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Old 05-02-2011, 11:07 PM   #16
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Personally, I subscribe to the theory that there is two types of grip roll... identifying which is happening then means you can resolve the issue a little better

The first is if the car is too stiff, in which case it's so reactive that the car then flips over the outside edges of the tyre. Usually this type happens with little warning, and is more noticeable when being aggressive with the steering, usually happening on the way into the turns, with the car rolling over the outside front tyre. In this instance, is difficult to get rid of fully, but a little softer (make the car roll more/less reactive), wider (axle shims) and a bit more expo in the steering can really help. One thing that I know does help in this case as well is less rear droop, as it stops the weight transfer forward.

The other type is the car being rolling too much, which is normally easier to spot as it will tend to happen once the cars fully loaded... which is what sounds like is what is happening here. In this case, stiffer is better, so high Rc, harder spring, stiffer roll bar, more droop should also help.

I will say these two theorys probably won't work in every situation, but gives some general rules of thumb. Figure out what is causing the traction roll, then combat it..

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Old 05-02-2011, 11:24 PM   #17
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Quote:
Originally Posted by AlGio View Post
The simple solution to traction roll is to raise your roll center (yes RAISE). This will decrease your roll and decrease your grip. You can try this on either the front or the rear or both simply by lowering your upper link inside attachment so that you have more of an angle between the upper link and the lower arm. Some of the other things that were mentioned will work also
(stiffer springs, roll bars, and glue on the sidewall to decrease flex, etc.)
but the simple fix is the roll center.
x2 Raise the inner a-arm block (raise the roll center). This will correct the traction roll issue. And this will have bigger effect than lowering the upper arm.
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Old 10-31-2011, 08:37 AM   #18
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I would like to take a live to this thread again.

Yesterday I was driving stock after long time. The car was acting well but was driving too much on front. Especially in the slowest corner which was just after the long opposite side corner. Just before apex when I was on full throttle it needed only a very little force to roll over. In many situations it looked like I have lost all grip of inner wheels and car was driving that corner on its own which mostly resulted in a drift or very sharp cornering in a moment. In some occasions it just needed a bump to roll over very quickly.

I am wondering what should I do.
Adding a sway bar to front?
Adding more front droop?
Stiffer front damping?
Changing front roll center?

Thank you?
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Old 10-31-2011, 08:56 AM   #19
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When a car is traction rolling you ultimatly what to take traction away from the car. Stiffer springs, roll bars, stiffer oils
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Old 10-31-2011, 08:57 AM   #20
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Quote:
Originally Posted by [email protected] View Post
I would like to take a live to this thread again.

Yesterday I was driving stock after long time. The car was acting well but was driving too much on front. Especially in the slowest corner which was just after the long opposite side corner. Just before apex when I was on full throttle it needed only a very little force to roll over. In many situations it looked like I have lost all grip of inner wheels and car was driving that corner on its own which mostly resulted in a drift or very sharp cornering in a moment. In some occasions it just needed a bump to roll over very quickly.

I am wondering what should I do.
Adding a sway bar to front?
Adding more front droop?
Stiffer front damping?
Changing front roll center?

Thank you?
TryHard wrote the most sense in this tread a few posts up.

Basically, you need to identify the kind of grip roll you are having, and then try and cure it, because the cures are opposite.

First kind of grip roll is what I would call "instantaneous" grip roll - at the moment you make a steering (or sometimes throttle) input, the car will just flip. This is usually caused by the car being too stiff or having insufficient droop, the weight is transferred very rapidly to the tyre edge and the car has no option but to go over.

Cure for "instantaneous" grip roll is softer settings and more droop. I see this kind of grip roll a lot in Mini racing, because with the Mini it is easy to unwittingly run a zero-droop or even pre-loaded suspension setting.

Second kind of grip roll is "late" grip roll, where the car rolls too deep into the suspension and either bottoms out or just lets the inside wheels lift too high off the ground. This is the kind of grip roll you can see coming, often you can catch it by lifting off or decreasing the steering input.

Cure for "late" grip roll is stiffer settings, and to an extent a decrease in droop (but not to zero or pre-load).

Taking grip away from the tyres (either with a harder compound or by the "magic" trick of glueing the sidewall) will always work, but you might find that you lose steering and/or overall corner speed.

Like all things in setup, it's about understanding what your car is doing, and finding the right solution to get the balance you want.

I suspect that your car is set up too soft on the front suspension, but first of all I would double check that the car is running a sensible basic setup. Sometimes when you leave a car for a while things can "mysteriously" change their settings, or you simply forget which settings you had put on it.
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Old 10-31-2011, 09:19 AM   #21
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Problem is that its upgraded T1R and racers sheets on it are lost. I have found some T2 sheets and made the car similar. The car is completely rebuilt and re set so there shouldnt be any problems of mysterious settings.

I have most probably the second grip problem.

My front droop is already close to zero.

I will buy a front sway bar I mean.

Thank you.
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Old 10-31-2011, 10:25 AM   #22
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Most grip roll can be cured with softer all round springs. Yes the car rolls more but there is less initial bite at the front and less abrupt unloading at the rear. I really would not accept this at first when someone told me to try this but when i did, i was sold.
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Old 10-31-2011, 10:40 AM   #23
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Originally Posted by YZFAndy View Post
Most grip roll can be cured with softer all round springs.
This.

Softening the springs will indeed allow the car to roll more... but it will take longer for the car to reach its total lateral load transfer.
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Old 10-31-2011, 10:45 AM   #24
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Quote:
Originally Posted by TryHard View Post
Personally, I subscribe to the theory that there is two types of grip roll... identifying which is happening then means you can resolve the issue a little better
Bingo. This is why you see two completely different suggestions for solving it. Without seeing or even driving the car, it's hard to tell which one it is.
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Old 10-31-2011, 12:43 PM   #25
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thicker oil "might' help-

frnt outer tire traction roll-(carpet) thicker frnt oil
rear outer tire traction roill-(high traction asphalt) thicker oil all round
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Old 10-31-2011, 12:47 PM   #26
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I mean I have told a description when it is happening only. Its not sudden. It happens just before apex and mostly it happens with initial little bump on front right tire at right handed turn. (By little bump I mean taking it across 3-5mm curb)

Iam using old blue Xray springs which are one level stiffer than white which were used by most racers.

My friend was having the same issue as me and he is using front sway bar.

My tires walls were not completely glued to disc so maybe that was the biggest problem.
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Last edited by [email protected]; 10-31-2011 at 01:03 PM.
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Old 10-31-2011, 01:11 PM   #27
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I had grip-roll problems this weekend. In the sweeper, the car would bicycle, or "plank" as I call it, and pick up the inside tires. From there, the excess load overwhelmed the outer tires.

I added 2.5pm of droop to each end, and lowered the arm blocks 2 settings. On my TC6 this was from 2B-3B to 0B-1B. I also lightly glued the front sidewalls.

These things instantly fixed it. I was going in the wrong direction initially based off my experience on low/med bite carpet. On really high bite, the opposite seemed to apply. If I ever ran more than 2mm of droop at my track, the back would get loose entry and mid-corner. By yesterday I had 3.5mm front/4.5mm rear. It actually kept the whole car more planted and rotating better on the high grip since it wouldn't pick up inside tires in fast turns.
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Old 10-31-2011, 01:20 PM   #28
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My tires walls were not completely glued to disc so maybe that was the biggest problem.
That's for sure
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Old 10-31-2011, 01:47 PM   #29
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Final traction roll solution list :
#1 : lower roll center.
#2 : lower center of gravity.
#3 : less steering EPA.
#4 : re-dust or CA glue tire outside walls.
#5 : check side to side and front to back weight balance.
#6 : run a lower rear ride height than the front.
#7 : run thicker oil.
#8 : run a little more droop all around.
#9 : run softer springs all around.
#10: run anti dive front and smallest pro squat rear.
#11: run your shocks as flat as possible.
#12: use tire sauce only on the inside of your tires.
#13: increase all around camber slightly.
#14: make sure your front tire bearing/shimming is good.
#15: make sure your front wheels are balanced.
#16: make sure your front cvd's are good.
#17: make sure your steering linkage is tight.
#18: make sure your body is not dragging while turning.
#19: calm down and stop turning too much!!!


If none of the above works, go FLY AIRPLANES ! They don't have traction roll issues !
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Old 10-31-2011, 03:12 PM   #30
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I would also try changing driving. Slower (more braking) and tighter line in that corner.
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