Fairy visits at higher pressure

[Stig-OT-Dump]

I keep getting rear wheel punctures on the tandem.
Normally happens after I've pumped up to between 45psi - 60psi and around 5 miles into a cycle.
I replace the inner tube, pump up with a compact hand pump to a lower pressure than before and then all is OK. Till I get home, use the track pump and then 5 miles into a ride....
There is nothing sticking through teh tyre. I take it I need to look at replacing my rim tape, or should I be looking at the rims?
Cheers for any advice
Stig

 

[wisdom]

Longshot,but could the guage on the track pump be faulty? That way you could be exceeding the pressure. Just a thought.

 

[MrJamie]

I think it was on Sheldon Browns site where it's explained that the higher the pressure of the tyre and the weight on the tyre, the higher the pressure applied to the road, from both a smaller contact area on a firmer tyre (think high heels) and less ability to bend/absorb things, so its more likely to push sharp things through.

Just to be sure though, check if the holes in the tube are on the inside or outside of the tube (valve side or tyre side), which should help indicate if its things through the tyre or rim tape. Also are you putting the little nut on the valve? Sometimes if that's on too far and you pump the tube up too much itll tear where the valve joins the tube. Take it off while you inflate with the track pump, or throw it altogether

 

[srw]

What size are the tyres? At only 45-60psi on the tandem they must be monsters - I've run 1.5" tyres up to 100psi without a problem.

When you inspect the burst tube, where's the damage? Can you match the damage to a point on the tyre or rim?

 

[byegad]

What size are the tyres? At only 45-60psi on the tandem they must be monsters - I've run 1.5" tyres up to 100psi without a problem.

When you inspect the burst tube, where's the damage? Can you match the damage to a point on the tyre or rim?

+1 My first thought was that the pressure is way too low.

 

[PhunkyPhil]

I had a wheel which kept puncturing and I examined the tyre multiple times, the problem was the rim tape in my instance.

 

[actonblue]

Check the wheel and the tyre for any sharp objects. Is the rim tape correctly positioned?
Is the puncture in the same position or is the tube bursting?

 

[Stig-OT-Dump]

I'm not at home so this is from memory
The tyres are 26 x 1.7-ish, presta valves and I use the same track pump on other bikes no bother
The rim tape is more rubber than tape and can slide pretty easily
No debris or nicks in tyres, insides felt carefully every time and no apparent cause
I'm c. 200lbs and pilot. Little stig is a lightweight but it has happened fully loaded with panniers & tent, but also without anything but the wee man on the back.
Punctures are a couple of mm long and appear to be side/ inside of tube, a bit lie a 1-fanged snake bite but I'm sure I've taken good care to avoid nipping the tube when replacing it.

Thanks for all the replies BTW
Stig

 

[srw]

My best guess is that there's something embedded in the tyre which protudes by a miniscule amount - not enough to cause a problem until the tyre is pumped up adequately. I think I've had something similar in the past - though not on the tandem.

On the tandem, I tend to pump up tyres to 10psi or so above the manufacturer's recommendation. apart from anything else, it means they last a bit longer.

 

[Broadside]

Punctures are a couple of mm long and appear to be side/ inside of tube, a bit lie a 1-fanged snake bite but I'm sure I've taken good care to avoid nipping the tube when replacing it.

A friend kept getting punctures like this, one every 2 miles or less and the damage to the tube was exactly as you describe.

Have a look at this thread which shows a picture of the subtle damage to the tyre which was the culprit - it was not at all obvious to find: http://www.cyclechat.net/index.php?threads/Inner-tubes-keep-going-pop.127650/

He had to replace the tyre to resolve the problem.

 

[srw]

For a tandem in particular it's worth buying an expensive tyre. We had something cheap from Decathlon for a while, which punctured several times and lasted about 500 miles before losing all its tread. Marathon pluses (and a Durano plus and a Marathon on the fast tandem*) last for ages - although still about half the lifespan of the same tyre on a solo bike.

*the other Durano plus was destroyed by an exploding inner tube. Fortunately I spotted the bulge at the top of the twisty 30mph descent and was able to borrow a tyre to get us down the hill.