MTB inner tube max PSIs?

mart123

Hi guys,

I'm using my MTB currently to get to and from work along a canal path. It's basically cinder track most of the way; far from road-like, but not exactly full off road style riding either. I bought Kenda Kommuter tyres as a compromise, and I've really quite liked them... easier going than full on MTB tyres, but still give me more grip on the cinder track / mud than slicks would.

The tyres have a max rating of 85psi. I realise that's way higher that anyone would normally dream of inflating MTB tires for trail use, but I was tempted over the last few days to inflate them somewhere close to that max to see how I go. Felt much better on the even stretches in terms of rolling resistance, but it should probably not have surprised me when I split my inner tubes on the way to work this morning.

Looking around I don't see any pressure ratings on inner tubes, I guess because they tend to be held together by the tyres (hence the normal "go by what the tyre says" notice?). Am I just using poor quality tubes, or should I be looking for a specific type of tube for those kinds of pressures??

Thanks in advance,
Martin.

Wooliferkins

I've looked at a few brands on the shelf and no PSI rating on the tubes. Old tube? Too small for the tyre?

nicklouse

no rating on tubes.

look at road tubes. they are thinner than MTB but the tyres need more pressure.

mart123

No, brand new tube. Only fitted one of them last night straight from the box!

The tyres size is 26 x 2.02, and I'm using tubes which say 26 x 1.7-2.1. The 2 which split this morning actually shipped with the tyres, so I was pretty sure they should be OK....

http://www.amazon.co.uk/gp/product/B001 ... X2MX3RTAWY

Chunkers1980

Dodgy batch perhaps.

How's your rim strip/tape?

rockmonkeysc

The pressure is taken by the tyre/rim not the tube. The tube just acts as an air tight bladder. If the tyre will take the pressure your ok.

mart123

Rim strip seamed fine; the rims are virtually new anyway.

Maybe I just got a dodgy batch then. I've ordered 2 from a different brand so I'll give those a bash and see how I get on.

Thanks for the advice guys.

The Rookie

I use Schwalbe tubes on my commuter, fairly light (at 120g ea they match some latex ones) I use the 1.0 to 1.25" inside the 1.5" (slick) tyre and have had no problems at all at 80psi, they have over 600miles on them at that. Not to expensive either, I got them for £3.45 ea.

Simon

mart123

The Beginner wrote:

...the 1.5" (slick) tyre ...

Simon, do you run those on MTB rims??... I wasn't sure if I could run something that thin. I was looking at these, primarily for the puncture protection, but also reduced rolling resistance...

http://www.chainreactioncycles.com/Mode ... elID=24629

Chunkers1980

You can - some people run 1", but I find 1.5" gives a bit more flexibility

The Rookie

I'm running 1.5" slicks on a 17mm (front) and 19mm (rear) rim without problems.

http://www.sheldonbrown.com/tire_sizing.html#decimal scroll down to the red/green table near the bottom, remember this is rim INTERNAL width!

Simon

mart123

Superb, thanks guys.

Came here looking for advice on inner tubes and it ended up being new tires AND tubes!

mart123

Just been doing some reading about tyre width vs rolling resistance etc, and I'm suddenly much less convinced that a change in tyres is going to be a good thing. I've read a lot about thinner tyres not necessarily => lower rolling resistance, but then most of the opinion / research seems to be for already pretty tiny road tyres.

I'm currently running Kenda Kommuters - 26 x 2.1. Max 85 PSI.
I'm thinking of switching to Schwalbe City Jets - 25 x 1.5. Max 65 PSI.

Any opinions on whether it's worth the switch?? I'm happy to spend the money if it makes my ride slightly easier, but I don't want to throw it down the drain!

Chunkers1980

Don't fixate too much on PSIs - I run mine lower in the winter to get more deformation in the corners as very hard tyres don't like quick switch turns in the damp.