My front wheel is a 29×3″ tyre. Set up tubeless but i want to carry a spare tube for the inevitable time that i have puncture that won’t seal.

Seems to be little choice in 3″ tubes and they’re not cheap – but is an actual fat/plus 3″ tube necessary, or can i realistically get away with something smaller?

For something that’s ’emergency’ use I’d want to know it was the right thing for the job.

Having a tenner’s worth of tube in your bag for years as insurance isn’t that big a deal v a fiver’s worth that might go ‘pop’ as soon as you get it up to pressure or ride over the first root or rock?

You’ll always need it at 10 at night in January when it’s pissing down.

That is what i was leaning towards – but seen conflicting opinions and people saying how even a 2.25 is fine in a 3+ tyre – which sounds a bit of a stretch..

tbh, it probably would be fine.

I’ve used 2.5″ tubes in 4.8″ fat tyres as they’re so much lighter but for emergency use I always carry a full fat tube I know will work and keep working.

Put it this way – I’ve run a 2.5/3″ inner tube on my 4.8″ fat tyres for years, never had one go pop! Any size from 1.8″ upwards will work, you could even use a 26″ tube. People worry far too much about inner tube size 😉

When I bought my Krampus it had Surly 3″ inner tubes fitted that weighed about the same as a small star. They also seemed really prone to punctures.
I then started using much lighter Conti 29er tubes (1.8″-2.4″), and not only were they lighter, they also seemed to puncture less.
I went tubeless with it a couple of years ago, but have a Conti 29er tube that I carry just in case. Not had to use it yet!

thanks all – sounds like i should at least give ‘normal’ tubes a go first, hopefully only as backup…if i can get the chronicle to finally seat.

I can confirm that a 20″ tube won’t work in a 29″ x 2.4″ tyre. It went in (eventually), but blew up after a few yards. 🙂

Ended up packing the tyre full of bracken to get home.

Schwalbe SV19F tubes are 29×2.1 – 3.0 and are only 250g

http://nextdaytyres.co.uk/details.aspx/SV19F-29-Schwalbe-InnerTube-Presta-40mmValve/78/4857