pic: 968's 2006 practice bot chassis

i could never understand how the wheels stay on. could someone please explain this to me

We use snap rings to hold the wheels on.

You can see this here, sort of. There’s a groove in the shaft outside the sprocket. The snap ring expands to fit over the shaft, and then contracts when it is seated in the groove, and then keeps the wheels/sprockets from sliding off.

For some reason I can’t edit my post. Here’s the right link

but how is the wheel attached on the other side

I believe that the sprocket is on the other side. It’s a live-axle setup, so the sprocket is attached to the axle via keyway or hex, probably with a setscrew to keep it from sliding sideways.

Exactly the same way. Both sides have hexes (that screenshot is of the 05 bot, and it used woodruff keys), and both sides have a snap ring groove in the shaft to retain the sprocket/wheel axially. They butt up against a shoulder in the shaft where the hex ends.

oh ok thanks now i understand