One thing may be important regarding wear and heat Dougster..
Certainly the Cycleops has a swinging arm to bring the roller into contact with the tyre (i assume they all work the same way). I always set mine with the minimum amount of pressure needed on the tyre to avoid slipping, rather than just 'whacking it on'.
If you push too hard, it can slip, but its just finding the right amount of contact pressure. Perhaps it causes excess heat / wear if the contact pressures too high.