I have used the MX51 on my YZ450F for some time now and it continues to deliver great traction and life. I tried the Bridgestone medium tire (400 series) and the grip is no where near where the Dunlop is. I ride tracks and desert and do some racing and these tires last a good amount of time. This is the only tire that holds the grip better on the bigger bikes. The only tire I will use, personally. You won't be disappointed!