Smallest SS Gearbox - COTS or Custom?

[jkelleyrtp]

Originally Posted by Joe Johnson

11:72 in one stage is not your problem. Tooth strength is the problem and you can build 12:72 gearsets that will fail on your first crossing and others that will last the whole season with nary a complaint.

What is the face width of the gears involved? What Pitch? What is the size of the wheel you are going to be driving with that 72T gear.

By the way, chain done right can be many many times stronger than gears (largely do to the fact that multiple teeth share the load). Can you fit a stage of #25 chain? 11:72 is fine in one stage of chain (~1"OD to ~5.9"OD)

Dr. Joe J.

I'm just poking around at the Vexpro SS. Unfortunately it seems as if a 1:7.52 isn't enough (we're looking for around 10fps with 6" tire)

So perhaps a 14:72 gear reduction then compensate with a 15t to 32t sprocket reduction. Vexpro gears are 1/2" wide with 20DP and a 14.5 pressure angle.
Are you confident this will hold up?
Although I would prefer to do most of the reduction in the gearbox if we were to direct drive any of the wheels.