PDA

View Full Version : Front Roll Center



musolino21
09-26-2020, 12:42 PM
If a car does not respond well to common adjustments, can moving the front roll center be an "at the track" adjustment for tight or loose handling? Specifically, raising or lowering the RF upper control arm on the frame to relocate the RF instant center?

I understand body roll will react as well.

billetbirdcage
09-26-2020, 03:30 PM
If a car does not respond well to common adjustments, can moving the front roll center be an "at the track" adjustment for tight or loose handling? Specifically, raising or lowering the RF upper control arm on the frame to relocate the RF instant center?

I understand body roll will react as well.

Do you mean any changes don't really seem to effect the car? Or just not in a positive way?

Control arm adjustment:

For sure not a common adjustment. IMO that is more a track to track deal then a typical thru the night adjustment.

musolino21
09-27-2020, 09:46 AM
Hi Billet, I hope all is well. And correct... If nothing is binding and the car, just say, has a tight condition and doesn't respond to the adjustments. I was curious if adjusting roll center can help the car to turn.

billetbirdcage
09-27-2020, 05:22 PM
Hi Billet, I hope all is well. And correct... If nothing is binding and the car, just say, has a tight condition and doesn't respond to the adjustments. I was curious if adjusting roll center can help the car to turn.

Stop and think where the RF instant center is on a typical LM today? In the dynamic state and the limited range the RF operates in, the RF instant center is generally between the inner rod end of the lower arm and the RF lower shock mount. That being said how much are you moving the RF instant center if you move the upper arm 1" either way? it's not going to be much different as far as the actual roll center.

What I'm pointing out is the roll center isn't what is going to make the difference, it's the camber gain and if the RF needs more or less camber to maintain maximum traction. Then on a side note, if the camber isn't correct and the tire doesn't have max traction: Why would you want to change it back and forth? I would keep it at max traction and adjust the back of the car to adjust the car thru the night.

I hope that makes sense.

To explain or go into more detail about your issue or what else it could be, I would need a ton more info on the issue you have. But to be honest if the car doesn't seem to respond to changes. there is another issue somewhere? Check the car out for cracks in the tubing, I would think the frame is flexing a ton for some reason and thus changes are hardly noticeable.

I think you probably still have my number

musolino21
09-28-2020, 04:03 PM
I appreciate it, yes I do have your number. Thank you.