I can't remember who gave me this advice. When I was last looking for tyres for my Kawasaki Z1000, someone suggested I try a higher aspect ratio rear tyre (i.e. 190/55/17 as opposed to an original 190/50/17). The advice I was given said it would make the bike turn in more easily and sharper. Well after 2,000 ks on a tyre that size I regret the purchase. I've learned that the bike feels vague, not sharper, does not turn in any easier or quicker and in fact feels heavier. Also I have managed to get understeer on a few occasions which is off putting and shakes my confidence. I will be changing back to the original size very soon. .