speedo gear clarification

Brubaker

Brubaker

Well-known member
For a February '30, could either 9-34 or 9-37 be used? If the 9-37 was 'optional', when(or why) would it have been chosen or used? Thanks,Bruce
 
Bruce, I went back and reread your post and think I may have misunderstood your question. 9/34 speedo drive was used with 3.78 rearend gears and 9/37 was used with 4.11 rearend gears - which could be ordered in a pickup.
 
Thanks Larry. So it sounds like the 19-tooth is the correct speedo gear for a '30 Town Sedan(?). Appreciate your help.
 
By Feb. 30, most passenger cars would have been equiped with the 3.78 rear end unless someone special ordered a 4.11 rear end ratio which takes a 20 tooth drive gear The 19 tooth speedometer drive gear is correct for a 3.78; a 18 tooth drive gear was correct for a 1928 3.70 rear end. Some dealers sell the 18 tooth gear for a 3.54 rear end but this isn't really correct.

Ron

Ron
 
The very early cars had a 370 ratio rear end. (37\10). The pinion gear and the drive shaft were much different than the later 378 cars. The pre-load adjusting nuts were threaded onto the drive shaft, not on the pinion gear sleeve. I believe the 18 tooth speedo gear was delivered with the 370 ratios. I have a speedo housing I took off an early rear end that has 10-37 stamped on it and it has an 18 tooth gear in it.

Tom Endy
 
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