Today I had a not so nice experience while riding: in a corner leaned over pretty close to the edge of the tires, the bike started sliding. I'm not sure whether it was both wheels or just front, but I caught it pretty easy. I was surprised how easy it was actually to catch it, but initially I was surprised it was sliding at all. The street was clean, no sand or dirt there and nothing that would indicate a slippy surface. I have done that corner on the F800GS with dragging parts on the road without issues before.
I think it was due to the Metzeler Tourance EXP front tire being already at the edge while the back still had a bit to go. Not sure what's wrong with this but so far I never had tires where the front was used up to the edge earlier than the rear - a sliding rear is much easier to control than a sliding front and I was always under the impression that tire manufacturers account for this.
On the F800GS I had Michelin Anakee II and had them easily to the edge on the rear but never fully to the edge on the skinny 21" front of the small GS. Not sure whether it's because of the different dimensions, but so far I don't have the best impression of the Tourance tires that are mounted on the R at the moment and will be happy to replace them once they are worn. At least they start sliding in a very controllable way, but an inexperienced rider might have gone down because of that. I had them slide a few times already and that was definitely after "roughing them up". New tires are slippery, I know that and deal with it appropriately but those are just a bit too slippery, even after more than 600 miles.
Next time I get tires I'll get pure road tires as about 99.9% of my riding is on tar. Continental Road Attack or Michelin Pilot Road 2 might be a good choice for my style of riding.