1931 V12 REAR END GEARS

[Cord1930]

Hi.   I am looking at replacing the rear end gears in my 31 Cadillac V12.  Dose anyone have any suggestions that can get me to a 3.1 or maybe a 3.5 gear ratio that can easily bolt on.  Did anyone in the club make lower gear ratios, that may still be for sale.  Any leads appreciated.   Thanks

[Classic]

Phil Bray (ORF Corp.) was the go-to person for high-speed rear ends (Packard's, Cadillac's, Duesenberg's, etc.).  Unfortunately he passed away last April.  But you can contact his wife Carol at 734-676-5520.  I'm sure she will be able to tell you who has taken over Phil's business.  Be careful not to go to too low a ratio, which can cause startability problems, especially on hills.  85% of the original ratio is probably a good guideline, but in any event, not lower than 80%.  Others chime in if you have a different opinion.

[Classic]

Another option is to install an overdrive.  Gear Vendors is a popular brand.  https://www.gearvendors.com/custom.html
Some people prefer the R10 Borg Warner overdrive.

[Mike Baillargeon #15848]

I also thought of the overdrive route but, I think you'll have to do some monkeying around with the drive shaft tube to get it to work. 

But once its in, it will be the answer , you'll have those tall gears to get the 6000 lbs rolling and then shift to overdrive to cruse.   It does sound sweet!

Mike

[Bob Hoffmann CLC#96]

Guys,
When it comes to rear end ratios, things are opposite.
A high ratio is a low number.
A low ratio is a high number.
Tall gears are high ratio,
Stump pullers are low ratio.
HTH, Bob

[Wayne Womble 12210]

I have a stump pulling 4:90 if any one needs it. 

[Bob Hoffmann CLC#96]

Wayne,
Knock 20 % of the teeth off & turn it into a 3.90. LOL!
So... do you agree with my post?
Bob

[Wayne Womble 12210]

Bob, that would be how you write that number.   Written as 411 it would be high, but as 4/11 it would be low.    But we are talking about ratios 3/11 is a higher number than 4/11, but is that a lower ratio or not?

I agree with you, we always called a stump puller a low ratio.