Traction Rolling - how to solve it
#31
Tech Fanatic
Thread Starter
The physics involved is you dramaticaly lowered the center of gravity and altered the balance of your car. So with a given setup, the suspension had to work more to transfer the additional weight. Also that weight was added as low as possible thus making it harder for one side or the other to lift.
As basic as it can be described you changed the amount of force required to lift a weight on a simple lever with the fulcrum being the wheels.
As basic as it can be described you changed the amount of force required to lift a weight on a simple lever with the fulcrum being the wheels.
I would also add the following
1) since the weight was added at the front of the car this will make the car slide more at the front (i.e. push) when near the limit and actually cause more oversteer when not near the lateral limits of the tires (a good example can be the middle of a slow tight corner)
2) Reducing traction rolling has a lot to do with getting both ends of the car to roll into the carpet the same amount. if the car was traction rolling because the front of the car would would not roll into the carpet as much as the rear, then adding the weight can help this.
3) In general I don't recommend adding weight to the car unless you are under the min weight limit, as additional weight will ultimately produce less lateral grip, less acceleration and less braking = slower laptimes.
Yeah..it was not available on the apple store for a while, because I was not aware you needed to buy a developer license every year to be able to sell an app on the app store. So it was not available for a few weeks late in 2013.
#32
Tech Regular
iTrader: (21)
2) Reducing traction rolling has a lot to do with getting both ends of the car to roll into the carpet the same amount. if the car was traction rolling because the front of the car would would not roll into the carpet as much as the rear, then adding the weight can help this.
#33
This is off topic but im kind of out of options mr guru I am looking to take out traction of my car with out changing the handling too much what would you suggest my role centers are all the way down I took camber out im not at -1 I went up 75cst in shock oil im running jaco blues what else should I do to reduce traction and not change the handling too much?
#34
Tech Master
iTrader: (8)
This is off topic but im kind of out of options mr guru I am looking to take out traction of my car with out changing the handling too much what would you suggest my role centers are all the way down I took camber out im not at -1 I went up 75cst in shock oil im running jaco blues what else should I do to reduce traction and not change the handling too much?
#35
Tech Fanatic
Thread Starter
This is off topic but im kind of out of options mr guru I am looking to take out traction of my car with out changing the handling too much what would you suggest my role centers are all the way down I took camber out im not at -1 I went up 75cst in shock oil im running jaco blues what else should I do to reduce traction and not change the handling too much?
When you say the roll centers are all the way down, can you clarify what you mean by that? Are you saying the roll center is low, and by this I mean you have likley a lot of spacers on the inboard upper link and the lower arms are as low as they can go inboard?
Also, why are you trying to reduce traction...what is the issue you are hoping to resolve by reducing traction....you mention this is off topic, so I assume you are not trying to fight a traction roll problem.
#36
Hi
When you say the roll centers are all the way down, can you clarify what you mean by that? Are you saying the roll center is low, and by this I mean you have likley a lot of spacers on the inboard upper link and the lower arms are as low as they can go inboard?
Also, why are you trying to reduce traction...what is the issue you are hoping to resolve by reducing traction....you mention this is off topic, so I assume you are not trying to fight a traction roll problem.
When you say the roll centers are all the way down, can you clarify what you mean by that? Are you saying the roll center is low, and by this I mean you have likley a lot of spacers on the inboard upper link and the lower arms are as low as they can go inboard?
Also, why are you trying to reduce traction...what is the issue you are hoping to resolve by reducing traction....you mention this is off topic, so I assume you are not trying to fight a traction roll problem.
#37
Tech Regular
how can you have too much traction when you don't traction roll? If it's too nimble for you, you can also reduce dual rate
#38
Glad to see you posting again Martin. Love the app! Even use it offroad for escale and etruggy, as long as the track being blown out isn't my biggest concern. (Need an offroad workbench app!)
#39
#40
Tech Addict
iTrader: (2)
I've been battling this for some time now and could not wrap my head around why so many folks say you must soften the car up. In my head I had always looked at traction rolling as a direct result of too much roll.. limit the roll, limit the tip. Well, it's not that simple I don't think. The physics in carpet racing is very different due to what I might call traction/weight ratio. In the 1:1 world you could stiffen the car up to the point where you limit mechanical grip enough that the outer tires slide because they don't receive enough load. We have so much grip indoors that just doesn't happen, plus the speeds we race at aren't high enough to slide the car (albeit arguably) even if it is set up stiff. I believe there is a correlation between lateral load, vertical load and traction. When grip gets really high we essentially need less mechanical grip to get the car to turn at speed. The problem I think is that in doing so (stiffening the car), we are increasing lateral load and decreasing vertical load on the tire. This is a recipe for even snappier t-rolls. Theoretically, one may be able to stiffen it to the point it is able to break traction, but now you may have a setup that is quite skatey at the limit and just difficult to drive. If you go the other direction and soften the car I think what is happening is that you are effectively decreasing lateral load and increasing vertical loading of the tire (even more mechanical grip). I think it's the balance of this loading that is important here. However, because the car is sprung softly and the roll centers are very low, the chassis has a lot of leverage and less resistance to roll so you still need to limit it otherwise it'll still tip. Now one may be looking at a bit more ARB and things of that nature. Basically, instead of looking for ways to utilize the available traction in an energy efficient manner, we may need to look for way to waste it. By keeping the car softly sprung we are creating more mechanical grip that we actually need, but the direction of the loading may be what we need to keep the car from flipping over.
#41
Tech Adept
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How weird Martin.
I just posted a recommendation to get your book on another thread today for someone looking for a source of good setup information. Had no idea you were on this site. Also had no idea there was an app. Is there one for us non Apple folks?
I just posted a recommendation to get your book on another thread today for someone looking for a source of good setup information. Had no idea you were on this site. Also had no idea there was an app. Is there one for us non Apple folks?
#42
Um my arms are as low as the can go to the chassis I am running no spacers under my camber links im trying to reduce traction because I lost .2 off a lap and other guys could make changes to take more traction out of their car I cannot as of yet this was for the 3rd and main event its just slow and has too much tracrion in general no traction rolling
You need to define where this extra grip is causing a problem before others can help.
Skiddins
#43
Its one of the unexplainable things its working correcrly the car its steering fine its working great at the beginning of the night and as more traction gets layed down the car just starts feeling "stuck"
#44
Tech Master
iTrader: (15)
I've been battling this for some time now and could not wrap my head around why so many folks say you must soften the car up. In my head I had always looked at traction rolling as a direct result of too much roll.. limit the roll, limit the tip. Well, it's not that simple I don't think. The physics in carpet racing is very different due to what I might call traction/weight ratio. In the 1:1 world you could stiffen the car up to the point where you limit mechanical grip enough that the outer tires slide because they don't receive enough load. We have so much grip indoors that just doesn't happen, plus the speeds we race at aren't high enough to slide the car (albeit arguably) even if it is set up stiff. I believe there is a correlation between lateral load, vertical load and traction. When grip gets really high we essentially need less mechanical grip to get the car to turn at speed. The problem I think is that in doing so (stiffening the car), we are increasing lateral load and decreasing vertical load on the tire. This is a recipe for even snappier t-rolls. Theoretically, one may be able to stiffen it to the point it is able to break traction, but now you may have a setup that is quite skatey at the limit and just difficult to drive. If you go the other direction and soften the car I think what is happening is that you are effectively decreasing lateral load and increasing vertical loading of the tire (even more mechanical grip). I think it's the balance of this loading that is important here. However, because the car is sprung softly and the roll centers are very low, the chassis has a lot of leverage and less resistance to roll so you still need to limit it otherwise it'll still tip. Now one may be looking at a bit more ARB and things of that nature. Basically, instead of looking for ways to utilize the available traction in an energy efficient manner, we may need to look for way to waste it. By keeping the car softly sprung we are creating more mechanical grip that we actually need, but the direction of the loading may be what we need to keep the car from flipping over.
(static weight*center of gravity*g-forces)/track
With more traction compound laid down in the track, the faster you can corner. Of course, higher corner speed means more weight transfer and therefore more likelihood of the inside wheels lifting, bicycling, and then flipping over
So if you can reduce static weight (which we probably can't), lower the cg (difficult because of ride height minimum), go through the corner slower (why?), or increase the track (a possibility), you'll reduce weight transfer.
Stiffening or softening the car doesn't affect how much weight transfers. It affects how much the car will roll/ lean. If it is too stiff, the car stops rolling before the weight has all transferred. At that point the inner wheels lift and away we go. If the car is too soft, it'll just be too "stuck" and scrub corner speed. The odds of the suspension totally compressing because of a soft setup are almost nil.
#45
Well to affect weight transfer, and lower CG in turns you'll have to lower your droop significantly... Remember the Car has to still be squating down all the way through the turn long enough so you can exit the turn without traction rolling: too stiff a setup makes the Car not squat enough through the turn(early traction roll), and too soft a setup makes the Car squat too fast and bottom out (late traction roll)....