I can hear it now – “I thought you didn’t get punctures with tubeless!”. Unfortunately this is not true. You get a whole lot fewer punctures and those that you do get are usually not disabling; so you can often complete your ride. But occasionally you get some bigger gashes, cuts and damage. And of course you can indeed patch them.
Take for example my ride recent ride to Hunstanton. We were riding along, not that far into the ride when I heard the tell tale ‘ppppsssss’ of air and knew that I’d sprung a leak in my rear tyre. In fact it was so loud that before I’d even had a chance to say anything a shout came up from behind me of ‘puncture!’ and the group came to a stop. By which point the sealant had done it’s job and the ‘pssss’ sound had stopped and everyone looked around saying ‘so, who’s got the puncture then?’.
On that occasion I just topped up with some more air from my mini pump. This was fine and I completed my ride, all 160 miles. However, it was a big cut and when I got back home and tried to pump up to the full pressure, the plug of latex sealant wouldn’t hold the extra pressure. So that’s how I come to be patching a tubeless tyre. While I had the tyre off the wheel and the patches out I also decided to patch a few other gashes that I’d accumulated over the year too.
First job obviously is to remove the tyre. I prefer to take it off completely, empty out any remaining sealant and then turn the entire tyre inside out. This makes it easier to handle and to see what you’re doing. Then I locate the areas that I want to patch and clean away all the dried up sealant. There’s no need to clean the entire tyre but it’s also fine if that’s what you want to do.
Then following advice from Stans I spray the area with disc brake cleaner, I use this product from Juice Lubes that I have for the disc brakes on my mtb. This evaporates away so there’s no need to wipe at all just spray and leave for a few seconds. As it evaporates it takes away excess moisture with it leaving the surface drier.
If you have a hairdryer or a heatgun like I do then heating the area for a minute now will help with adhesion of the patch as the heat will soften the rubber. Then apply the vulcanising solution that came in your patch kit and allow this to dry, ideally use your hairdryer or heatgun again for a few seconds. Then remove the foil from your patch and apply it to your tyre. You don’t need to remove the clear plastic coating on the top of the patch, I do though because I like to be neat, so I go back to the trusty heatgun and give it a blast to shrink the plastic first and then peel very carefully. If in doubt just leave the plastic in place.
Then all that remains is to refit the tyre, add a little sealant and re-inflate to pressure. If you struggle to refit and more importantly re-inflate tubeless road tyres then you will want to pay special attention to how the bead of the tyre sits either side of the valve. In my experience when I’ve got this bit correct the tyre goes up with no problem at all, but then equally there have been times when I haven’t got this right and the tyre leaks out as much air as I care to put in! It’s about getting the edge of the tyre bead on the inside of the tyre down beside the block of sealing rubber on the valve; if it is sitting on top of the rubber block then the tyre won’t seal no matter how hard you pump! Also I guess different valves behave differently, so for reference I have these ones that came with the Campagnolo 2-way fit wheels.