Go to the manufacturer's site and see if they have an actual size chart. Bridgestone and Dunlop do, as do others, like IRC and I think Duro too.

 

D606 is a good rear tire, some don't like the front, I do.
I've run them studded at first, but liked them so much in the snow with studs, that I tried them for the dirt. It's now my tire of choice.
They last if you can moderate the throttle on pavement, I'm not so good at that...otherwise good bang for the buck.
BTW, Ive tried K244's, K705's(love 'em for road trips), K270's and the D606.
They don't drag the motor any that I notice, plenty of room in the swingarm.

 

Thats great! thanks

 

Here is an example of the sizing charts from a manufacturer. In this case it is Duro, since I am switching to them from the Kenda K761s on the bike right now. (anyone want a good deal on some virtually new 90/90-21 and 120/80-18 Kendas?)


I used the information to decide what tire to go with. I am trying a small tire on the back, going with the 4.10-18. It is about 1" narrower and a bit lower profile than the 120/80 version. It is lighter, but has about 3/32 less tread depth. Thing is it is about 1/3 the cost of the 120/80, so I am figuring it might not be that bad a deal.

I want to see how the bike pulls with a smaller lighter tire and how it works off road too. On the old 125s the trick was to run a narrower 3.50 knobby versus the more common 4.00, because it allowed the bike to break it loose easier and spin up to stay in the power better. It also didn't eat up as much power to spin it either. So I'm trying it.

I am also going to a tire I have over 30,000 miles running on my 650. The tires on it last about 4000 miles and work extremely good both on road and off. A good tread design that works well. The pair is going to run around $100 for a known quantity.

If there was an 80/100-21 or a 3.00-21 I would consider it too. The 90/90 is 3.50" wide.

Regardless, this is how I pick tires, knowing about sizing. From there it becomes a bit more gut feeling unless someone I know has run them. In this case I took a gut shot on the Duros when I couldn't afford better back in 2001 during a layoff. I'd looked at them, but went to Avons before, but this time the Avons were too expensive. These looked good and turned out to be a great choice. I've not gone to anything else because these did everything I wanted. Now to see if the smaller size does it on the 250.

 

You`ll have to let us know how those Duros do...the 333 looks like a Shinko 244 and the Kenda K270....

Thanks for that tire size chart.

 

As I've said, I have over 30,000 miles running the Median HF903/904 on my KLX650. I ride hard on the road when we go goof around, chasing or leading friends on bikes like a DRz400SM, Aprilia SVX550, and XR650R supermoto'd. I also have done a heck of a lot of dirt/gravel roads and some single track riding with them. They really work in all the above. The cornering on pavement is phenomenal for any tire, much less that tread pattern. According to a buddy following me on a trail they clean out well (aka slinging the mud out of the tread) and I've not really had any traction problems in our riding. I know knobbies will do better in full on off road though.

I won't kid you, I am critical of tires. The Duro HF918 street tire sucked. It didn't inspire much confidence at all. I am running IRCs on the street bike now, better, but not as good as the Bridgestone BT45.

I found the Duro Median HF903/904 easily as good as the OEM Dunlop back when, and in comparison to the older Avon Gripster, on par on the street and far superior in dirt/gravel. They were so good and at such a good price that I've never bothered trying anything else.

Now I'm going to use them on the 250. The real experiment is with the smaller size rear tire to try to get better performance with less rotating weight and better off road performance avoiding bogging down with too wide a tire. I don't care about that "fat tire" look, I care about performance. They don't run fat tires on motocrossers and never have. It is about being able to get adequate grip while still being able to break the tire loose when wanted, to keep in the power. We do this on dirt/gravel a bit, grip up a loose hill and break loose when we want to slide a bit. The 650 has no problem breaking the 130/80 loose when I want to in dirt.

So the Duro is far from an unknown quantity for me.

Here are a couple more sources...

Bridgestone
Dunlop
IRC
Shinko

With a bit of digging you can find the true tire sizes and rim recommendations in most cases. Bridgestone's site is great. Look up the tire model, click the information link at the lower right and you get the full rundown on sidewall sizes, true sizes, weight, rim range recommendations and all.

 

out of curiosity, Has anyone ever run a 130/90 18 on the back of a klx? 06 in general. I found the tire I want, but I'm not sure if it'll fit or not. I assume it likely will.

 

Wreckster,
I have an 09 250s. I have a 3" rear rim and I use a 130-90 D606. I have over 32,000 on the bike and the 130-90 fits fine.

 

KLX678 that's great info. Appreciated.

Ian

 

Just a warning in advance:

If you install a 130/90, be prepared for a decrease in performance. That tire is too big for optimum performance on a 250. All it is good for is to have a fat looking tire. Fine for profiling, but lousy for performance, be it acceleration or off roading. The tire is significantly heavier and the extra rotating weight out at that radius will eat up more power to run it. The extra width is a disadvantage when run off road will bog down the smaller engine, when it really needs to spin easier. The only way they work well is if the bike is geared extremely low. If it wasn't true you wouldn't see riders on 450 MXs running smaller tires than the 130 and 250 riders running a smaller tire than the 450s.

If the reason is to gain top speed, do it with gearing. Get a smaller rear and biggest front sprockets you can get. Fact is I believe you can get a custom tooth count and probably get as small as maybe 35 T.

There ya go, you've been given the pros and cons. Here's the summary.

Pro:

• Big fat tire look.
• Profiling image.
• It fits the rim.
• Taller tire may add some top speed if the engine can pull it.

Con:

• Heavier tire.
• Increased rotating mass takes more horsepower to run.
• Increased width a disadvantage in dirt where a small engine needs to break a tire loose when needed.
• Higher cost for less performance.

On a personal note, with past experience and what has been learned being in and around a motorcycle shop and motocrossers/track day riders, I am actually going the other way, downsizing to a 4.10-18 which is about an inch narrower, but about the same height as the OEM tire. It is an experiment to see how it pulls when off road and to see how the wear is.