Has anyone tried a 19" rear wheel? I want to run a dirt track setup with dual 19's on my '09.
Thanks

 

So you already have a 19" front ? It might fit on the rear as long as the rim/tire isn't much wider than the 18" its replacing.

 

Unless you have some supply of dirt track Dunlops/Maxxis tires on the cheap, none of which are technically street legal, I have no clue why you would want to do this. The only reasonably priced dirt track style tire available is a vintage type Duro HF308, but it's a six ply and wouldn't suit the KLX. All else are around $200 each.

I did a lot of searching for flat track type tires when doing my street tracker 500. The actual Dunlop and Maxxis tires run about $200 each new and are too wide to be an efficient tire on a 250 streetbike. There used to be the Dunlop K180s in a 19 front and 18 rear, but they're gone from the U.S. market. The actual dirt track tires available are pretty thin in availability. There are the dual sport coarse tread tires that some pass of as a flat track type tire, but they aren't.

Oddly enough, you can get a Maxxis 120/70-17 dirt track tire, the one that is acutally used on the minis that flat track. They would be the trick on a KLX for sure, especially one of the supermotos. Still technically not road legal. The KLX could pull them fairly well. There are some on ebay for $175 each in the medium compoud, no hard available.

If I wanted dirt track type tires I'd be looking at the 17s just because of the reasonable width. I'm not sure how they would wear though.