I tried a Michelin M12 tyre on the rear of my YZF450 it was like 130 fake width which is like 110 true sizing compared with other brands.

Seen: http://www.gofasters.com/images/m12.jpg

Anyways it was totally crap! Pretty much fell apart on me after two half day trail rides!

Now I have gone a Bridgestone M404 120 true width so a nice meaty tread patten and only just fits in the frame due to its width. But my god! the traction and the wheelies! Its all coming back to me actually felt like I could start to control my 450 again.

Seen: http://www.crfsonly.com/catalog/imag...stone-m404.jpg

Im not sure how true it is but the shop was saying this tyre was designed for 450's. And looking at it after one ride its using 4 knobs wide when rolling in straight line and cornering starts to use the very outer knobs. My Michelin was only using the two middle knobs in straight line hence the less traction.

Just thought id share my findings with other 450 owners