29-er puncture problem

This may seem like a silly question, but have you got rim tape on? I
left mine off on a 20" Nimbus rim and I got loads of little holes all
the way around it from the spoke holes. if you hav then try thicker
tape??

Pinch punctures in most cases are where the tyre is underinflated and
the walls of the rim puncture the tube.

I prefer a high pressure for 29ing as I can't hop up curbs at speed very
well so I kind of pummel into and over it. Makes for a smoother more
responsive ride too.

Someone is bound to be able to give a better reply!

--
one wheeled stallion - Guerilla Unicyclist

OWS

"...I explain briefly to him that such conduct leaves him vulnerable to
accusations of being an idiot. We part as enemies" - Mikefule

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Sounds like a pinch flat scenario, in which case you should raise your
tire pressure.

--
U-Turn - Member of Generation XO

Weep in the dojo... laugh on the battlefield.

'29er Tire Study' (http://u-turn.unicyclist.com/29erTireStudy/)

'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)

'New York Unicycle Club' (http://www.newyorkunicycle.com)

-- Dave Stockton
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None of the spokes are pushing up into the rim tape are they? If you've
recently tightened up the spokes, then the end of them can be poking out
through the nipple too far and push up the rim tape. You can then pinch
flat on the spoke end, which gives you a hole (or several evenly spaced
holes) either on the outside or inside of the tube close to the
middle.

When I've seen normal pinch punctures, they've usually been long holes,
often one on either side, where the rim hits the tube.

If you sidehop with a narrow rim and a fat tyre, it's easy to pinch on
one side. Have you been practising big sidehops? I found the notos
rolled sometimes if the pressure was too low and that could lead to
pinch flats.

The way to avoid pinch flats is to pump up a bit more. It's worth having
a big pump at home with a pressure guage, so you can quantify how much
you're pumping it up each time.

Joe

--
joemarshall - dumb blonde
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Cheers for the advice.

I have got rim tape, though I'm going to buy some more as it's looking
raggy.

I'm pretty sure the spokes aren't stuck up, but I'll check them at the
next puncture repair.

Concerning pressure, I don't have a guage so just do it by feel. Also
use a hand pump which limits how high I can go.

However, yesterday went to my brothers and used his foot pump/guage-
turns out that I'm on psi of around 30, when the tyre wall says 40-65.

So I put it up to 50 psi and will try it out today. If the punctures
stop them I guess it's time to buy a track pump and keep the psi high.

Can someone just confirm that the right inner tube for 29-ers is 700 x
35-45? Thats what it says on the tube box, but the tubes seem a bit
tight when I put them on.

Cheers.

--
onewheeldave - Semi Skilled Unicyclist

"He's also been known to indulge in a spot of flame juggling - but it's
the Muni that really fires him up."

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onewheeldave said:

*Can someone just confirm that the right inner tube for 29-ers is 700
x 35-45? Thats what it says on the tube box, but the tubes seem a bit
tight when I put them on.*

That is correct.

--
U-Turn - Member of Generation XO

Weep in the dojo... laugh on the battlefield.

'29er Tire Study' (http://u-turn.unicyclist.com/29erTireStudy/)

'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)

'New York Unicycle Club' (http://www.newyorkunicycle.com)

-- Dave Stockton
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onewheeldave said:

*I have got rim tape, though I'm going to buy some more as it's
looking raggy... turns out that I'm on psi of around 30, when the tyre
wall says 40-65.*

Sounds like you've found and fixed your problem.

This might seem a little obvious in hindsight, but the weight a tire
carrys on a unicycle is roughly twice what it would be on a bike. Since
most of the tires we use were designed for bike use you should stay at
the top end of the pressure range, or even overpressure it a little, if
you want to avoid pinch flats.

Then again, raggedy rim tape can be a problem too. Though at 30 PSI I
doubt you've got enough pressure to sag the rim tape enough to have a
hidden spoke puncture the tube. That's a problem that is occasionally a
problem on high pressure (over 90 PSI) tires.

Good luck

--
cyberbellum - Level 1.0 rider!

I was standing in the park wondering why frisbees get bigger as they get
closer. Then it hit me.
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Dave,
Another good trick is to line a tire with talcum powder before inserting the tube, and I always line the valve up with the tire decal to have a reference
point when checking for problems. Cheechee