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Front Tire Size Change

Posted: 10:45 pm Apr 18 2007
by Jeb
Got a chance to pick up either a Michelin S-12 or M-12 front tire, new, for a great price . . . but the tire size "ratio" is 90/90.

Any thoughts or experiences on the tire size change from the 80/100? I guess I'm lookin' for comments on what I would expect in terms of changes in performance/feel . . .

Which of my two choices might be better for 75% woods/trails, 25% mx track? How about wear?

Posted: 01:29 pm Apr 19 2007
by skipro3
The more the S-12 wears, the better it grips in my experiance. I used to break them in on asphalt with hard front braking stops to get them rounded a little. Sounds strange, don't it? Also, the S-12 likes lots and lots of weight on the front to steer fast without undercutting. Keep your weight well forward with this tire and you will be railing through turns!

Posted: 02:48 pm Apr 19 2007
by KarlP
I didn't like the M-12 that i ended up with when I got the KX front end. My S-12 went on the KX125 the front end came off, so I could do a side by side comparison.
I finally bought an S-12 for the KDX
For my conditions I like the S-12 a lot better, but that is just me.

Posted: 08:25 pm Apr 19 2007
by danfree
The S-12's were highly recommended to me as well. The stock tire size for my KDX is 80/100-21 for the front. 100/100-18 for the rear. Are there any issues with using a different size? i.e. 90/90-21 for the front and 120/90-18 for the rear? I don't understand the sizing either. Plus, I read somewhere else that Michelin vs Dunlop vs Kenda may use different measure points? That could make things a little confusing. Kinda like shoes. Sometimes I wear size 9, sometimes 10 depending on which brand.

Posted: 08:40 pm Apr 19 2007
by scheckaet
I just replaced the front stocker with a S12, no problem. On the michelin website (ormaybe rocky mountain) they show a chart with equivalence between brand, makes it easier to figure it out

Posted: 08:50 pm Apr 19 2007
by Jeb
Tire sizing differences . . .

I did some scrounging around and allegedly Michelin sizes include the knobs, apparently unlike other mfgs whose measurements use the carcass. So, if I've got this right, the Mich's are 90mm wide (including the knobs) and the sidewall height is 90% of the width (81mm). My current tire is 80mm wide - not including the knobs - with a sidewall height of 100% (80mm). If this is right, tire sizes are very similar . . .

and even if they were a smidge difference I wonder how much difference it would make anyway.

Posted: 01:19 pm Apr 20 2007
by xagentman
well, this sounds good and all but, what about those of us who are riding a lot of rocks, wet roots, and hard pack? will the S-12 just chunk into little bits?

I am running a Dunlop D952 and it has great hook up in the rear. I'm looking at running one in the front as well. anyone else have experinace with this tire?