MTB rims, tyres and inner tube sizes

[desertraven]

Hello All,

I have a MTB which previously had a set of 26”x1.95” tyres, I changed them to 26”x2.4” tyres the other day.
The new inner tubes are rated as 26”x 1.75” to 2.5”.
The rim is marked as 26x20 (I'm not sure what the 20 means).

Anyway from what I’ve read my new tyres should fit my rim’s without any problems, and they do, but I’ve gone through two inner tubes in as many days (one on each rim).

Is it just a dodgy batch of inner tubes or are the tyres too big, i.e., 26x20 mean nothing bigger than 2.0”?

Thanks

 

[lpretro1]

These inner tube are fine for your wheel/tyre. If you are having problesm then likely in the fitting process - prob nipped the tube as you are fitting it.

 

[desertraven]

Thanks lpretro1

I bought some better quality inner tubes also used talcum powder to spread around the tube and inside the tyre to help reduce the chances of things sticking to each other - so far so good.

 

[Smurfy]

The rim is marked as 26x20 (I'm not sure what the 20 means).

That's probably the measurement of rim width where the tyre beads sit.

 

[Cyphrex]

What if I was to go opposite of lpretro1? I bought the bike from a friend with 26 x 2.125 tubes and put semi slick Specialized Hemisphere Armadillo tires 26 x 1.95 over the tubes. I'm not sure what the bottom rating for the tubes are but they had 26 x 2.1 MTB tires on them. I will only be riding on streets for exercise and maybe next year do some bicycle rides on public roadways (12mi-20mi) and don't want to damage my new toy. I know the hot Texas weather here could cause some issues for blowout but the tires are rated 35-65 PSI but I'm only running 50 PSI with a solid tire.

 

[Rickshaw Phil]

What if I was to go opposite of lpretro1? I bought the bike from a friend with 26 x 2.125 tubes and put semi slick Specialized Hemisphere Armadillo tires 26 x 1.95 over the tubes. I'm not sure what the bottom rating for the tubes are but they had 26 x 2.1 MTB tires on them. I will only be riding on streets for exercise and maybe next year do some bicycle rides on public roadways (12mi-20mi) and don't want to damage my new toy. I know the hot Texas weather here could cause some issues for blowout but the tires are rated 35-65 PSI but I'm only running 50 PSI with a solid tire.

Hi and @Cyphrex

The size difference is fairly small so to be honest I'd expect those tubes to work fine in the narrower tyres. Tubes usually fit a range of sizes so you have some flexibilty. The worst that is likely to happen with a large tube in too small a tyre is that the tube might crease when fitted and at some point in the future might puncture at the crease.

It's good practice to take a spare tube and some basic tools to fix a puncture with you on rides so just make sure your spare is the right size and enjoy your rides.