[Oblarg]

Originally Posted by JoshD99

We are building a West Coast Drive chassis for our t-shirt robot. We have never done this before, but we think we know what we're doing. The only problem is that the gearboxes we're using, if we mount them directly to the wheel, will drag on the floor, as we are using 4 inch wheels. What can we do to fix this? Here are the gearboxes we're using http://www.vexrobotics.com/vexpro/ge...reduction.html

Thanks!

As you discovered, you're not going to be able to direct-drive off of that gearbox with 4'' wheels.

Your options are pretty straightforward - you can either use bigger wheels, mount the gearbox elsewhere and link it with belt or chain, or you can use a different gearbox. The COTS options that will work with 4'' wheels, as far as I know, are all two- or three-stage.

If you have the machining capabilities and really want a singe-stage reduction and direct-drive center wheel, you can make your own gearboxes. Be aware that the ratios you can get with a single-stage reduction and 4'' wheels might not be high enough for comfort in an extended pushing match with a heavy robot and high-traction wheels, so if you're looking to have pushing power you might want to go with a different gearbox anyway.

Edit: Upon re-reading, I noticed that this is a t-shirt robot, so pushing performance probably isn't too important. Still, the advice stands if you want to transfer this design to an actual competition robot.