MTFCA Forum

So I just got a 13 tooth pinion stamped with Ruckstell, 8501 13-40 20N on the front and LC.CO. ID24 along with another number that can't be read on the back.
Would this have been used with the standard 40 tooth ring gear or other? With 40 tooth, looks to be about 3.07 to 1. How common was this combination, I don't see a lot in the Ruckstell repair book from the club.

It goes with a rux ring gear. That gear has the offset you see in the 13-39 gear sets. No, it wont fit a stock ford 40 T gear.

Ok, buggers! Thanks

Before a thousand 13/39 gears were made post WW2, those were the usual "3 to 1" gears. Yes, they are not exactly 3 to 1, but that was what people called them. There were also some other companies back in the era that made 13/40, 13/39, 13/36, ten tooth pinions, and even a couple other unusual ratios.

The Ruckstell 13/40 gears were fairly good, but they sometimes had hardening issues resulting in a few teeth sometimes breaking on the outer ends.