Ultra grip style pulley

[metalman302]

Do the pulleys with the grip slots actually work or is it just marketing hype?

Also dies overdriving the lower increase your chances of slippage by much? Or is it mostly just upper diameter?

 

[prostkr]

As far as slip goes the bigger the upper and lower the better. Pick a target boost and I can recommend sizes. In my experience pulley style doesn't matter unless you use the right belt. A straight rip pulley will work well with a gator back notched belt. A grip slot pulley will work equally well with a gates straight ribbed belt. Its splitting hairs, they both can work well if you take time to set them up right.

 

[NateTermi]

Do the pulleys with the grip slots actually work or is it just marketing hype?

Also dies overdriving the lower increase your chances of slippage by much? Or is it mostly just upper diameter?

If you run your finger over one you can feel the slots grabbing your finger, so yes I think they work.