Michelin S12 Tire Sizes?

Smit-Dog · Sep 10, 2002

Michelin S12 Tire Sizes? What About Tube Sizes?

Bike is a 2002 KDX 220R. I'm going to order a set of Michelin S12s, front and rear. The sizing chart on the Michelin web site does not appear to include any dirt bike sizes.

Stock front is a Dunlop Sports K490 80/100 - 21.
Stock rear is a Dunlop Sports K695 100/100 - 18.

Appears that the only front size available in the Michelin S12 is a 90/90 - 21. Is this fine for the KDX? Is this the only size offered?

The choices for the back are 120/80, 130/80, and 140/80 for 18" rims. Which should I get? 130 seems to be the general recommendation, but why not the 140? I'll be riding in mostly soft/sand conditions (northern Michigan).

Thanks!

KelvinKDX · Sep 11, 2002

I've been using the 120/80 for the rear.

Fred T · Sep 11, 2002

Yep:
get the 120/18 rear and the 21 front. Work great here in MI. Love 'em!

jeffw · Sep 11, 2002

When mounted the Michelin 90/90 21's look tiny compared to Dunlop 80/100 21's.

OLD-N-SLOW · Sep 11, 2002

They use different sizing thann most manufactures. a 120 is the same as a 100 dunlop. The 90/90 is the same size as the stock front. They just look different due to the design differences. By the way they work great. I use the
120 rear s-12.
Steve
P.S due a search on this, u will find lots of info on this.

Braahp · Sep 11, 2002

Use the 130 rear. You need all the meat you can get when attcking a muddy nasty hill. Works better than any tire I've tried so far.

dirt bike dave · Sep 11, 2002

FWIW, I put the 130/18" S12 side by side against a 110/18 Dunlop 756, and the Michelin is just a tiny bit smaller. If you prefer a 110 size tire on your KDX, get the 130 Michelin; if you like the stock size 100 rear, get the 120 Michelin.

m_champoux · Sep 11, 2002

I race with a lot of KDX (FMSQ) and almost everybody use the M12 in front combine with S12 for the rear tire. :)

I even heard that Shane Watt was using this setup.

I have a 130 for the rear tire and it's still grabbing after a season of races.

Still, the michelin is the best tire on any setup !! :moon:

Marty
KDX220R 2001

Smit-Dog · Sep 11, 2002

Sounds like the size for the rear depends on the type of riding terrain and personal preference.

I called Michelin customer service direct for a sizing guide, and they told me that they do not make a dirt tire for a KDX! :)

Fred: I like your reasoning about how a bigger tire is not necessarily a better tire (eventually found it in another thread). But why the 120/90 aspect ratio as opposed to the 120/80 aspect ratio?

Thanks for all the advice guys!

Fred T · Sep 11, 2002

Originally posted by Smit-Dog
Sounds like the size for the rear depends on the type of riding terrain and personal preference.

I called Michelin customer service direct for a sizing guide, and they told me that they do not make a dirt tire for a KDX! :)

Fred: I like your reasoning about how a bigger tire is not necessarily a better tire (eventually found it in another thread). But why the 120/90 aspect ratio as opposed to the 120/80 aspect ratio?

Bill
I feel that too much tire can be a bad thing not allowing for some wheel spin can be a problem. I don't think "we" Mi riders have that much of the wet snotty clay type riding to require less wheel spin. The sand can "eat" horspower and having a too big tire on it will rob you in some ways. Regarding the 80 vs 90 I know that Michelin has a soft side wall to absorb some shock and keep the tire on the ground more with less "bouncing" over smalll objects. I think thats the reason.

Thanks for all the advice guys!

70 marlin · Sep 12, 2002

smit dog go to lansing cycle they've a killer sale on S-12's! call ahead to make sure they have the sizes you want! aaron just picked a rear up for his kdx. I think out the door it was $60. also dunlop has a 773 that is just like the S-12, I love mine! and my dealership in jackson out the door for around $60. that K695 sucks big time no hook up! you won't beleive the difference!

Smit-Dog · Sep 12, 2002

Thanks Marlin - I did see the EE monthly specials on the S-12s a little while back browsing their site. The local KTM riders are lucky to have a dealer like that so close by.

I have a pretty good source for parts and accessories. The drive is about the same as EE (an hour), but the prices is great. Thanks...

- Bill

Smit-Dog · Sep 19, 2002

OK Guys -

I am picking up the Michelins S-12s today: 90/90-21 front and 120/90-18 rear. I removed the old tires last night, and am wondering if the stock tubes will work with the new tires (the tubes only have 125 miles on them).

Here's is what is printed on the tubes:

Front Tube (this appears to be OK for a 90/90 Michelin):
2.75 / 3.00 - 21
80/100
80/90
90/90
90/80
100/80

Tube Rear:
3.75 / 4.60 - 18
100/100
110/90
120/80

Since the tube does not specifically list 120/90, do I need to or should I get a new rear tube for the Michelin?

BTW - Everyone was right with the soapy water helping to get the old tire off. Made a big difference. For the new tires, I'm going to throw them in our 104 degree hot tub for a few minutes to help soften them up for stretching.

Thanks!

m_champoux · Sep 19, 2002

Don't waste your time with tube sizes, buy front tube for the front and the rear tires !!

Dirt Bike was suggesting this setup because you only have to bring one tube on the trail. It works for me ! :yeehaw:

Marty
2001 KDX220R

ktmracer · Sep 19, 2002

I think dirt bike was suggesting that in a pinch (literally and figuratively) you could use the front tube for the rear.

will

Fred T · Sep 19, 2002

Your stock tubes will fit fine. Some suggest to replace tubes every time you replace tires but I guess if you replace tires at least once a year and then replace the tubes you'll be fine. I've heard the Bridgestone HD tubes are pretty nice. For Air pressure with the Mich. tires here in MI I suggest about 10-12 LBS frt/rear. You're gonna love 'em.

gooby · Sep 19, 2002

i replaced my dunlops 80 100 21,110 100 18 with michelins 90 90 21,130 80 18 .different numbers but same size .ur gonna love the michelins dude

Smit-Dog · Sep 20, 2002

Thanks for all the tips guys. Finally got the new rubber on last night.

First impressions... the front looks like a spiky knife, and thinner compared to the stocker. Looks like it will really carve a corner. Overall both have bigger, deeper knobs, more of them at a side angle, and the rubber is softer compared to stock. Can't wait to try them this weekend!

This was my first tire change, so thought I'd pass on some feedback to help out any other newbies.

- I used two 15" tire irons, each with a curve and little lip at the end. Worked great, but wish I had a third to help hold the tire in place.

- I used an old plastic milk crate to set the rim on so as not to damage the sprocket or brake disc.

- I soaked the tires in a 104 degree hot tub for 5 minutes to help them stretch over the rim. They went on like butter.

- Hot soapy water really helped - would have been much harder without it. I even soaked the tube in hot soapy water for a minute to help it move into place once inside the tire without kinking/twisting. Just make sure no water gets in the open valve stem when soaking in the bucket.

- I knew the rim lock was used to keep the tire from spinning on the rim, but was not sure exactly how it worked inside the tire. Before I put the tire on, I secured the rim lock. The rim lock should go on before the tire, but don't tighten it down yet. Once the tire is on, the rim lock needs to be in place, but as loose as possible (pushed away from the inside of the rim by pushing on the rim lock bolt) so that the bead of the tire can fit between the rim and the sides of the rim lock. Once the bead is in place correctly on either side of the rim lock, blow the tire up to help seat and position the tube and tire evenly. I kept the valve stem pin out so that I could blow the tube up a few times to even everything out and seat it. Bouncing the tire also helped. Once the valve pin is back in place, blow the tire up to around 40 PSI to seat the bead. Then, tighten the rim lock down to secure it against the internal bead of the tire against the rim. Finally, let air out to set the correct PSI.

- Oh yea... pay attention to the directional arrows when mounting the tire. Not sure why or if it matters.

Hope this thread helps out the next neophyte!

Fred T · Sep 20, 2002

A few more tips:

1. I put the rim lock in after I fit one side of the tire on
2. I like to leave a littel air in the tube to keep it from twisting and keep from pinching it with a tire iron
3. I use tire spoons - they don't pinch tubes as easy
4. I apply baby powder to the tube to keep it from catching anything inside the tire and helps it seat properly. (Smells baby fresh)
5. If you don't have a hot tub use the sun or a hair dryer.
6. I toss the rim strip and use duct tape -much less PITA with rim lock
7. I use a galvanized garbage can for a tire mounting rig, just put a towel over the lip to keep from scratching the rim
8. Use soap on the rim so that it will eventually dissolve and the rim will seat the tire securely.
9. Don't use the nut on the tube stem, just leave it off incase the tube slips on the rim it won't tear a hole in the tube and give you a flat.
10. Swearing while wrenching on a tire always makes you stronger and the tire eventually pops right on!

Smit-Dog · Oct 16, 2002

Well I have around 90 miles on the new skins, so here are my impressions:

- Conditions: A variety; a little of the fine Michigan sand, but mostly medium-firm, loamy, black/brown dirt. Some slippery, slimy, hard mud, and a bunch of those U.P. Moon rocks - as big as cars and small houses, smooth, but covered in moss in some spots.

- I noticed the biggest difference with the rear tire. Big, solid hook-up. It may have been the nice grippable dirt, but I could loft my front end with just a flick of the wrist. Before it took some concentrated effort and the right terrain. I don't think any tire would have helped more on the moon rocks - it's not as much about traction as it is about momentum (and picking the right line)!

- The front end did still wash out a little at times, but dug in at just the right time to keep the bike on track. I need some more time to really get a feel for the tire's limits and overall confidence in the front end.

I'd recommend getting S12s (if appropriate for your conditions) on a new bike instead of waiting for the stockers on the KDX to wear out. The bike handles better, and seems more powerful because of the hookup.

Anybody want to buy a set of the stock Dunlops - cheap?

Hope this helps...

colem · Oct 16, 2002

Hey smit-dog,

You say your front was washing out, if you havent already, set your rear sag! Mine had a problem washing out in corners, at first I thought it was just the tire but even a brand new m-12 didn't help. Once I set the rear it stopped completely.

R. Phillips · Oct 17, 2002

Question:
I too am looking to buy new tires. My local dealer is allot higher than mail order. But I'm leary about buying sight unseen without clearly understanding the size issue.

My question is, what do the numbers really mean ? I thought the first number represented the height and second number represented width ? I must be wrong cause it seems different mfr's use different numbers for same size tires.

I'm looking for multipurpose tires for my 01' 220. My trails are woods, mud, sand, creeks(some really deep), and some hardpan.

Thanks

Smit-Dog · Oct 17, 2002

Originally posted by colem
Hey smit-dog,

You say your front was washing out, if you havent already, set your rear sag! Mine had a problem washing out in corners, at first I thought it was just the tire but even a brand new m-12 didn't help. Once I set the rear it stopped completely.

Thanks for the tip colem! I have read about setting sag, but I keep forgetting to actually do it. I will do it before riding next weekend to see if that helps.

This forum is the best... :thumb:

Smit-Dog · Oct 17, 2002

Originally posted by R. Phillips
My question is, what do the numbers really mean ? I thought the first number represented the height and second number represented width ? I must be wrong cause it seems different mfr's use different numbers for same size tires.

I'm looking for multipurpose tires for my 01' 220. My trails are woods, mud, sand, creeks(some really deep), and some hardpan.

I can't make a comment about the the S12s if your riding area in 'Bama has a lot of small rocks. But in lower Michigan we have mostly sand and loose pack. The S12s are a good choice here - especially compared to the stockers.

As far as size, I went with the 90/90-21 front (I believe that this is the only 21" size Michelin makes in the S12), and a 120/90-18 rear. See other comments here about the pros/cons of the 120 size versus the 130 and 140.

The first number is the width of the tire, and the second is the height, expressed as a percentage of the width. For some reason I think that Michelin's sizing is a little different compared to other manufactures - but I could be wrong.

Good luck!

Michelin S12 Tire Sizes?

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Fred T

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OLD-N-SLOW

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