Need thoughts on backlash
 

We are replacing gears in a GM 8.5 inch 10 bolt. They are Richmond 4.88 and call for .010 backlash. We can get .012 and .008 with the shims we have now. This is a transbrake application in a 3300 pound car. What is an acceptable plus or minus from Richmond's .010 and would you use a tighter backlash with a transbrake? Thanks Doug

Re: Need thoughts on backlash
 

The pattern is more important than back lash, but back lash is better on the tight side, so long as it does not bind. Check to make sure that it does not have a spot that binds or gets tighter than 0.002-0.004, and you'll be fine at 0.008.

Re: Need thoughts on backlash
 

Alan, thank you very much as you just confirmed my thoughts. And thank you to Classracer for this forum, it has served me well and is an excellant tool for resources. Doug

Re: Need thoughts on backlash
 

I agree with Alan.....I use .004 at the tightest spot when checking and set the pinion so the tooth pattern is closer to the inside of the ring gear than in the middle in a drag race application. Under a load the pinion tries to move toward the outside of the ring gear which could cause chipped and broken teeth.