9" ring and pinion question
 

I am looking for a replacement gear set for my 9" ford. My question is I see a 4.56 and a 4.57 ratio listed. Why is there such a close ratio offered, and what is the difference, advantage or disadvantage to using one over the other? I guess I will also ask what brand everyone recommends and why? Thanks!

Re: 9" ring and pinion question
 

Keith, The original Ford replacement gear sets were 4.57. (7, 32)
Somewhere along the line , someone decided to use the GM style of 9, 41.
Maybe one of the engineers here could tell us which one would be stronger..theoretically, anyway.

Re: 9" ring and pinion question
 

I run a US Gear 4.57[pro gear] from Strange, part # RPO7990457US with 35 spline pinion, easy to set up, I had a Richmond 4.57 in car before that was developing a abnormal wear pattern and I called Strange, they recommended the US Gear and when I received it and compared the two I'm glad I bought it.

Re: 9" ring and pinion question
 

The 7/32 is less teeth on each gear = stronger teeth.

Re: 9" ring and pinion question
 

Thank U guys, just like that TH 400 thread I’m learning something new every day