Dropped off my KLX 250S last week to a local shop I've done business with over the years and told them I wanted the Michelin T63 tires on the bike as I had them on my XT 250 and really liked them.

Picked up the bike today and the tires looked really small on the bike, after closer inspection they put on an 80/90/21 on the front and a 110/80/18 on the back.

Using a tire size chart they are definitely much smaller than stock..........

Question, I'm going to have them put a 130/80/18 on the back, will I have any issues? Michelin does not make a 120/90/18.

Also, probably riding 75/25 on the street and when I do go off road it's mainly gravel or good dirt roads, nothing hard core.

Or, will the smaller tires be just fine performance wise but just look a little small on the bike?

Thanks,

RLJ

 

Responses will probably not be objective on this because even with equally size stamped tires, there often seems to be just a bit of comparison variance. I run a Kenda 760 rear in the 110/100-18. Due to the relatively low power of the KLX, a big, meaty rear tire like a 130 may look cool but isn't always the best choice. It may work out just fine. Are you using stock gearing? That's a noticeably taller tire and may affect gearing. If you still have the stock chainguard, it might make contact, but a lot of us don't run the chainguard anyway. Remember that even a Yamaha WR450R only uses a 120 tire.

 

Thanks for the input. Michelin does make a 120/80/18, I might look at that size. Just can't get over the look of the 110/80/18.

 

If the OP puts a 130 on the 250 the only "advantage" is the fat tire look. The tire is far too wide, making for too much weight, too much friction, and likely too much grip for the small lower powered 250. The 650 has 39 hp based on some publications' dyno runs. I can tell you I certainly wouldn't put a wider tire on my 650. If actually going off road I'd probably drop to a 120. Honda actually uses a 4.60 on their XR650L. Take that for what it's worth when considering such a fat tire for the KLX. Is it for look or for performance.

I actually went narrower than the 110. I went to a 4.10-18. Knowing what it was like running a 125 back in the day, the trick to preserve power and to be able to break the rear wheel loose when I want to was to stay narrower. We ran 3.50-18 on the 125 mx bikes, where the guys going for the look ran 4.50 and 5.10 wide. The narrower tire is lighter, taking less power to rotate them.

I knew I'd be in some sand and mud, making a narrower tire work better when it gets buried in the stuff. Still has adequate traction because the narrower carcass can spread a bit on rim getting a bit more tread on the ground versus the wider tires which actually will pinch up for a narrowed foot print. It did fine in the 8-10" deep sand in Michigan, unfortunately I didn't...

I'm riding a dual sport with some off roading in mind, not a cruiser or supermoto. Function comes before form, but I like the form too. It gives the bike a lighter more MX look to the back half. I like that.

Last good part, in my case the Duro 4.10 was a decent chunk less costly than the 120, actually about $30 less than the 130 I use on the back of the 650.

Try the 110 or even a 4.10 they can do the job. They're function over form. Ask a guy that spends the kind of time I wish I could riding off road - TNC. I'd take my lead from him.

 

I'm looking at the T63s myself. I planned to use the 120/80 on the rear. For the front, I have no clue what to go with. I'm thinking 90/90???

 

90/90 is pretty normal. Some offer an 80. With the sizing issues among manufacturers you need to look up the real size on their sites.

In another tire size post I did some research and found some interesting stuff. It is totally true that sizing varies over manufacturers. A 120 in some brands can be up to 1/2" difference from others. I found one that was 4.78" and another that was 4.37" I also found a 4.60 may vary from around 4.5" to 4". Not much consistency. If a rider wants to know what they really are buying they NEED to go to manufacturers' sites and see what the specs are.

The same tread style from two different manufacturers, Kenda 270, IRC GP1, and Shinko 244, may be totally different. The Kenda has both a 4.60 and 120, the former is 4.3" wide and the latter is 4.8" - 1/2" difference. (In the brand I use, Duro, they have both the 120 and 4.60 listed at the same width, 4.8".) IRC has their width metric at 105mm, which converts to about 4.13". The Shinko only lists inch sizes and the 4.60 is 4.37". Makes you wonder what the sizing deal is in the industry, it sure can be screwy. Especially when a 4.60 is THREE different sizes over 3/4" range.

So, advice - do what I do, probably a number of others have done. Pick the kind of tire you want, then go to the manufacturer's web site and see what they have as an actual measured width.


In an interesting side note to add to the confusion, Kawasaki's listings show a 100/100-18 on the back, but in tests it appears a 4.60-18 Dunlop 605, measurement claimed at 120mm is used. So, apparently a tire about 120mm or 4.78" wide is used, in spite of the 100/100 listed by Kawasaki... go figure!

 

After much research, definitely go with the 90/90 in the front and 120/80 in the rear. Much closer to stock sizes.

I ended up ordering the Dunlop 606's. Taking the small 80/90 and 110/80 T63's off tomorrow. I like the way the T63's rode on the street however they looked to small for my taste. Still going to keep them as they only have less than 10 miles on them........

 

Thanks for the sizing tips. Now for the next issue! What the heck tube sizes do I choose? I can't find a 120/80-18 or a 90/90-21 from the vendor I'm using. I'm trying to stay with the same ebay store because they're one of the very few who will ship out to Guam. These are MSR Heavy Duty tubes.

Rear Tire: 120/80-18
Tube options:
100/100 110/100 120/100

Front Tire: 90/90-21
It looks like the only tube option is 80/100.

What to choose?

 

They are all so close it would make no difference. 10mm is about 3/8". Most tubes cover a couple tire sizes, so I'd run the 80/90-21 and the 110/100-18

 

rear tire is 120x.8=96... the 100/100 or 110/100 should be good.
front tire is 90x.9=81... the 80/100 would be 80x1=80... good to go!