S2000 tire physics question... need an answer.
Joined: Jul 2002
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From: San Diego, CA
Originally Posted by jedwards,Aug 1 2005, 04:30 PM
Well you're right that underinflating creates a larger contact patch but since Billy is talking about 'moments' he's referring to the radius of the tire. Moments mean that something with a 2 lb push on the end of a a 2' member (here comes Mikey to explain what i mean by 'member') has the same effect at the other end as a 4 lb push on the end of a 1' member.
Hence I'm trying to increase the diameter not the patch.
Hence I'm trying to increase the diameter not the patch.
I'm an idiot, I didn't read Billy's post properly. 
Joined: May 2001
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From: Nowhere
Originally Posted by WestSideBilly,Aug 1 2005, 03:21 PM
Left tire (new) has a rolling diameter of 24.9", right tire (3/10" tread left) has a rolling diameter of 23.5". Under throttle the left tire is pushing harder (since the tires are going nearly the same speed) and making the car veer right, when you lift the left tire is dragging harder and pulling the car to the left. Think of the tire as a moment arm, the left tire has a 6% greater 'arm' (by virtue of being 7/10" larger radius). Granted, the LSD should accomodate some of that, but that's really not what the LSD is for.
The right rear should be replaced immediately before any damage to the limited slip can occur.
The right rear should be replaced immediately before any damage to the limited slip can occur.
The LSD is designed to prevent slipping, by sending more torque to the wheel with more grip. With the right wheel being considerably smaller, the LSD is going to act as if it is slipping (it is spinning faster to go the same distance), and send more torque to the left wheel (exactly the opposite of what you want in this case). The potential for damage comes from the LSD having to constantly be rotating, no big deal for short distances but over a few hundred miles the accelerated wear is a definite problem.
Decelerating (as far as I know) is essentially the reversal, as the LSD is trying to compensate for the apparent slip by putting more engine braking force to the left tire.
Jack - you could probably get away with that for a while, but due to the disparity, you'd probably have to run something like 23 lbs in the left and 42 in the right. The damage to the tire (uneven wear) would be worse than the damage to the diff.
Thread Starter
Joined: Jul 2001
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From: This is not my house!
Billy it's possible what's causing me to 'feel' the effect is in fact the LSD. It may be driving the pull to the right and left on accel and decel respectively.
No doubt though it's the wear.
No doubt though it's the wear.
