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Unread 24-06-2016, 09:58
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Re: pic: Another Belt-In-Tube Drivetrain

Quote:
Originally Posted by Ty Tremblay View Post
Thanks. What size tubing do you use for your rails? is it 2" tall? If so, what kind of drop are you using and do you run into the issues that Joey mentioned above?

Agreed on the ThunderHex. we ran Thunderhex on our chain-in-tube this year and loved it. I just already had the hex bearings imported into OnShape.
Shaker's drives haven't been welded for the past several years, so we have used 3" tubes to allow ample rivet clearance. In flat field games like 2014, we can use 4" wheels with 3" tubes no problem. In other years we had to switch to 6" wheels for extra clearance. With the 3" tubing, 1/8" drop was just fine (if anything a little more than we needed in 2014). If we went to 2.5" tubing or smaller we would have to stagger the drop or even switch to a zero drop drive, sanding outer wheels down to a smaller diameter if we needed to add drop after the fact.

The designers on the team are looking into ways to use smaller tubes in future drivetrains, to save weight and to allow adequate ground clearance with 4" wheels. 2.5" tall tall tubing, with rivets staggered to avoid the belts and pulleys, are a possibility. Experimenting with smaller tooth count pulleys is another option, albeit a risky one. 21T pulleys have a number of teeth divisible by 3 for easy machining, and they allow JUST enough clearance for a 2" tall tube if you stagger the rivets, but without testing I can't be certain they would be robust enough.
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