What are the pros and cons of using a 26" tube on a 29" wheel?

[Flowrider]

I recently upgraded after 20+ years from a 26" to a 29" wheel.

Consequently, I have 8 new 26" tubes in my garage.

I ride 90% mountain biking.

Curious.

Have you ever fitted a 26" tube on a 29"?

What was the result?

And would you recommend it?

[meamoantonio]

tried 27.5 to 29 once tire bead didn't seat to the rim, so just went home instead instead and went tubeless

[Flowrider]

@meamoantonio And how have you found going tubeless?

[Zviedrs]

I'd say you can use it as a spare tube. A 26" tube will be more prone to punctures, but if it fits on the 29" rim, it can work as a temporary or emergency solution. I've never tried such a setup, though.

But would a 29" tube work on a 26" rim?

[meamoantonio]

(07-07-2025, 01:55 AM)Flowrider Wrote:  @meamoantonio And how have you found going tubeless?

If were talking about mountain bikes id say its the best decision ever, you will not look back at having inner tubes but if we're talking about road bikes it a totally different story

[ReapThaWhirlwind]

Never tried it any can't say I'd recommend it either.

Inner tube fit can flex the internal diameter, but not really the radial diameter.

As mentioned, getting it to seat is a nightmare, especially if it's too small.

I learned this when trying to put 25c tires on a 19c rim. It simply would not seat properly, and no tube magic will fix that.

However, consider this, using a tube that's slightly larger size means there's more material. Some people will say it increases pinch flats, but more material will be inherently more flexible, and thus plenty strong enough, especially if you're using higher PSI.

[Flowrider]

Thanks for the input, appreciated.

I think I'll go with @Zviedrs suggestion and use it as a last resort and install a 29" soon as. Think being much thinner on mountain bike tracks wouldn't be a good idea.

Interesting, but don't think a 29" on a 26" would work. Could it even get the pressure you want? 🤔

Don't know, but fortunately, I don't have to consider it anymore. 😁