120/80-18 fits on the rim beautifully and makes a nice round tire profile.

 

The 110 & 120 are the width. The 80 is the the ratio of the height to the width. So the 110/80 is 88 high, the 120/80 is 96 high (approx). To add to the confusion is how stretchy a tape measure the manufacturer uses and whether they measure the casing width or the overall width (more of an issue with a KNOBBY knobby). If you have any stores nearby that sell a selection of tires, go in and do some measuring. In the case of the Kenda K261 I think wildcard's probably right, now that I've done the arithmatic. With our bikes you want to avoid getting a tire any taller than stock as that "raises" the gearing.

 

The OD on the 110 is 25.10 and the 120 OD is 25.49. The 120 weighs about a half pound more. I'm going to go with the 120 because it is the same width as the stock tire and the extra OD (taller gearing) is okay for mainly street use.

Here's what I'm going with:
Amazon.com: Kenda K761 Dual Sport Rear Tire - 120/80-18/--: Motorcycle Superstore
Amazon.com: Kenda K761 Dual Sport Front Tire - 90/90-21/--: Motorcycle Superstore

Unless someone sees a big problem. From the videos I've seen online it seems as though with a little work I can swap them myself. For a few days last week I was considering selling the KLX and getting a street bike. But then I looked at her in the garage and though "I can't sell you!" My 2007 is bone stock so I'm probably finally going to get around to some of the more basic mods this winter. Pipe, snorkel and jetting.

Thanks again for all the help.

- Mark

 

Are there tubes in these stock tires?

 

Not in mine

but normally yes.

Actually mine do have a very small tube in them, but no tube out where the tread is...

 

I don't get it? What's the point of having a tube if it isn't touching (supporting) the actual tire?

 

Look up TuBliss. It's a system that some of us really like. It's not DOT rated, if that makes any difference to you.

To the OP...if you've never changed a motorcycle tire before, you need to look for some video's to study. If you are working hard, you aren't doing it right. The main thing is the get the OPPOSITE side beads way down in the rim groove next to the spoke heads...if you don't do this, it's very, very frustrating. With a little practice, and a little lube, it's not hard at all.