The Ford Barn

graeme_capon · 03-06-2022, 07:40 AM

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

graeme_capon · 03-06-2022, 07:44 AM

The car I require advice on.
Thanks

corvette8n · 03-06-2022, 07:53 AM

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

mfirth · 03-06-2022, 08:11 AM

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

PeterC · 03-06-2022, 09:08 AM

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

Ford Freak · 03-06-2022, 09:40 AM

Sponsored Links (Register now to hide all advertisements)

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

Kube · 03-06-2022, 09:59 AM

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.

tubman · 03-06-2022, 10:46 AM

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

19Fordy · 03-06-2022, 12:33 PM

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

Detonator · 03-06-2022, 06:48 PM

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

petehoovie · 03-06-2022, 07:05 PM

Quote:

Originally Posted by graeme_capon

The car I require advice on.
Thanks

03-06-2022, 07:40 AM	#1
graeme_capon Junior Member Join Date: Jul 2019 Posts: 6	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

03-06-2022, 07:53 AM	#3
corvette8n Senior Member Join Date: Jul 2010 Location: 36 miles north of Albany NY Posts: 2,954	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/

03-06-2022, 08:11 AM	#4
mfirth Senior Member Join Date: Aug 2017 Location: ohio Posts: 986	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 !!

03-06-2022, 09:08 AM	#5
PeterC Senior Member Join Date: May 2010 Location: Connecticut Posts: 855	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!

03-06-2022, 09:40 AM	#6
Ford Freak Senior Member Join Date: Feb 2013 Location: Pittsford NY. USA Posts: 1,096	Re: 1935 Ford Diff Ratio Advice Sponsored Links (Register now to hide all advertisements) 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 __________________ 1952 Ford F1 1965 Ford Falcon Sprint 2007 Ford Mustang GT

03-06-2022, 09:59 AM	#7
Kube Senior Member Join Date: May 2010 Location: Wisconsin, USA Posts: 9,012	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. __________________ "I can explain it for you. However, I can't understand it for you".

03-06-2022, 10:46 AM	#8
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,320	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.

03-06-2022, 12:33 PM	#9
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,950	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

03-06-2022, 06:48 PM	#10
Detonator Senior Member Join Date: May 2010 Location: Santa Cruz Posts: 391	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. __________________ Seabright Hot Rods