1935 Ford Diff Ratio Advice
 

Hi,
Can someone give me some advice on working out Diff ratio, my current setup is way too low geared so im rebuilding the diff with a new crown and pinion gear set (I dont know the current diff ratio)
Some details below :
In have 1935 ford coupe ,currently building a new flathead engine for the car which will be a stroker engine 59a block
Running a 1939 Ford 3 speed
Running the standard Banjo diff
Wheel size is 15" with a set of Coker 560-15

Can someone advise of a good ratio for this setup or how to calculate what ratio is needed.

Thanks

Re: 1935 Ford Diff Ratio Advice
 

The car I require advice on.
Thanks

Re: 1935 Ford Diff Ratio Advice
 

Welcome, great looking ‘35, does it have a rumble seat?.
See this link about ratios
http://www.advanced-ev.com/Calculators/TireSize/

Re: 1935 Ford Diff Ratio Advice
 

graeme, sorry I can't help with the ratio, but I sure love your car.. Very Nice !!! Welcome to "The Barn !!

Re: 1935 Ford Diff Ratio Advice
 

My view of ideal for your Coupe s a Columbia 2 speed with a 4:11 - best of both worlds in one rear!

Re: 1935 Ford Diff Ratio Advice
 

I put 3:54's in my '37 w/ 27" diameter rear tires. My engine is a stock 1940 85 hp.
This ratio is much better than the 4:11's that were in it! I can now cruise @ 60 mph turning 2600 rpm. 65 mph is about 2800 rpm, but it's "sweet spot" is 60 mph. This car has a 9" clutch & the moderate hills in my area are no problem from a dead stop. - F F

Re: 1935 Ford Diff Ratio Advice
 

I have a 4:11 in my stock '36 roadster with a correct (36) Columbia. The car will do 60 - 65 without effort. Very happy car at those speeds.
If you don't want the suffer the expense of a Columbia, I'd suggest a 3:78. That's what is in my '39s and '40s - all stock cars. Very nice ratio for all types of driving.

Re: 1935 Ford Diff Ratio Advice
 

Aren't 5.60-15 tires a little small (especially in the rear)? That's the size that came on Volkswagen Beetles.

Re: 1935 Ford Diff Ratio Advice
 

Yes, 5:60 x15 tires are only 25.88 inches in outside dia.
Consider changing to a larger size tire. For instance:
https://www.summitracing.com/parts/C...RoCy_UQAvD_BwE

Re: 1935 Ford Diff Ratio Advice
 

If want to stick with the 5.60-15's, I'd go with a 3.54 ring and pinion.

Re: 1935 Ford Diff Ratio Advice