I always used a sway bar to get rid of excess grip but my background is on road and the only time I had that much grip was an astro turf track.The only thing that worked was changing my driving technique,instead of trying to drift or push the pace I just had to be careful on steering inputs,slow in fast out.

I'm driving an SC10 on an indoor clay track with a layout that is relatively smooth. Let's also just assume that the sweeper is out of the equation and I'll just have to drive it through the sweeper and tune for the rest of the track. The truck feels a bit over eager to rotate through all the 180's on the track and the back end wants to step out after clearing a double into a 90 straight onto another double and I think that's where the time can be made up. For the majority of this track I would rather be having to just fight a little bit of a push and be able to make more consistent laps.

Hi Fred

I've learnt a lot from this thread. Applying what I've learnt has helped my 14 year old son get from E finals to 3rd in A final last weekend. A big thank you.

However I don't understand that high roll stiffness = traction rolling. Can you explain please?

Thanks

Mike

I think its called jacking force. In other words ,something has to give .. if the suspention can't absorb the force cause of being too stiff and can't absorb the weight shift. To thick of oil can cause this as easily as to firm of a set up .
On on road carpet this is a constant battle . The fast guys at our track (Eric Anderson for one ) have their cars setup on the edge of this and they just stay in power and keep it smooth thru those areas that r the worst . I drove his car one day and I think I flipped it 5 times in one lap but with him driving never once. He considers my car a Sunday drive (and .2 slower) com paired to his but that extra .2 he has is set up and driving style ... my $.02
BTW only difference in our car setups is he has more aggressive camber links ...

So with a sway bar and the heaviest spring, I stand by my original recommendation of the softer front spring or go softer all around. Its very hard in offroad to theorize some things because you could be "rut" rolling more than traction rolling, hitting an uneven part of the ground that is causing the tires to grab hard, it happens to us in onroad too, you can hit a bump or a seam in the carpet and it will grab, even if the setup is actually on point.

Might try going softer all around if it does it with different tires . A local told me to make a tire change

I'm just going to throw this out there as a theory, let me know what the rest of you think. Seems like the true traction roll happens as a result of jacking forces like Mike mentioned and these seem to be pretty dog gone violent transitions from turning to rolling like a barrel across the track. Rut rolling, pipe clipping, or getting too low on the apron of a sweeper seems like it could happen with just about any amount of roll stiffness. These never seem as violent. Does this make sense?

I agree on the tire changing. As everyone knows, tires are everything in racing. I'm thinking that before I try anything too drastic with chassis setup, I should try just about every different tire combination I have in my tire box.

It depends if the car/truck is good on the rest of the track, I was once (or twice, or 3x) told don't tune for a single turn of a track, if its the only one giving you problems, adjust your driving.

+1 You've gotta look at the amount of time you lose in each section to figure out what to tune for. On our track I'm going to plan on my (not so) stellar driving to get me through the sweeper and tune for the nasty double/90 degree/double combo on the left side of the track. My fast lap times are about as quick as anyone in the class but I throw in some serious clunkers because of major bobbles in that section of the track.

ding ding ding WINNER !
Heres a question, why do some cars at the inner rear have a vertical ball stud in a bulkhead with multiple positions and the height is adjusted with spacers... while other cars use a horizontal mount like a tab on the shock tower that only has say 3 postions up and down with no simple fore/aft adjustment ?
Why would one car "need" one style yet another car "need" the other ?
The information in this thread is very helpful but sometimes I find one car or the other I can't do the adjustment I'd like.

A vertical ball stud allows for more fine tuning. A horizontal ball stud can only be adjusted at the level of each hole. With a vertical ball stud and washers, you can adjust to any level in between these locations as well.

If the vehicle is lifting an inside tire in a turn, I believe it was mentioned that it was a short course, this is a sign that the end that is lifting the tire is either too stiff or the opposite end too soft. Now it may be the case that adjusting this out results in slower lap times depending on the track. If this only happens in one particular corner then I wouldn't worry all that much about it. A good track is a challenge to every extreme. However if this happens everywhere I'd work on getting rid of it.

There are some other things to think about in regards to tuning that I never really touched on here. First, balance is not about weight balance but rather about spring rate balance. This means that the old myth about lighter front end cars jumping nose up or heavy nose end cars jumping nose down are really unfounded and the result of a misinterpretation of the effect of tuning. Another myth is that shifting weight forward gives more steering. This too is incorrect in a perfect world. Shifting weight forwards but changing nothing else also increases rear end roll stiffness and decreases front end stiffness which is really the source of greater cornering ability.

Saying this, if you have a great setup in handling but you are either getting too much steering or not enough, shift your weight around. Don't arbitrarily add unless you absolutely have to and please don't add solely because some pro driver did on some random setup sheet they posted. Another thing to think about is weight location left to right. Many modern tracks are very fast with very large jumps and are relatively smooth in regards to bumps. This explains modern car design. Longer wheelbases and narrower chassis that keep the center of gravity as close to...well center, as possible. A rougher track with fewer huge jumps may be another matter altogether though. If a track is very bumpy, having the weight centered over a larger area side to side (a wider chassis) will handle the bumps better since each bump will have less leverage over the weight. However a setup like this, think stick pack running side to side, isn't going to be as stable jumping longer distances or in tighter corners so there is a tradeoff for everything.

That bit should keep some of you guys busy for a while!

I have been reading and have a question? What setup changes do you make to a 190 mm TC that is traction rolling at high speed. I think the car just has to much grip only have run it two nights so far. I let two local fast guys run it and both of them rolled the car. Are tires the first thing for me to look at?

DUH lol , In all seriousness why would a designer choose one over the other ? Simply because that is the way they have been doing it ? On-road needs one style, off-road another ? 2wd needs one - 4wd the other ? No clear pattern looking at my fleet.
It seems to me the bulkhead style is more adaptable yet many cars come with the tower style. Perhaps a tuning thread is not the proper place for a discussion about this quirk but I am curious.
yes Fred I am obtuse, my teachers love me

your statement about weight shift affecting roll is along those lines, nice
It's easy to "feel" in real life, the forward shift and the timing of your turn in...

I agree with this completely, if there is a section that can net .5 a sec a lap, you do need to tune for that, there is not .5 a second in tapping the brakes to slow down a little before the sweeper if you keep rolling it, but there is 2-3 sec to lose

The tower, horizontal mount is more durable, and in general offroad cars seems to favor much larger increments in their settings vs onroad, not that I agree with it, but seems there is a lot of "this is the way its always been done".