Issues with Vex clamp on gearbox and 4 inch wheel

If you use a gear that is almost as large as the wheel's diameter, then of course you're going to have very little ground clearance. Two factors to always consider: The wheel will always dip into the carpet a bit, and the field is never perfectly flat, so there will be some bumps and ridges. Try using a 13:70 gear spread. The 72T gear has an outer diameter of 3.7" (radius of 1.85"). The 4" wheel has a radius of 2". That means on a perfect surface with a perfect setup you should have 0.15" of ground clearance, which in competition condition is still very little. Combine that with about 3/32" of carpet deformation and about 1/8" of bumps and ridges on the field (those two numbers being very generous guesstimates), and you'll find yourself with negative ground clearance (aka your gear touching the carpet).

[steelerborn]

Of course I understand all of the math behind what is going on, the 13:70 is one I was looking to switch to as well. And probably the easiest to do.

Like I said we had very little wear on our wheels just surprised to see Vex suggest a reduction that gives you maybe a day of driving then all of the wheels would need to be replaced. This is the first year I have used vex mecanum wheels and they so far are not holding up well.

I would like to hear about other teams that are using the same setup and see if they are experiencing similar troubles.

[steelerborn]

I don't believe vex has 70 tooth (I thought they did) so probably the 64 tooth will have to work just need to find the correct gears that will still provide a good mesh in the clamping gearbox.

[R.C.]

Originally Posted by steelerborn

I don't believe vex has 70 tooth (I thought they did) so probably the 64 tooth will have to work just need to find the correct gears that will still provide a good mesh in the clamping gearbox.

http://www.wcproducts.net/gears-w-versakeys

Not found under normal hex bore but with versakeys.

[steelerborn]

Awesome, going to probably order these later today.