Small Geared Hub Motor Showdown, Bafang G311/G310 vs Shengyi SX1/SX2
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- čas přidán 5. 08. 2024
- In this clip we compare our two favorite small geared hub motor systems; the G311/G310 series from Bafang and the DGWX1/DGWX2 motors from Shengyi (which we've abbreviated at Grin to SX1/SX1). Both are well engineered geared hubs with helical cut gears, good serviceability, and punchy enough performance for pedal assist ebikes. But they differ in their power and torque capabilities.
If you have lots of hills or you transport things with your bike, then the smaller G31 will likely be underwhelming and we would recommend the SX motor system. We have seen many people overheat and damage their G31 motors by pushing them beyond their capabilities. For commuters who pedal a lot and just like a boost, the smaller/lighter G31's are pretty much perfect.
More detailed info is available here:
ebikes.ca/product-info/grin-k...
ebikes.ca/product-info/grin-k...
Pricing is on the store page at the end of the links above. We don't post prices in our videos since that changes over time and we want the content to stay relevant. In general the Shengyi motor is a bit less expensive in spite of also being more powerful.
Video Content:
0:00 - Intro
0:54 - Similarities (Freewheeling, helical gears, disk)
1:24 - Serviceability
2:01 - Bike Compatibility
2:24 - Combined Speed/Temp Sensor
2:35 - Size and Weight
3:02 - Internal Construction
3:47 - Noise Levels
4:12 - G31 Limitations
4:54 - Power
5:35 - Axle Design and Torque Arms
7:33 - Summary - Věda a technologie
Really appreciate the time you put into sharing your experience!
very informative, thanks for your hard work to explain everything.
Exceptional I learned a whole bunch… Thanks…
Hey what a cool channel! You go really deep into how they actually work (which is important in ebikes). I just bought a Bafang G062 48v 1000w. I heard good things about this brand. I hope it lasts!
The G062 is a nice motor for sure and we'll actually be offering a version of this hub in a couple months too which will also include the temperature sensor. So you'll see it on our motor simulator and probably in a teardown video soon enough as well.
hey @Adrian where did you find the g062 48v 1000w? Seems hard to find them at the moment, in particular the cassette / 190mm dropout variety ..
Thanks for the information. Be Well.
GrinTech really knows what they are talking about and when you get into it, you see how much attention to details is put into it.
Fantastic content. The depth is really appreciable. Love from India🇮🇳
I just bought a random electric bike at auction with what I've learnt has the Shengyi SX2 rear hub motor. It was paired also with a 52v battery (unknown aH). So far I've got it to 58kph with a 36T chainring and pedaling. Sounds like it's a good design so hopefully it lasts!
Great comparison!
Very beautiful guys! 😇🌎💫
Does anyone know what Nm the torque should be on the axle nuts? I do mine (M12 axle with 10mm flats) at 40 Nm and it's stayed fine for nearly 1,000 miles, but I wonder what Bafang themselves recommend for the torque.
Perfect road bike build!
For a serious roadie unaccustomed to the added weight, the G31* paired with a tiny battery is still a valid choice IMO. High speed powered operation favours direct drive ofc, but I wonder if some people aren't mainly using a motor to save their knees from a standstill, and "overrunning" the motor (clutch) at the top end with leg power...
@@fun_ghoul I'll let you know after my build comes out. Prefer the dropout with torque arms instead of the g310 option. Actually the g310 was my first choice.
Agreed. I (90kg) was sold on the front G311; small size(is that a dynamo?), small weight and silent operation , but ripping apart my forks is not an option - so I'm more than happy to change to front SX1 with torque arms - and enjoy the bonus extra power and robustness. Batteries will be under seat LiGo+ x 2 or x 3 up to x 6 for that long hilly trip. I also could use my trailer with the SX1 - cool. I'll come back here with finished build and use report.
Would you have any idea why would rear motor make noise when with load and speed would drop to 13km vs 39 without load? I checked inside and did not see any physical damage . Do you have any video on how to fix it?
I have an old motor with the number: SY 24 28 110 12 1
Is it a shengyi, and if yes, which model? Do they produce inrunner and outrunner? I need to know this for the motorsetup
Interesting!
hi! any experience in how other controllers handle the combined speed+temperature signal? would love to use one of these with a kt controller or similar budget options
They generally aren't programmed for it. At low temperatures it would show speed readings as normal, and once the motor thermistor got beyond a certain temperature then the voltage signal will be too low to cross the logic 1 threshold and the speed will just show 0 until the motor cools down. If you don't care about the speed reading on the display then this doesn't matter one iota. If you want speed readings at all temperatures, then you can simply open up the motor and snip the thermistor out.
Great informative video as always. Anything you can say about the motors that super73 is using on their bikes ?? Thank you
From the photos they look like the Bafang G060 fatbike hub or an equivalent clone, as there are many companies that have similar looking motors to this. Without an explicit model number it's difficult to say. The G060 is available with 3 different thicknesses of motor core for 350W, 500W, and 750W nominal models, all of which share the exact same outer shell dimensions.
@@GrinTechnologies thank you
I read reviews online that said that Bafang quality control was possibly not very good, because actual power output varied quite a bit from the spec's. Have you guys seen that, and is Shengyi reliable as far as meeting their stated spec's?
Bafang if anything is quite conservative in their specs, they can safely delivery more continuous and much more peak power than what they advertise especially at higher RPMs. But you should know that power ratings are pretty meaningless, see:
ebikes.ca/learn/power-ratings.html
@@GrinTechnologies GREAT writeup, thank you. For your controllers that monitor the motor temp and reduce power at a certain point, do you have a web page that talks about how that works? Does it work on a curve, so the hotter the motor gets the less power it gets?
Can these motors be driven in reverse? I would like to use a small geared motor as a pedal generator for a series hybrid bike.
You can't power them in reverse because they freewheel, but you can quite easily spin them backwards to force the motor to turn and use them as generators no problem. We've had a handful of customers do exactly this.
If you are interested in studying the analytics of using motors as generators and finding the optimal RPM for a given power level, I've covered that here:
endless-sphere.com/forums/viewtopic.php?f=6&t=93482&start=25#p1375674
Yeeeeeaah!!! So much torque man!!!
Interested in doing a single speed conversion on a Trek FX1. Would the Shengyi be the best for that?
If you've got some hills to climb and want a freewheeling geared motor, then yes that'd be our suggestion. The Grin All Axle motor is a great choice if you also want regenerative braking capabilities.
Thanks for a great video. I've been riding one of your SX1 kits (urban commuting and longer distance road work) with over 3K on it now and just love the motor. I originally chose the SX over the G311 for many of the reasons mentioned in the video (but also had to go on some assumptions and erred on the side of a bit more power since I'm a bigger - 100kg guy). I'm now considering a true road bike setup for longer rides (>70k) and looking strongly at an SX2. One thing you didn't mentioned in the video that I noticed using the motor simulator is that the SXs still seem to have a small efficiency advantage on the G31xs, and over longer distances this starts to become significant in battery usage, and would negate any weight advantages. This would seem to me that aside from the lower price that the g310s wouldn't offer me any advantages for longer distance biking. Does that make sense?
Hey Mark, our dyno tests indeed showed the SX motors having higher peak and loaded efficiencies and this is reflected in the motor simulator too. At some point you are correct that the extra weight in battery needed to compensate for this reduced efficiency would negate the savings in motor weight, although that point would be when you are talking like 20+kg worth of battery pack on the bike. Most people are far from that, but if you are doing like 200+ km trips with a lot of packs in parallel then you could get there.
@@GrinTechnologies Hi Justin & Co. We talked at length about a G311 build for a long range setup on a tandem but COVID put the brakes on that touring trip. My son is now riding a 24" bike so I am thinking of a touring build so he can keep up with the adults on a 60km day with panniers. Bike + Gear + Boy would be 60kg max. I modelled best I could and calculated it would need a 36v 16.Ah battery. @mark lewis what sort of range do you manage with your battery capacity and the SX1?
what kt controller can i use with the bafang g310 ? the smallest controller?
Any controller with the Z9 motor plug on it should be up to the task as long as it can support the eRPM and can handle the combined speed/temp signal on the white wire.
Wouldn't it be possible (and relatively easy) to simply file down the threads on the Bafang hub to install a torque arm?
There's no need to file down the threads to install a torque arm, it's just that the amount of torque you can transfer across the axle flats on a typical bafang motor is not all that great. At the Nm involved it puts a huge spreading force and develops a lot of play even if things started off snug.
same bike, same road, at 30kph is the Wh per km better for the shengyi having less gear reduction stages?
Same bike, same road, same modest speed, you can expect basically the same Wh/km.
There are certain load scenarios where either the SX1 motor or the G311 would have a small efficiency advantage over the other, but it's not going to be that noticeable in aggregate.
Can you get a motor with straight cut steel gears?
I'd sacrifice weight for strength
The stock gears can easily handle the torque even when "hot-rodded" however any machine shop will be able to machine some for a small fortune, and then some if you want to do it right with case-hardened steel.
What's the difference between the SX1 and SX2?
Front vs Rear
How would the Bafang G02 (older name SWX02) compare? more power handling than the G310/311....
The G020 is more powerful for sure. We have this modeled on our simulator as the Stoke_G02 as we used this motor for a while in the stokemonkey mid-drive kits. Here they are side by side with KV adjusted to match: ebikes.ca/tools/simulator.html?motor=MSTOKE_G02&cont=C20&cont_b=C20&motor_b=MG310_STD&bopen=true&kv=8.526
@@GrinTechnologies I have an SWX02 and I already burned one climbing the mountains here in summer. It really bogs down on the long ascents. What would you recommend?
Interesting be see efficiency curve of both motors...
Acording ebikes.ca/tools/simulator.html?motor=MSX_8T&cont=C20&cont_b=C20&motor_b=MG310_STD&bopen=true&wheel=20i&wheel_b=20i Shengyi is much more eficient. Strange. Always say people, that inrunners (like in bafang G310) is more efficient.
Yeah the actual dyno test results had a peak of 85% on the SX motor and just 80% on the Bafang G310 when running at typical ebike rpms, so the simulator model is reasonably accurate here. I've never heard it suggested that inrunners are more efficient than outrunners.
I’m trying to make a beach cart using balloon tires from Wheelez and wheel chairs with balloon tires for handicap people. This is all for charity. Any suggestions
Definitely not a small motor like this. Moving on sandy beaches requires very high torque levels, probably a geared fatbike motor like the G062 laced in a fatbike rim would be our suggestion.
@@GrinTechnologies thanks I will look into it
I don't know why motor goes from 14km/h to zero suddenly is it a hall problem
Very Unlikely
Warranty? You described your products inaccurately and refused to make it right.
High wattage through those you're going turn the gears in the peanut butter
It is not wattage that damages gears, but torque, especially if the maximum torque is not derating the motor core heats up. With proper phase current limits and thermal rollback settings, there is no problem running at the power levels we discuss on this video.
will USA/canada start making electric motors like we make cars? or we just have to let Chinese engineers design them for us? and wait til they come with new models/features hoping they would work be reliable and not burn up/fail?
czcams.com/video/J32B243Apyo/video.html
You sure do pack a lot of stupid in one small comment, "em". Chinese engineers and other workers are the driving force behind the ebike revolution. Mind your mouth, a-hole.
I really want to purchase a G311 motor from Grin however all you have are black hub motors. I live in Houston, Texas. The temperature has been over 100 degrees all week (and this is NOT the hottest part of the year yet). You people live in the frozen north and have no idea what the real world is like when you do not have snow and ice six months out of the year 😞
We don't follow the correlation. In use the motor gets much hotter internally than Houston in the summer, and so having a black finish will still radiate more heat away than if it was silver.
Aren't Shengiy the junk motors that Super73 uses, no torque and usually blow up within the first hundred miles, the Bafang is the much better choice.
Your comment is ignorant, but it's not too late to delete it.
@@fun_ghoul I guess you own a super 73, it's not too late to find a sucker and sell it. 😁👍
@@mjsmjs7905 Sounds like you're the sucker, trolling for Bafang for free. Have a nice life.
Can't comment on Super73 but both Shengyi and Bafang make a huge range of hub motors in different sizes and power levels. This vid is specifically comparing the Shengyi DGWX motors with the Bafang G310/311's, and our firsthand experience with these models in particular is a much higher failure rate on the Bafang, mostly from excessive power usage but also some random instances of clutch failures even when used well within recommended limits.
@@fun_ghoul I wouldn't say that, they just had bad luck with super 73 and I feel bad for anybody that dropped 3 grand plus and had to go through that Fiasco. So who's the troll B 🤔
Do you have a contact for shengyi parts? i have tried their website email contact, alibaba page etc, trying to find parts or replacement shengyi mid drive and getting zero response.
You should contact the reseller/vendor who you bought it from. They are the entity responsible for offer retail level support. Not the manufacturer.