Chains for 6 wheel drive

[dtengineering]

I'm a strong advocate for having at least one set of wheels direct drive off the gearbox.

I've just seen too many robots (including some of our early ones) limping around the field with one or both chains trailing behind them. Yes, you can build a gearbox/wheel chain link that will give you gear adjustment and will be reliable, but direct drive reduces the risk that you won't get it right.

We used the extended drive shafts and 14:1 gear ratio on an AM toughbox to drive these VEXPro wheels on our 8wd robot last year. You can see the gear link up in the attached thread. By turning the nylon rollers down to size we were able to get pretty perfect chain tension fairly easily.

http://www.chiefdelphi.com/forums/sh...highlight=1346

Once you've got the direct drive set up, then I'd only ever connect two wheels with one loop of chain. It just makes tensioning easier, ensures excellent sprocket/chain connections (lots of teeth in contact) and means that even if you lose one chain, you don't lose your entire drive system.

Remember... you might spend six weeks building a robot that will only get to play eight matches. You don't want to have one of those matches spent limping around the field with a busted drive train!

Jason