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Unread 22-01-2012, 10:41
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AKA: Patrick Freivald
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Re: Chain/sprocket driven wheels of different diameters

Speaking from a position of never having done this before, I would suggest that you not do too much experimentation on a drive train during the build season, and instead save such prototyping for the off-season. There are simpler ways to get over the barrier, like extra off-set idler wheels in the front that are mounted higher so that they are not in contact with the ground.

Quote:
Originally Posted by EFastring View Post
We are looking at 10" diameter pneumatic wheels in the front and 6" omniwheels in the rear. We would like to run 4 wheel drive with a pair of CIMs running through a CIMple gearbox, output sprocket with a chain to the front 10" diameter wheels with a 60 tooth sprocket, and a chain to the rear 6" diameter omni's with a 36 tooth sprocket.

Is the potential for the front and rear wheels to try to travel at slightly different speeds (due to the diameter change of the pneumatic tire, etc.) going to be a big problem? My first thought is that the omniwheels are pretty slick and should slip to relieve tension if/when it builds up.

We could potentially run 4 CIMple gearboxs (one for each wheel) and let the motors do the load balancing, but it would be nice to have both motors power to the front wheels, and we would like to keep things as simple as possible.

Has anyone successfully (or unsuccessfully) run powered wheels of different diameters off the same chain (or chained together)?
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