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Author Topic:   roll center questions
justin
Member
posted August 07, 2002 05:54 PM
I know what measurements to take to find my front roll center but what's the easiest way to apply these measurements to find the roll center? Should I string the car, draw it out on some paper or what? Also, I drive a 75 camaro, so if I need to raise my roll center what ball joints should I use. I know afco sells the 20032-1 ball joint but from what I gather it is for a metric car. Will it work on my camaro or is there a different one I should use? Sorry if the post sounds confusing. Thanks again.

Justin

gahainsey
Member
posted August 08, 2002 01:36 PM
roll center height is determined by drawing lines from the base of the tire thru the instant center of the suspension arms. Where these lines cross is the roll center. The 20032-1 is an upper ball joint that increases the angle of the upper arm. This helps move the roll center higher. The upper A-arm must be modified with a grinder and drill for installation. The 20038-1 is a taller lower joint that helps more. To use it in a Camaro, cut the old ball joint socket out, then weld a sleeve availble from AFCO into the control arm. Then press another sleeve then finally the ball joint into place. The 20038-1 has a larger taper than the stock joint. The spindle must be reamed with a 2 inch per foot reamer to accept the new joint. Not many racers go to all this hassle, but it is worth the aggravation. raising the front roll center decreases the cars leverage on the front spring giving less body roll per any given spring rate. It also helps the right front camber change curve.


gahainsey
Member
posted August 08, 2002 01:36 PM
roll center height is determined by drawing lines from the base of the tire thru the instant center of the suspension arms. Where these lines cross is the roll center. The 20032-1 is an upper ball joint that increases the angle of the upper arm. This helps move the roll center higher. The upper A-arm must be modified with a grinder and drill for installation. The 20038-1 is a taller lower joint that helps more. To use it in a Camaro, cut the old ball joint socket out, then weld a sleeve availble from AFCO into the control arm. Then press another sleeve then finally the ball joint into place. The 20038-1 has a larger taper than the stock joint. The spindle must be reamed with a 2 inch per foot reamer to accept the new joint. Not many racers go to all this hassle, but it is worth the aggravation. raising the front roll center decreases the cars leverage on the front spring giving less body roll per any given spring rate. It also helps the right front camber change curve.


justin
Member
posted August 08, 2002 06:06 PM
I know what measurements to take to find the roll center but what I need to know is should I run string through the pivot points and then run a string from my tire to the instant center or is there a different way to do it? I've heard of some people plotting it out on some paper. Thanks for clarifying the ball joint issue for me. If I do need to raise my roll center should I just replace the lower ball joint or both the upper and the lower?


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