9" ring and pinion question

Keith 944 · 10-24-2018, 07:45 PM

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!

Mark Yacavone · 10-24-2018, 09:04 PM

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.

mschafer · 10-24-2018, 10:07 PM

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.

Ralph A Powell · 10-25-2018, 06:42 AM

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

Quote:

Originally Posted by Mark Yacavone

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.

Keith 944 · 10-25-2018, 09:15 AM

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

10-24-2018, 07:45 PM	#1
Keith 944 VIP Member Join Date: Feb 2006 Location: Dela-where? Posts: 2,195 Likes: 1,162 Liked 1,885 Times in 578 Posts	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! __________________ KEITH MAYERS 2-1/2 X somebody Still many X nobody

10-24-2018, 09:04 PM	#2
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,820 Likes: 2,910 Liked 5,127 Times in 1,955 Posts	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. __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers

10-24-2018, 10:07 PM	#3
mschafer Junior Member Join Date: Oct 2014 Posts: 44 Likes: 0 Liked 13 Times in 9 Posts	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.

10-25-2018, 09:15 AM	#5
Keith 944 VIP Member Join Date: Feb 2006 Location: Dela-where? Posts: 2,195 Likes: 1,162 Liked 1,885 Times in 578 Posts	Re: 9" ring and pinion question Thank U guys, just like that TH 400 thread I’m learning something new every day __________________ KEITH MAYERS 2-1/2 X somebody Still many X nobody

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