18" HD tube in 17" wheel ok ?
 

I have an 18" 4mm thick inner tube by Michelin, they don't make a 17" in this thickness - anyone any experience on using on XTZ660 (2008 on). I am guessing that being natural rubber it should take up the extra 1/2" radial gap without worrying ?

I used an 18" tube in my KLR 650, which uses a 17" wheel, for several thousand miles with no apparent ill effects. If it were me I would rather have the thinner tube in the proper size. If you are not stuck on Michelin, there are other manufacturers that make 17" HD tubes.

use the right size tube
 

hi a word of warning, i had a over sized tube in the rear once and had a puncture caused by the tube having folds inside the tyre which i didnt know about untill i had a flat ,the folds had rubbed against each other and worn holes in a few places, so i would go for the right size tube hope this helps steve

i have had the same thing happen as well in a 18" wheel with 18" inner tube because it was to wide for the tyre being used so it caused a crease .
save your money get a standard tube in the correct size.

If you're stuck with using an over-sized innertube (I've often seen it recommended to just take a 21-inch as it'll fit an 18-inch tyre), use a lot of talcum powder (baby powder) in the tyre and around the tube.
Yet another thing to carry, but they say dry powdery dirt will work as well. Not sand though I should think.
I've never tried fitting a wrong-size inner tube, but always use talcum powder when fitting a tubed tyre.

18" tube
 

rode my klr round for 18 months with 18"tube in it with no probs but that just because i didn't no it was in there until i got a puncture.just fit the right tube and be safe