http://www.wiggle.co.uk/geax-pack-of-5-mtb-ultralite-inner-tubes/

I have ‘Dirt Dan tyres’ and ordered the 1.10-1.50 inner tubes. I took out the old one and it seemed much wider. (I presume this is to do with the figures?)

Anyway I thought sod it I’ll try, low and behold the tyre went down after 100m. Question is what do the figures mean and are they mentioned on the tyre and does it matter? I looked but couldn’t find any)

Apologies lots of naivety here.

Thanks in advance.

How big are your tyres? Tubes do stretch, not often you’ll have a problem. Saying that, they are quite small tubes you’ve ordered. Wiggle are pretty good with returns though.

1.10-1.50 refers to the width of the tube (the diameter cross-section) in inches, so if you’re running modern, run-of-the-mill mountain bike tyres you’ll most likely want something around about the 2″ mark to be on the safe side. You can run skinny tubes but they’re more likely to puncture as the rubber is stretched thinner to fill the tyres.

did you put the tyre on with tyre levers?

The inner tube ought to stretch. If you put the tyre on with levers, there’s a fairly good chance you inched the tube and casued a flat.

In my weight weenie obssesed, xc racer days, I used to use 1.25″ tubes as the would stretch but not weigh as much. Had a tendancy to puncture unless pumped up hard though, so not really very good!

I’ve just done a quick google and it appears the Dirt Dan is a 2.5″ tyre.

So you need 2.5″ tubes (you’ll probably get away with 2.25″ tubes) Also, the ultralite tubes you bought will be useless against punctures.

Thanks, not sure what size tyres are just standard schwable ones?

Didn’t use tyres leavers.

I understand now and it makes sense. I could get away with skinnier tyres but it isn’t ideal. Back to wiggle it is then.

Thanks again guys. Perfect.

Should say what size the tyre is, on the sidewall. It’ll be along the lines of ’26×2.5′

How come they are useless against punctures?

I think it’s because they are stretched further, therfore damage more easily. That’s what I think anyway. They certainly were more puncture prone.
Oh, and te ride was odd as well. They seemed to deform more for a given pressure.

Thanks again.