Question About 4-Wheel Drive

[Pat McCarthy]

FYI: This isn't a competition robot design, it's going to be off-roading and other fun things.
I think that one CIM per side will still be enough if it was good in competition.

[Cory]

Originally Posted by Quatitos

You could always just use one sprocket on the output shaft of the transmission and then send that directly to one of your wheels. On this wheel you would place another sprocket on the opposite side of the wheel from the chain coming from the tranny. If you ran a chain between the two wheels like that they would end up being inline. The only bad thing is you use more chain this way.

Another downside is that if you somehow manage to derail the chain from the output sprocket, you've lost power to all wheels, instead of just one.

[team222badbrad]

Originally Posted by Cory

Another downside is that if you somehow manage to derail the chain from the output sprocket, you've lost power to all wheels, instead of just one.

Not necessarily, for the last two years we have taken #35 chain from the transmissions to the back drive wheels and then from #25 chain to connect the front and back wheels.

We have only had a few problems with the #25 chain for example last year while climbing up the steps at an angle we snapped the #25 chain on one side, but we still made it up the step with 3 wheel drive!

Just make sure that the chain connection from the transmission to the back wheel is properly tensioned and correctly aligned. You should not have a problem if you do that right.

I have included a picture of this years drive-train, it is not the clearest picture, but it will do.

[Quatitos]

Originally Posted by Cory

Another downside is that if you somehow manage to derail the chain from the output sprocket, you've lost power to all wheels, instead of just one.

We never had a single problem with this chain set up at all this year, but just in case, tension was checked before each match and we color coded all the master links for very quick access in case of emergency. Attached are pictures of the front and back wheels. Ignore the little bit of damage to the back wheel, that post next to it took a very big hit. Can you say two robots accidentally backed up full speed into each other? And just for clarification, the back wheel is the smaller wheel.

[Lisa Perez]

If by any chance you choose to get rid of the second driver sprocket, you can still power both wheels on the one side by setting up the tensioners and/or idlers in just the right spots. We used the idler sprockets this year and had no problems whatsoever with our drive train.

Since you're concerned about space constraints, this method saves a few inches width-wise because the wheel sprockets are on the same side and there is only one driver sprocket.