Help with tube sizes - 29"

So I’m looking for a tube for my coker, I’m going to go the 29er tube approach a shot, though, I’m not sure about the size naming. I’ve been able to find up to 26" then it goes to the 700 x (xx-xx) sizes. Would a 700x40-45 work for my purposes or am I looking for something totally different?

I was thinking about doing the same thing after I popped my innertube for the first time.
Here’s a nice link.

So I guess the size I mentioned is too small? Has anyone successfully used that size or smaller? I think I may give it a shot. Ack, I don’t want to wait to order one and it doesn’t seem like I can find bike shops with one larger than what I mentioned.

This is the tube in question:

Sorry to bump this thread back up but I’m leaving tomorrow and wont have access to a bike shop for a couple days so its my last chance to get my new coker sitting back at home in working order(got it used, just needs a tube). Does anyone happen to have any input as to whether a 700x40-45 tube will work for a coker?

A 700x40 is a touring bike tube.

The people who’ve done it so far have used 29" mountain bike tubes which are more like 700x60.

It might just work, but probably won’t. I’ve had one of those touring tubes explode inside the 700c Big Apple tyre, because the rubber was stretched too far inside it. You’d quite likely go through a few tubes trying to fit it whatever, people seem to have all manner of hassles fitting normal 29er tubes to cokers, let alone an undersized one.

Personally I’d just get an order off for a coker tube now, rather than messing around and spending money and time on multiple 29er tubes.


Ah okay, thanks for the heads up, I won’t waste my money then. It’s a shame, I was looking forward to being able to ride this weekend. :frowning:

Don’t get the 700x40, it’s too small. If you’re trying to save weight, the 29" tube that’s generally recommended for this is the Schwalbe AV19. It’s rated for tires up to 28x2.35. I’ve had good luck with it in the 36er. Go to and order a proper 36" tube even if you go the 29er route. You’ll want a backup.

After hearing how much trouble people have had with this, I wanted to say I just joined the 29er tube conversion club, with virtually no hassle!

I’m not great at getting tricky tyres on - I’d never managed to get my 36" Radial tyre on to any rim (stock or airfoil) myself before (almost reduced to tears of frustration before going to a bike shop once!).

But I got a “29” tube (the Schwalbe 28" x 2.35" - needed stretching enough, wouldn’t have liked anything smaller ) and had a go …

An hour later and I had a successful 29er tube inserted on my 36" airfoil (not an undersized ‘X’ one). First time :smiley:

I used two normal tyre levers - not very stiff or strong, probably came free in a puncture kit once - and some washing up liquid (must be the magic ingredient) to lubricate the partially inflated tube and inside of the tyre bead. Also some string - I tied the tyre down into the rim to keep the bead inside on the opposite side as it was slipping back out as I worked around. Cable-ties/zip-ties would’ve been ideal.

And a quick hill ride this morning… wow! It’s true what people say who love this - a real difference. Feels suddenly more gazzelle-like and less tank-like.

Not so scary to do really (or maybe just lucky!)