I am quite new to riding. My '01 zx6r has Dunlop d207's on it and I am quite satisfied with the grip. On holiday I've been riding my bro's '00 CBR600F and with the same tires, I had almost no grip compared to my bike. Ok, they were worn just a bit more than the ones on my bike, but what can you suggest for somewhat dirty roads for my bro. By the way playing around with tire pressure, we came to a bit better grip, but giving throttle or shifting down while braking for a red light results with a spinning or blocking rear on his bike. While he is in Turkey where the temperatures over there are quite higher, does it effect the grip results? Any comments?