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Old 01-12-2010, 10:18 AM   #61
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Originally Posted by captain stacker View Post
more droop, so say from 2mm to 3mm for example?

most setups call for internal limiters to reduce droop, which helps reduce traction roll.

this is a paragraph of the setup tips I look at times when im confused:
Adding more internal travel limiters is a very effective way of reducing traction rolls, if not the most effective way.
that was before every car had droop screws, no need for internal limiters now.
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Old 01-12-2010, 10:19 AM   #62
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I usually always start with widening the track width on the front (if possible)

Then I look at swaybars, ride height, roll centers etc.

Xray has a neat chart that helps with "Order of importance" and "What do I change first"

Check it out:

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Old 01-12-2010, 10:44 AM   #63
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I think that refers to limiters inside the shocks which limit indeed the shock travel. That does not necessarily limit droop.

Droop is limited however by the droop screw.

Remember droop is actually downtravel of the suspesnion arm, not up travel.

The internal limiters the text above is referring to might actually be compression limiters (in which case I would call them "external" but heck, I don't know where you found that).

More droop allows the unloaded wheel to keep in touch with the ground longer, i.e. the car will roll more before it breaks loose. Sure, that's not necessarily a cure, but admittedly you would have fixed everything else.

Not knowing anything else about any particular instance, it is very difficult to give advice. For instance a stiff chassis will need to have a softer suspension than a flexible one otherwise you might find it breaks away suddenly when the car is pushed close to the limit (if nothing can give, something has to give).

I would start by making sure I have as low a center of gravity as possible then move on to tires etc. If my car was otherwise set up perfectly but I experienced grip roll, I would only look at changing the camber (I usually start setting up my cars with 1 degree, so I would increase it slightly).

You also need to work out if the car tends to grip roll on power, off power, under brakes or all the time. Changes to setup will need to take that into account.

Gluing tire sidewall minimises tire roll and reduces at the same time lateral grip, but I do not agree it is a good tuning practice. Besides, I never see taking away grip as a good tuning measure. If you want to go fast, that means you should try to make the most of ALL the grip you can have, not give some away. Then again, I race in such difficult conditions gripwise, we're always struggling. A hard school, but a good one. Besides, at our track it is not allowed (nor are any traction compounds), so we need to work around that.
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Old 01-12-2010, 02:49 PM   #64
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Quote:
Originally Posted by niznai View Post
I think that refers to limiters inside the shocks which limit indeed the shock travel. That does not necessarily limit droop.

Droop is limited however by the droop screw.

Remember droop is actually downtravel of the suspesnion arm, not up travel.

The internal limiters the text above is referring to might actually be compression limiters (in which case I would call them "external" but heck, I don't know where you found that).

More droop allows the unloaded wheel to keep in touch with the ground longer, i.e. the car will roll more before it breaks loose.
If you are not using droop screws, limiters indeed will change your droop. Think about it. If the screw limits the down travel of the suspension arm, a limiter inside the shock will also limit the amount the suspension will travel down. In this case more droop will = less internal limiters. This is how I have to do it on my TC. I went to more droop for the reason you mention above. So the tires will be on the track longer while the chassis rolls. For my particular case, more droop travel helped.
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Old 01-12-2010, 04:58 PM   #65
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Originally Posted by MikeXray View Post
that was before every car had droop screws, no need for internal limiters now.
+1

Some older cars, and things like 1/10 trucks and 1/10 4wd drives do not have droop screws though. Most anything enginnered lately incorporates droop screws though. It can be done through the shocks, it is just a royal pain!!
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Old 01-12-2010, 06:31 PM   #66
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Originally Posted by vitomon View Post
so far from what i understand you guys recommend the following meassures against traction roll (no particular order):

-softer oil (eg 450 MuchMore)
In my experience on super high grip carpet surfaces, using more dampening (than your springs would usually need) slows down the weight transfer from turn-in to MAX tire loading. It's the MAX loading that was causing my traction rolling issues (not a loose rear dumping over), so I added dampening to the front and it slowed the entire weight transfer down curing the traction roll. I had tried reducing the dampening, but the car traction rolled more easily.

On the topic of camber, I had gone to 0.5' up front in an effort to reduce front grip and thus the traction roll. However, I had done so many little things to avoid traction rolling that when all was said and done, the car wouldn't go any faster than a 10.9 sec lap. I knew the car needed the standard changes to bring front grip back, but couldn't do any of them because of the traction rolling issues. In a last ditch effort, I glued the sidewalls AND began undoing all the changes I had made to cure the traction rolling. Whalla! The car is now capable of going 3/10ths faster per lap! The only downside to the glued sidewalls is that they actually build grip over the course of the day and need to be reglued once per race day.

Timing when weight gets to the tires is the key to curing traction rolling.
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Old 01-12-2010, 10:21 PM   #67
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Originally Posted by Lenman73 View Post
If you are not using droop screws, limiters indeed will change your droop. Think about it. If the screw limits the down travel of the suspension arm, a limiter inside the shock will also limit the amount the suspension will travel down. In this case more droop will = less internal limiters. This is how I have to do it on my TC. I went to more droop for the reason you mention above. So the tires will be on the track longer while the chassis rolls. For my particular case, more droop travel helped.
That is entirely correct. My bad.
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Old 01-13-2010, 06:47 AM   #68
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Originally Posted by Greg Sharpe View Post
In a last ditch effort, I glued the sidewalls AND began undoing all the changes I had made to cure the traction rolling. Whalla! The car is now capable of going 3/10ths faster per lap! The only downside to the glued sidewalls is that they actually build grip over the course of the day and need to be reglued once per race day.

Timing when weight gets to the tires is the key to curing traction rolling.
What sort of things did you undo, in other words what did you do initially to try to get rid of grip roll?

Thanks
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Old 01-13-2010, 07:38 AM   #69
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all the replies so far seem to point towards the same end goal: take steering away from the car to cure traction rolling

stiffer dampening (slows down reaction of steering)
less camber at the front (less steering)

etc etc
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Old 01-13-2010, 03:37 PM   #70
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Originally Posted by chris_dono View Post
all the replies so far seem to point towards the same end goal: take steering away from the car to cure traction rolling

stiffer dampening (slows down reaction of steering)
less camber at the front (less steering)

etc etc
Umm - Nope. Wrong assumption.

The goal is to let the chassis roll and work the way it was meant to without taking away steering.

Taking away steering is the last thing to do and in my book is right next to glueing the sidewalls. The last two things I want to do!!
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Old 01-13-2010, 05:55 PM   #71
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Originally Posted by sosidge View Post
If I have any observations, it is that if the car "snaps" into a roll, the car is probably too stiff. If it is "lazy" into a roll, the car is probably too soft.
Words of wisdom, it is so true... Thanks for the insight sosidge!
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Old 01-14-2010, 12:50 AM   #72
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Umm - Nope. Wrong assumption.

The goal is to let the chassis roll and work the way it was meant to without taking away steering.

Taking away steering is the last thing to do and in my book is right next to glueing the sidewalls. The last two things I want to do!!
it's not an assumption, I've looked through the thread and looked at what people are suggesting to cure it... most of the changes shown will give the car less steering.
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Old 01-14-2010, 06:38 AM   #73
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Quote:
it's not an assumption, I've looked through the thread and looked at what people are suggesting to cure it... most of the changes shown will give the car less steering.
If you're anything like me, once you've reached the point where grip roll occurrs every other corner, I think the amount of steering becomes the least of your worries

Having tried stiffening the car etc with no real improvment, I will try softening the suspension at Newbury this weekend (last time I was there I rolled at every other corner).

I'll let you all know how I get on.

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Old 01-14-2010, 07:00 AM   #74
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I look forward to hearing your results
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Old 01-14-2010, 08:09 AM   #75
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If you're anything like me, once you've reached the point where grip roll occurrs every other corner, I think the amount of steering becomes the least of your worries

Having tried stiffening the car etc with no real improvment, I will try softening the suspension at Newbury this weekend (last time I was there I rolled at every other corner).

I'll let you all know how I get on.

Skiddins

I hope you get it sorted Damien, your car was much much better at the last rug racers round when i saw it. Weirdly though, I've not had grip roll at either round i've been to.
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