will a 33cc friction drive chew my tire???

welcome to the forum...i cant tell cause im a china gurl man...but rear setups seeem to be super practical...congrats.

If the roller isn't pressing down on the tire enough, it will slip and certainly will wear a tire quickly.
My setup is homemade. Springs pull the roller down; I started with a skateboard wheel roller and not enough spring tension. It was hard to tell that the roller was slipping, but it was and it wore down a tire in no time. Once I got the tension right, the tires last pretty long. Now I'm using a hard rubber roller made from a hockey puck. The statons have a steel roller, I think. If you gas it from a dead stop, it still should not slip, just bog the motor until you get up some speed. It's always a good idea to pedal a bit to get her going. Why wouldn't you? There's a price for being lazy (like my big gut).

I have a Staton 35 cc Robin Subaru friction drive with a 1 1/8" roller
Its works great and your worries are groundless

I weigh about 175 lbs and its flat around here. I have never been up any
hills and would like to get a 1 1/4" roller which would be the biggest you
would want to use.

It does not burn or slip on tires especially if you use the right tread
Your tires will get old and cracked before they wear out

It will slip in the wet but I don't ride in the rain and a puddle just
requires a little pedaling till the tire dries out

the roller should pressing on the tire just enough so that it doesn't slip

pushing it too hard slows you down
It is easy to get a feel for the right amount of pressure

I pedal to start and hit the thumb throttle at the same time and it moves off the line
pretty fast
I can motor off from a standstill with no roller slippage but I like to go fast
and it is a little hard and noisy on the centrifigal clutch

I have it on a 7 speed cruiser and leave it in top gear and can pedal on the
top end too to go about 28 Mph