VAC Gear ratio

[Obsession]

On a 1947 VAC Case is the gear ratio differnt on a VAC with 34 vs 28 inch tires?

What changes the gear ratio?

 

[VACLee]

The bull/pinion gears are different. The parts book does not show different ratios for the disc brake setup unless you get into the VAI's. There are 3 different ratios availible for band brake setups(12/67,13/66,14/65). The 13/66 is what came in the disc setup. There were some VAC's equipped with different 2nd and 3rd gear ratios for DOT mowing tractors. Most of them also had the higher ratio bull gears. Appears they were actually using the VAI gear set instead of the regular VA set.

 

[Obsession]

Thanks for responding. I appreciate the help!

My VAC’s both having the old style disk brakes. Neither one of them is a VAI so more than likely they are the same. Right?

I am going to mark and measure both transmissions by turning the input shaft, hold one rear axle, and measuring the amount of rotation in all of the forward gears.