Road 4's

[Vulgr]

I use PR4's and have not experienced the tires letting go at all. The only time I've actually felt them slip is when the tire needs replacing or I'm being ham-fisted with the throttle
I use the bike/tires for commuting and VERY spirited rides. You can definitely find the edge of the tire without it letting go.
(Note: I'm using PR4's, not the PR4 GT's)