Inner Tube Size

[Dessert Storm]

Going to order a 120/90-17S TKC80 for the rear of my 650. Been swithering over which inner tube option to go for - natural/butyl rubber; heavy duty/standard etc etc. Unless I'm missing something glaringly obvious (a not infrequent occurrence), I can't find a heavy duty tube in the exact size. DirtbikeBook site suggests that 350/400 OR 400/450 tubes can be used in 120/90 tyres. So which would be best? 95% of my riding will be on-road, but I'll be doing the Stella Alpina in July, and sooner or later will be persuaded by Mudwiz to do a rally-type thing.

Opinion/experiences welcome!

[Austin]

I have never understood the concept of a heavy duty inner tube. Surely if something is going to get through a tyre, a tube no matter how heavy duty isn't going to make much difference is it? Unless I am missing something.

[Mudwiz]

Know what Austin means, never thought of it like that! Do use the biggest, heaviest tubes I can get though, 4mm rubber reinforced MX tubes, and I fill them with Slime - stuff from Halfrauds.

Size wise, 120-140 17s seem fine, spares wise carry a front, cos it will go in the back for a while.

Rallies wise - yeah!!! Fit rimlocks too, and keep it spinning!!

(Not noticed any extra vibes from all this either, although there are warnings that one might!)

[Dessert Storm]

Mudwiz -
Hmm, yes: rimlock. Suppose I'll have to fit one if I'm going to subject my TA to the sort of abuse yours gets! Did you have the wheel dynamically balanced after fitting one? Does it make tyre changes even more of a PIA?!

Austin -
Yes, I know what you mean. I think the logic is more to provide protection from the tube being nipped by the rim and from impacts from rocks etc, rather than from sharp objects that puncture the tyre casing.

[Austin]

Austin -
Yes, I know what you mean. I think the logic is more to provide protection from the tube being nipped by the rim and from impacts from rocks etc, rather than from sharp objects that puncture the tyre casing.

or from idiots wielding tyre levers . Yes, good point hadn't thought about that.