When grinding, especially on wide chisels and jointer blades, my gringing wheel slows down quite a bit. I don't think I'm putting too much pressure on the tools ( it doesn't seem to take much effort to slow the wheel). I tried a bit more belt dressing but it doesn't seem to help much. Any suggestions??
Rough the drive wheel up with a piece of 80 grit sandpaper, then apply a little bit more belt dressing. That will stop the slip.