Muddymoles

How to: repair a tubeless (UST) tyre

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Posted by Matt on April 15, 2008 under 'Tips'.

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Sunday's ride saw one puncture. Me. Odd you might think given I'm running tubeless tyres but there is a simple reason for it. Originally my Orange Five came equipped with Panaracer Fire XC Pro's in their tubeless incarnation, to go on the Mavic 819 UST wheelset.

All functioned perfectly for about 400 miles until I got a rip in the front tyre that the latex couldn't seal. No problem, at the time I just put in an inner tube to get home. But somehow there it stayed, with me thinking 'I'll repair the tyre properly next time I puncture'. Except I didn't puncture again until Sunday, by which time I'd clocked up 968 miles!

So, shamed finally into working out how to repair a UST tyre, here's what I found:

1. Take out the inner tube and attempt to reinflate the tubeless tyre without it, in order to find the tear in the tyre.
2. Realise that you need a really good seal on the tyre bead, so take the tyre back off to clean the bead thoroughly of any dried latex sealant.
3. Put tyre back on and reinflate. Pump like mad with your track pump in order to get enough pressure to seat the tyre on the rim. This may take some effort.
4. Use the sharp pointy thing from the tyre repair kit to slightly enlarge the hole you have now been able to find.
5. Take tyre off and push a strip of repair patch (covered in rubber cement) through the hole using the pointy thing again.
6. Gently ease the pointy thing back out, which has the effect of cutting the repair strip in half so that the two halves are now sliced and wedged alongside each other in the hole.
7. Wait five minutes, put tyre back on and fill the tyre with about 60-80mm of latex fluid, (easiest with a syringe from the chemist). Trim off the excess repair strip too.
8. Pump the tyre back up. Pump like mad etc. in order to do this, which as mentioned may take some effort.
9. Make sure the tyre is properly seated before pumping up to about 50psi, then spin the wheel to ensure the latex is evenly coating the inside of the tyre.
10. When you are happy with the repair (like, next morning), set the tyre pressure to your normal operating pressure.

That's it. Actually the process was a lot more straight forward than it sounds and not even particularly messy. You could even complete steps 5 to 7 without removing the tyre again I guess which would 'save you some effort' and avoid some mad pumpage.

Be sure to carry that old inner tube with you on the trail though as there is zero chance of you repairing a tubeless UST tyre on the trail, simply because you'd never get the air into the tyre without a track pump. You might even find you need a tyre boot if it's a bad cut.

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