Tire Sizes

Hey All,

Going to replace the stock Dunlop's on my WR and have decided on the Michelin M12's. Problem is they don't come in the same size. The Dunlops are 80/100 21 Front and 110/100 18 rear. What is the closest Michelin size. Looks like the only Michelin front is 90/90 21 whats the difference? Rears come in 90/120, 80/120, 80/130, and 70/130. Nothing rubbing with the factories, want to keep it that way. Thanks in advance.

Michelin comes with a rear 80/140 18. Big fat wide bugger. That's all I run.


I totally agree with FTD. Go with the 140/80 - 18. It is larger than the stock Dunlop rear but does fit very well. You may also want to consider going with the S12 on the rear instead of the M12 - especially if you do more sand and dirt than rocky trails. It is extremely durable and really hooks up.

You can't go wrong with either choice.

Mine came with 90/130-18 Michelin from Yamaha. Very, very nice tires! :)


The Michelins do run in different sizes. I have the M12 90-90-21 on the front and it is the same size as a Dunlop 756 80-100-21. The M 12 is a great tire on front, when the 739 goes I will add one to the rear. I think the 130 is correct for the rear.

Scroll down this page tire size . It helped me chose the 90/130 tire.

I think the M12 rear only goes up to a 130, where a S12 goes to a 140

Thanks everyone for the input. Tires on order. Took advice and getting the 140/80-18 S12 Rear. Didn't think about when I ordered them but will I NEED new tubes? Also ordered couple tire irons, been a long time since I changed a motorcycle tire.

Michelin comes with a rear 80/140 18. Big fat wide bugger. That's all I run.


I can?t understand why do you fellas run so big tires? I know from personal experience they offer some stability in rocks/stones terrain, but everyware else narrower tire offers tons of more traction. I had 130 then I went to 120 and now I'm at 110. GREAT traction!!! I think you should try it. I weight 95kg and I always outdrag my ridding buddies because of the narrow tire. Try it if just for once and you will never put this old fat tire again.

The S12 90/90/21 is the same size as 80/100/21

and 130/90/18 is the same size as 110/100/18

I don't know why the numbering system is off, but they come with stickers on the tire showing the actual size. :)

Tires came in yesterday, took me 2 hours and a few layers of skin an considerable blood letting to get it on but I did. I needed a break before mounting the rear so will try that tomorrow. wr250rr you're right the S12 140/80-18 has a big yellow sticker saying 120/100-18. Go figure. Riding with the M12 front today and I have to admit the front end hooked up. Typically the front end would wash out a few times. NONE today. Sabin - a personal kind of thing but I thing bikes don't look right with a small rear tire. Kind of like a truck doesn't look right without big tires. I don't doubt any of your statements about traction and weight. Can't wait to put that big sucker on. It looks mean just sitting in the corner of the garage. Think I'll have a few cold ones to settle the nerves before attempting this change :) Again thanks everybody. This forum ROCKs!

I am about to order my first new set of skins for my WR. Here in N. FL ride mostly in soft deep sandy conditions. I am thinking about the S12 for front and rear. I have never changed a motorcycle tire before, so my question is who long it took, and do you think it would be worth paying the 50 bucks to have them mounted and put back on the bike? Also did you end up putting in another tube or did you just stick with the one you had?


I scratched my rims trying to change mine. Changing a tube is much easier than changing the whole tire. I got the old tire off, but, I could not get the new tire on. Getting the first part of the tire over the rim was impossible for me. I advocate just taking the wheel off and taking it in to change the tire.

Did you use some water and soap mix? It helps a lot! There was some tire changing thread, try the search function.

It is not big deal at all, and you will be prepared on the trails. We need half an hour to repair a flat on the trails.


Have you tried the Michelin x-11? supposed to be the awesome setup. I have read numerous reports on this tire, and am really close to trying it. I guess I am in the realm of "bigger is better", but in this case I hear it is not true! :)

tetfsu, it took me about 3.5 hours total front and rear. It would cost me 30 bucks here to have them done. Between the bead locks and getting the darn valve stem back in the hole it was a BEAR! Next go around I will pay it I think. Save the tire changes for emergency only. I used the same tubes. Actually pinched the rear and patched it and stuffed her back in. Only because it was Sunday and couldn't get a new tube. I have a spare in the truck now incase the patch doesn't hold on the trail.

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