I switched from staggered 17"; 225 f, 255 r to a 19" fitment using 235 f and 275 r. The grip level doesn't seem much higher but the tramlining is virtually gone and the ride actually improved, quieter and softer.
Previous tires were top of the line Bridgestone REO50A non RFT. A highly rated tire that I did not like at all. The 19's are Falken 452's......not a top line tire but they actually work better on my Zed.
I think it's not the size but the individual tire that's the key. PS2's, Goodyear F1's, Kumho's and Falken all seem to be sensational on Z4's
Oh....the huge 275's on the rear.......they look VERY nice.
