Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 10-20-2020, 03:23 PM   #1
Tootall
Junior Member
 
Join Date: Jun 2016
Posts: 24
Question identifying rear gear ratio in 1931 model A

I am looking to purchase a Model A chassis and it has a transmission still attached. Ii wish to know the rear gear ratio and upon looking on the Speedo, I found the numbers 9-34. I am assuming this is an after market or special rear gear ratio.
Could someone help me out?
Tootall is offline   Reply With Quote
Old 10-20-2020, 03:26 PM   #2
Kurt in NJ
Senior Member
 
Kurt in NJ's Avatar
 
Join Date: May 2010
Location: on the Littlefield
Posts: 6,140
Default Re: identifying rear gear ratio in 1931 model A

3:78
Kurt in NJ is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 10-20-2020, 07:21 PM   #3
Joe K
Senior Member
 
Joe K's Avatar
 
Join Date: Jul 2010
Location: Cow Hampshire
Posts: 4,174
Default Re: identifying rear gear ratio in 1931 model A

Quote:
Originally Posted by Kurt in NJ View Post
3:78
Yes, the 9-34 you found refers to the number of gear teeth in the rear differential. Different years, or more accurately have different ratios, this done by varying the gears.

My truck originally was 4.11. Now with high speed gears 3.54.

The speedo gears on mine are marked 9-34, but I mentally add a couple of mph. Now the proper speedo gears for the high speed rear are available.

You can confirm your ratio with your rear wheel (one) up on a jack, a starting crank, your transmission in 3rd gear, and understanding that a differential with one wheel held to the ground "doubles" the motion for the free wheel.

Joe K
__________________
Shudda kept the horse.
Joe K is offline   Reply With Quote
Old 10-22-2020, 01:13 PM   #4
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,351
Default Re: identifying rear gear ratio in 1931 model A

Sponsored Links (Register now to hide all advertisements)
Here’s info from an old post
Attached Images
File Type: jpg 030AC118-5E5E-4C55-BFC1-711FA1A7DD61.jpg (20.8 KB, 65 views)
Chuck Sea/Tac is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 10:21 AM.