 0-60 in 4s with that torque converter without the help of electrical motors. I know I might not see all the details as weight and power of the car play a big role but it seems achievable in a motorcycle, not with that extreme performance but at least usable in daily riding conditions.
"I mean it's a relatively normal engine, capable of 0-60 in 4s with that torque converter without the help of electrical motors."
- Normal?!!!! -
A twin-turbocharged V8 engine with a 5.0-litre capacity. It produces 820 kW (1,115 PS; 1,100 hp) at 7,800 rpm and 1,280 N·m (944 lb·ft) at 4,100 rpm.
Would you call that normal. The car can accelerate with just a 2.73:1 reduction because the engine produces 1,280 Nm of torque @ 4,100rpm. That's 600 Nm @ 2,000 rpm. Of course it can pull away that fast.
I also found what the batteries and motors weigh -
"Koenigsegg reported that the omission of a gearbox and addition of
electric motors and battery only added 88 kg (194 lb) compared to what the Regera would have weighed with the same combustion engine but a 7-speed dual-clutch transmission (DCT) and no electric motors or batteries."
- only added 88kgs - ONLY lol
Great videos.
But you release too many, to often :)
I can't keep up.
You need to quite work lol then you'll have time
Del does not like these vids !!!
I love the Idea of cvt can you remember the Dafs and the volvos czcams.com/video/R8AzqtomwD0/video.html
I also like the new Keorneseggggchgegv (word salad swedish Supercar) although that's just a final drive and a torque converter.
F1 has toyed with the idea over the years to little success. The only usable and drivable linear torque curve is from electric sadly and nobody wants that shit.
Do you mean koenigdickhead lol
it works on a 200-300hp snowmobile.. talk about tork.. lol
do it? No slip, over-heating etc. A bath tub can float, doen't mean it's a good boat
The Workshop every snowmobile uses a "variator drive" No slipping if adjusted correctly. not even when driving in water, where traction is extremely good.
bad if it becomes too wett.
not fuel efficient at al, on anything that moves somewhat easy. thats where the real issues starts for variator drive on a bike.
the unabillity to coast at low RPM at a high speed.
say you have variator to activate at 3000 RPM. then you have to constantly keep engine above 3000 RPM to not lose momentum.
work's great on something that constantly need to have momentum.
in deep snow.
in sand.
uphill.
etc.
"The Workshop every snowmobile uses a "variator drive" No slipping if
adjusted correctly. not even when driving in water, where traction is
extremely good."
Its called a CVT Continously variable transmission. And yes it does slip when you try and stick 200-300HP down it. This why this type (belt type) is not used in cars etc.
The Workshop well.. in Sweden the system used in snowmobiles and other wehicles, is called a variator.
there is no slip in a snowmobile. if adjusted properly.
Volvo used it in a car..
The Workshop do a search on youtube.. Mountain machine turbocharged.
snowmobiles on water in Sweden.
why not just check out criss burandt. and ask him if his snowmobiles slip? 200-300hp with fullzise track's, 100 cm paddles..
Here is a good Video of a Christini two wheel drive they are like $9,000 very reasonable Yamaha built a two wheel drive WR-450 with Olin hydraulic drive and sold it for $24,000
czcams.com/video/si-bI84SZKA/video.html