Roll Center - The Jacking Effect & How it Affects Your Race Car
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- čas přidán 9. 09. 2021
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Many years racing real cars, constantly trying to understand how and why suspension works, or doesn't. Reading from the best usually raises more questions than answers hahaha and you show me more on a RC car than all of them put together. For the first time, you explain clearly exactly what does happen. Thank you so much for the best suspension information I've ever found.
Just sub'd and now looking into purchasing the course! I think this could not only be helpful for RC racing, but all motorsports. It has surprised me, whether it was desert racing in Baja, drag racing, or DH mtn bike racing, how little people were interested in how setup works vs just buying new expensive products. The visual aspect of your teaching is just absolutely incredible and a game changer. You just can't get that visual demonstration from words on paper or a static picture.
Another great video Joseph. Sharing your knowledge with others very often leads you to understand it better too. Sharing this hobby with my high school students often refreshes my understanding and techniques making me better as well. This is the type of thing all the "Pros" should have been doing all along.
Moin JQ! Absolute amazing stuff, which helps so much more to understand the technique behind! Thank you and keep on doing this!
This is what R/C needs. Very informative even from JQ. Love Ya Buddy
Great video JQ, very clear explanation of how everything works. I think i'll be investing into your course and i've been racing RC for 8 years and only just begun to feel more confident in my setup change choices, but your video clears a lot more things up for me.
Very informative video. I learned a lot here. I can see the value of your courses. Good work
Thank you JQ. Excellent thorough explanations.
Amazing !!! Can’t wait to test by my own!! Great work👌
This is great. I love the extreme detail. For a nerd like me that just got into rc, this is heaven
Then you need to check out courses.invisiblespeed.net
Thanks man, the depth and detail is great. I don't race but still really useful for any rc even if you are bashing just to understand geometry etc. Kiitos.
Thanks for making this video! This is the best explanation I've seen, it's very very helpful.
Brilliant! Love your videos mate. Always so informative with off road tuning but can be applied to on road also. Thank you.
great video really makes you understand the car and what actually is going on thanks
Wow, graet vid man, you really giving us (especially me) some insight on how that link works, two thumbs up
Excellent stuff. I definitely learned a couple things. 👍
yep ...... truly informing videos ! i'm only in it for fun but the level of detail is amazing and very apprecited...... thanks
Very good, thank you for sharing!
nice vid JQ !
We talking bout practice, mayne! Fantastic reference!
Excellent really enjoy learning and watching this content
Great video my man. Informative and i know understand whats happening on my car
Love your Videos!
Great video… Thank you 🏁👌
Hi.just want ti say that you have now made it possible for us all to really perform to real pro levels.thanks for the vid.god bless
Awesome job 🤩🤩
Great Video!
Great video, top level 👏👌
Thank you JQ clear explenation 🥰
Thanks à lot Joseph 🤩🤩🤩
Your vidéos are always very instructives.
a French Fan
Merci beaucoup
great video !
Great video.
Awesome … thank you for your time and great work explaining what I always preferred but didn’t know what the fundamentals were ! 👍🏽
You are right JQ, if only there was such material back then it would be a different experience with buggy. Thanks JQ.
Well you have me hooked and I will be back for the course, I am a fully qualified mechanic and I find this incredible fascinating.
You also come across as a very professional engineer and to me that means a lot if I am going to be learning from you..
You can check course content and some free lessons on courses.invisiblespeed.net
Dude, I have a buggy that likes to raise the ass end on throttle, i couldnt find anything that could explain why it was happening in a way my brain could relate. Thank you
There are many reasons it can to this in a straight line, RC alone is not one of them.
Thank you JQ for providing your insight. the only crappy thing about your video was the end. when it ended.
Nice and great video as always !
If I can, I really want to let my son to understand this. But It will need my hard work to translate to his native language ;-). Will try.
Super thanks for your hard work !
Good stuff
Nice video
Great information
can i tap that
Hi JQ.. as always great video and great explanation. Regarding your course, I have a suggestion. You have the full course and the short version for people who are starting. I think you should have a short version for the guys who are already into it and interested in the technical stuff more than the beginnings.
The short basic course includes setup and driving technique also
This animation cross section is incredible
tested today to get my car to be "in track" on my brand new xray xb2c and lowered the rear roll center as much as i dared and on that like 3 degrees of camber in the back to gain max tire contact at some point during roll.
result is that i got loads of grip on the back on carpet and almost no traction roll, can feel the car "sucked to the carpet" as the car is in corner and on throttle.
front grip on the other hand is now something i need to work on as the car is understeering a fair bit ;)
but the next time i get out to track i might test the same in front and lower roll center to se if i gain traction in front.
BTW some guys pointed out that i need to raise my roll center and doing all wrong and ruin the handling despite i feelt the car doing as i expected to gain traction as it rolled in the corners and after jumps landing whacky as shown in this video.
The best.
The two examples at 11:04, did you make RC changes via camber link or lower arm?
Hello great video had a question but in a different form of rc. I have a b6.2 that I drag race 132'. I would like to know what your input would be on the setup to get as much forward bite as possible and stay straight for the pass. Thanks
You probably want to reduce squatting as much as possible, and eliminate camber change. You should look at what full size dragsters do
Other than making sure your car isant dog tracking by adjusting the links to perfection. The next biggest step would be to eliminate squatting like he said. ^^. If you like the look of squatting on acceleration ( physics likes it as well ). Counter the camber from squatting by presetting the camber less and less negative till you find a good spot that your rc likes.
Thank u sir
That could be applied to onroad race too? Please let us know
Hello JQ,
Great video - when do you post the next video for Camber Change that you referred to at the end of the video?
J
I wont. You have to get the course to watch it. This was a preview of one of the videos in the course! 👍🏽
awesome video jq, question though was watching adam drakes recent video "MBX8 Nitro Buggy at Cabinet Mountain Raceway" and at 2:27 would that be an example of the rear roll center being to high?
He likes to run those MIP pistons with fast rebound, which I dont agree with
@@invisiblespeedrc are you going to talk about mip pistons in your new course?
Very informative, I fell out of the hobby due to lack of information/support as a newbie. This course will definitely help me get back into it, I look forward to the release. Just one question on roll centre, do ride height and sway bars also play a part in it?
RC moves with rideheight. A lower rh lowers the rc also. Roll bars dont affect rc, theyvare another way of limiting roll. If you for example lower your rc a lot front and back, the car will be very soft in roll, so you might go to a thicker rollbar front and rear to stiffen it back up.
@@invisiblespeedrc thank you for your reply. With any changes to the car where one thing can affect the same as another is there a specific order as to which one you change first. For example ride height or camber link position?
Adam Barnes yes, we talk about it in the course.
Question. If I put more caster on my Mugen truggy will it help pull the truck through the turn mid corner? I have a lot more caster on my buggy than my Truggy and it seems to pull through mid corner instead of pushing and understeering
It depends but maybe if you like to drive on power. A better change would be shorter plate on steering knuckle, link forward on ackermann plate, leaning front shock over one hole, thinner front roll bar, less rear toe in, or rear shock one hole down on tower.
@@invisiblespeedrc driving on power is what I do. I’ll try out some of these and see where it goes. Thank you
I asked this question during the Race Stars live (greetings from Poland!) but Ovca didn't ask you about it, so I'll repeat it here. Mayako will only be a nitro 8 scale model or will there be an e-version?
All 1:8th offroad cars
I will invest in this¨
Please offer the course modules for purchase individually.
Thank you for the information, I'm just a beginner running short course traxxas slash ultimate, my local track only competes on asphalt, would your class help I know there is always something to learn but just asking because I'm in a different boat concerning the vehicle.
There is a lot that you can learn from it!
Take my money 💸
Thank you so much. Where is the second part of the video?
Courses.invisiblespeed.net
Great content only concern is the audio hum in your studio portions is it that way thru the entire course ?
Life sucks and then you die. 😭
This response right here actually has motivated me to join the course as well as switch from Tekno to Mayako. No joke.
Roll center is IMO one of the biggest overlooked adjustments in RC
Did you do the video on camber change mentioned at the end? I don't see it on your channel
courses.invisiblespeed.net yes in the online course
I bought the first JQ buggie that came out, must admit it was the worst build I ever have done in my 30+ yr's in the hobby! Mostly because of bad fitting parts, missing parts, etc.
But once I had it finished, we had races the next day, so I had very little time to practice and made zero adjustments other than static adjustments i.e. toe and camber adjustments. When my race came up, I expect to get dusted, but the opposite was the case. I won all 3 qualifier's and the main, and rarely drove nitro, you guy's instantly had a bunch of orders for "The Car" the next day! I've been waiting over 10 yr's for my check for advertising your first awesome buggy!
I'm a patient Man, but how much more time do you need? 😅😂🤣
Fantastic information...can i apply some of these to my crappy china bashing rc?
Also you didn't mention how exactly you change your roll center...is it just a simple adjustment to the spring pre-load to lower the car until the inner hinge pin is lower than the outer?
While rideheight does change rc, thats not the way to do it. You want to keep same rideheigh and change rc. All that info is in the course.
is there a camber change video?
What's up JQ. I just ordered the 3 year online course. When will I have access to it?
You already do!
@@invisiblespeedrc Thank you JQ
Great video! But isn't the difference between roll centers due to the distance from the C.G. , the greater de lenght the more the car will roll?
What do you mean by difference?
@@invisiblespeedrc the effect caused by changing the roll center. For instance, by moving the roll center down (by changing the link position) further away from the CG the car will roll more, as the distance is greater, more moment. (There is also a funny affect if you move the roll center above the CG.)
The video explains roll center in a more praticale way...but it never defines the roll center and what it actually is, the axis in wich the car roll, and what is the physical effect of moving this axis is.
Anyway, maybe for a fellow engineer is to simple, haha. Overall it's awesome what you are doing.
Book tip: race car vehicle dynamics by Milliken, great book!
waiting for the camber change video over here :D
You need to buy the course for that
In touring, Is chassis flex can perform more or less like anti roll bar?
It's not the same thing, but a softer chassis will slow down load transfer because the forces will twist the chassis. The car will be less critical when it comes to setup, small changes won't affect it as much. But no, it's not the same as a roll bar, just that it also affects grip and speed of load transfer.
So THE JF depends also by the suspension upper links because if this Is inclined to Gain camber during cornering the JF IS less right?
More with more angled link
@@invisiblespeedrc yessss i now understood why... Because there Is more force that make the chassis to go up..... Another question the LENGHT of the upper wishbone has somethimg to do with the JF? FOR EXAMPLE MOUNTINY AN ARM LONGER OR SHORTER ON THE TOP CAN CHANGE THE JF ... ARM AT THE SAME INCLINATI ON BUT DIFFERENT LENGHT I MEAN ... NOT SPEAKING ABOUT CAMBER GAIN ONLY ABOUT JF
@@Drum_x_Life longer link travels less for same roll angle, so allows for more roll, this means the jacking happens later, slower
Can you please explain for the rear - Long parallel links have good geometry in bump and rebound but bad geometry in roll. Why don't you use short top link on an angle for better roll geometry ? Is the reason for roll centre, roll moment, weight transfer, contact patch etc., I want to learn?? Please also explain how more wheel positive offset, you mention Mugen, steers the rear ? And what other changes to the handling does more or less wheel offset cause ? What's the significance of the outer pivot centreline to the ground in relation to the centre of the contact patch ? I'm building my own design real race car and am excited that you have the best understanding and explanations of suspension ever !
1. Join my online course
2. Pre order my new book
💚
KYOSHO vs MUGEN! HOW Are They Different?
czcams.com/video/OYWvWS6V0Es/video.html
Is this video applicable for Crawlers with straight axles???
No
how does jacking affect the turning radius of car?
Can u upload video g4jr from team magic convert electric rc ..hope u can help me
I'm learning this for my actual car lol
Shit, now I have to buy this program so I can learn how to setup my MBX8TR eco. I wonder if there’s anything specific about truggies n the course? Probably not
Looking for the next video, sure would be nice if you placed a link in the des.
courses.invisiblespeed.net
Link is there
@JQRacingTV I was looking for a CZcams video link thanks
Is the course mainly for on road stuff?? Would any of it apply to 1/8 buggy off road?
Did you watch the video?
@@invisiblespeedrc yeah but when I went to the course most of the title stay on road
@@MeGuess_Adventures no they dont
@@invisiblespeedrc Yes they do. I just check again lol.
@@MeGuess_Adventures ok. I guess it’s an onroad course then
Hay bro I just found u you got points on drag 8th scale
is there a way I can only get module 10 its what I can apply to what I need
Same price regardless
Great Job JQ! Need any machining of aluminum parts - Contact me.
What happened wt mayako? You do not share same path anymore?
Nothing happened. This year its only for members.
Wheres the next video?
Here: courses.invisiblespeed.net/
🙋♂️
You should only pour your heart and soul into your family. Only enjoy your hobbies.
I dont have a family
Your magic jacking force is being displayed poorly. If your links were set to different lengths this would not happen. I don't just mean adjust the top link and mess up the camber but the actual working length on the correctly set hubs.
It’s not magic, it’s physics, and jacking happens with both long and short links.
@@invisiblespeedrc Oh I know it's not magic and it does happen. My point was that it can be prevented by altering the length and pivot points of the links relative to each other.
@@captainchaos3053 watch the video before commenting
How to adjust roll center!!! Lol. You said all this in depth stuff but didn’t mention how to adjust the roll center.
This is one video from my online course. Get the course if you want to know more
Also you might want to read the title of the video
he looks like nolan from donut media
you never told us ab camber change😥
You have to get the invisible speed course
I am not here to bash, but quickly explain what I have learned reading many racing books (driving, setup and suspension design) and over 2+ decades of racing.
8:54 during this part, there are many forces happening, you are ONLY talking about lateral force, your neglecting roll force (through roll couple) and a few other forces that drastically efect traction on that tire.
15:00 I totally disagree, a "below the ground RC" has a huge roll couple, and transferring more weight to the outside tire = less grip on that tire.
I think the largest error in this video is not talking about roll couple (the length of the couple) and how it affects where the roll center is,,, AND the CG of that part of the car (this is huge).
I suggest reading more books on suspension tuning and or design. I started reading these books back in the late 80s, and now they are 20 to 30 years old.
My favorite book of all time, it teaches high speed thought, "the soft science of motorcycle road racing" they are ~$5 on ebay now. Yes it it taylored to motorcycle racing where you need to focus on 5 things at once (much harder than a car), you can use the same technique to drive relatively simple 2ch rc cars, it makes you quicker and more consistent.
Thanks for sharing!
You are missing one important thing, time. The relevant point in racing is not the maximum amount of load transfer that’s theoretically possible, it’s the time it takes for load to transfer. Each section of the track has a finite time, and the relevant point is how much load transfers during that time, and also what is the position and attitude of the car as it rolls. The video is accurate for the topic and the relevant points to our cars.
@@invisiblespeedrc
Speaking of time, you had many hours/days/edits on your video, and I quickly explained what I think is wrong from reading and experience and I am not into spending to much time explaining everything. I know quite a bit about shocks and even made a shock dyno that helped my sponsor make better shocks, and yes, shocks is all about time.
"is not the maximum amount of load transfer that’s theoretically possible"
where did you get that from, not me, zero load transfer would be ideal (unless your in drag racing), but thats not going to happen.
there is a lot to this topic, I "quickly" explained roll center is one peice of this puzzle, the other is the CG on that end of the car and that creates roll couple distance, the thing you never mention, this is huge IMO, talking about one without the other does not make sense and is not accurate, they go together. And very rarely have I seen real race cars with the RC below the ground on the rear of the car, in the rear there is typically more weight higher up compared to the front, this higher rear CG makes a longer roll couple, thus transferring more weight and more weight added in a corner = less traction on that end. So making the RC below ground = less grip on that end of the car in most cases.
Also you never really mention all the things that happen when you move the rc, there is at least 8 items that moving it affects, so moving it changes many things its complicated.
In simple 2 link suspension like rc cars generally have, all 4 pivot points have a vast impact on how the various action happen, there are a few ways to lower the RC and changing different points will change other things like camber gain/etc.
With a long roll couple as you suggest (below ground RC in the rear), this multiplies the roll torque on that end, this is opposite of "lifting" the rear on the outside of the turn (on left turn, chassis is rolling right more (effectively lowering the right side of the chassis) with all else the same.
You make it sound like lowering the rear RC is the hidden speed secret most dont know about, I really dont see it this way from my 2 decades of racing (210+ A main wins).
When explaining something the point is to explain as clearly as possible each individual point separately, not every point together and how they work together. For example when explaining RC, camber gain can be mentioned, but not explained in it’s entirity, that’s a different topic. Yes the CG affects roll, but the CG is fixed now, we are discussing adjusting the RC, so discussing CG position in detail is not relevant. And finally, lowering the RC does increase the moment arm length, which is explained, but would be misleading to say that this increases load transfer, because it’s not true for us. When you enter a corner with a high RC the geometrical stiffness of the suspension (jacking) will cause more load to transfer initially. When you enter a corner with a low RC the low geometric resistance will allow the car to roll more, and transfer less load initially. This is very relevant for us, and explains how the car enters a corner, and how it will behave mid corner. What you are talking about is noise thst doesn’t change this fundamental concept.
@@invisiblespeedrc By changing rc, you are changing many things, as a minimum talking "briefly" about each of them is important. As there are pros and con of everything. There is so many different suspension designs being used that "lowering the RC" will not help all cars, why, because it changes so many other factors. And this is not talking about the huge amount of other factors (car/tires/liner/class/track type/track design/track surface/driver talent/etc).
"This is very relevant for us, and explains how the car enters a corner, and how it will behave mid corner. "
I disagree mostly with this statement, there are so many factors that dictates how the car enters the corner (including my other factors above).
In racing, there is optimum settings (hard to find) and everything has cons that you try and minimize. Another example is a tight hairpin corner and a fast sweeper, no setting (including one RC height) that is optimum for both (racing oval has proven that).
There is a front RC and rear RC, they work together based on the location of the CG on that end of the car (creating roll couple lengths) and the amount of weight transfers.
Lengthening the rear roll couple (if nothing else changes, which we know is not possible), will loosen the car. Yes many other changes can tighten it back up.
Typically the roll center is designed on the amount of roll torque on that end of the car is wanted (verse the other end of the car).
Lowering RC below ground (or just too low) can have adverse affect's (slower corner speed) on different car suspension designs.
"if this magic" was the truth, you would see a lot of cars already have lower than ground RC in the rear, as the dominate car would be looked at by all the other MFG. (Tamiya was in this boat, their crap sucked until they copied the fast MFG's and their RC was above ground and it was too low, causing low rear grip on their F1 car)
@@invisiblespeedrc Here I am passing Masami at his track (Yatabe arena) and the Japanese crowd went wild as we battled for 5 minutes. I rented a room to Hara and Berry. www.flickr.com/photos/123906448@N08/50639419023/in/album-72157717021792052/
What happened to the intro? Everyone, you will getting more understanding from the invisible speed book!
The book and the course is an unmatched combo
@@invisiblespeedrc Well dag, might as well get them both. The best of both worlds!
dynasty4851 it’s like school, you don’t jist go to lessons, you also have a workbook.
Could not follow the video
I'm not convinced by your theory about the jacking force lifting the chassis up when the coin has fallen over. If you think where the roll centre would be when you twist the hubs at 4:07, it would be well below ground level, so the jacking force would actually be downwards, not upwards. So it really can't be the thing that lifts the chassis.
You actually highlighted the same problem with your theory yourself at 9:52.
What then? Magic?
@@invisiblespeedrc probably your fingers!
It would be interesting to see static pictures of the cars shown cornering at 11:32, so it would be possible to see how much jacking had taken place compared to the static height.
@@pjay3028 you are looking at static pictures there. Is your brain broken?
@@pjay3028 you can see my fingers in the video. They are twisting the hubs, as they would twist in a corner
13:57 the only thing that saved that car was the fact that whoever was driving it counter steered in the opposite direction and when the came back down (because the whole thing did actually leave the ground) the outside front tire was pointed away from the turn. THATS what brought the car back down/level NOT the jacking effect or roll center. THAT the exact moment the car switched from flipping over to leveling out. same exact thing in the very next example. how the fuck is that your example of the jacking effect when the rear wasnt anywhere near the ground????
Because if the car would have been set with a high enough RC, first of all it would have flipped so quickly and violently that there would have been no time to save it, and secondly even with time for a counter steer it may still not recover and flip over
Also the front also has jacking
Me to y u take so long to put it out
the price is too high
If you mean the course, no it isn’t. It contains 20 years worth of knowledge, and the ability to interact and learn more for 1 year. You have no idea how much time and effort has gone into it. You spend the same amount in one weekend at a race. It’s not too expensive. It’s too cheap.
@@invisiblespeedrc I would love to take your couse. Bu for me, the price is too high. And no, I dont spend 200 on a single race
Why would I buy your course when I can spend £40,000 and 3 years of my life doing an engineering degree to get a job as a waiter at a coffee shop?
Because I got a masters degree that would take double that probably, and you would have to race RC cars for a decade while you work in the coffee shop to get to the same level of understanding 🤪. With the course you spend $400 and by christmas you have all the tools you need.
@@invisiblespeedrc sounds like a good deal then.
the narrator enthusiasm and the music don't match at all