Well it finally happened; I’ve had my first puncture in the rear tubeless set up since first installed in back in May and it’s fair to say that I have learnt a few valuable lessons as a result.
To start with before I felt the rear tyre going soft I heard the very slight hissing sound on the wet roads as I was riding home in the rain on Saturday.
Mistake number one, I continued to ride assuming that it would seal itself, but it didn’t so I was then forced to stop and investigate further. The problem was actually a cut roughly about a couple of mm in length rather than a thorn type puncture. So with the wheel rotated so that the cut was at the lowest point I inflated the tyre and sure enough it sealed ok.
Mistake number two, instead of giving it a few minutes to fully "cure" I was off again and no surprises but within a couple of miles it was clear that it was still losing pressure. So repeated the same again, this time allowing more time! Rode home and the tyre was still inflated after an hour, so happy days.
However, considering that it was a cut, rather than a thorn related puncture, was I really 100% happy to rely on some liquid latex sealing the cut and more importantly holding fast while say descending at 40+mph? Of course the answer is no, I wasn’t happy.
So we now move into unknown terrority, removing a tyre to add a patch to reinforce the carcass while it’s still containing 2oz of sealant.
Popped one side of the tyre off and was quite shocked to see that no liquid Latex sealant was remaining at all in the tyre? Instead what greeted me was continuous fawn coloured bead of sealant about 20mm wide and a couple of mm thick stuck fast around the whole inside circumference of the tyre and a lightly covered coating on both of the inner sidewalls either side of it. There was a small amount of sealant remaining, maybe a couple of tea spoonfuls if that? I do however accept that when the cut first occurred the sealant would have started to escape but when I stopped it wasn’t exactly gushing out, just a rather feeble drop every now and then, so certainly not a significant lose at all.
Fully removed the tyre and dropped it in a sink of hot water and washing up liquid and set about cleaning the solidified sealant off. In truth it wasn’t too bad to remove, and armed with an old scrubbing brush and the tyre folded inside out, after 1/4hr all done and back to “as new”.
With the tyre fully dried, I squeezed the cut open from the inside and dropped a tiny drop of superglue in the cut and then pinched it shut to fully seal the cut. Then as a belt and bracers repair, I then added a Park self adhesive patch, job done.
Before refitting the tyre, I decided to remove the No Tubes valve that is screwed into the rim as there was a certain amount of congealed sealant around it. Now this is where I could see a problem out on the road if you encountered a catastrophic failure in the tubeless tyre and you were forced to fit a tube. Your first obstacle would be removing said valve unless you just happened have access to a pair of pliers?
With the valve suitably cleaned and replaced, one side of the tyre was refitted…….now comes the faff! You have to fit an inner tube and then fully install the tyre and then inflate to maximum pressure or until you hear the tyre popping on to the wheel beads either side of the rim. To be honest its best to utilize a compressor to get that sudden high volume of air in order to get both the beads to seat. NOTE - I have never had any joy doing this without the use of tyre soap. With the both beads “popped” into place, now deflate the tyre and remove one side of the tyre again, remove the inner tube and inflate the tyre again.
Now deflate the tyre yet again and remove the valve core, using a Stan No Tubes syringe screwed onto the valve, inject in the 2ozs of sealant. Some people add the sealant direct into the tyre when the one side of the tyre is removed, but personally I find this to be messy if the beads don’t seal and you have to remove to add more tyre soap.
Mistake number three, the amount of sealant in the tyre needs to be checked on a regular basis and it was clear that after three months during the summer months and in the regions of 4500 miles, most of it has solidified rendering the puncture resistance pretty much useless! So a note has been put in my diary to check it again in a couple of months time and it’s a simple enough process, just remove a small section of one side the tyre and peep inside and see what still remains in liquid form.
Failing that, just add a could of ounces of sealant every two months and after a year you will be sure to never get a puncture again as you would effectively have a solid tyre!!!
So all in all, its fair to say that I’m not 100% convinced with tubeless tyres at the moment due to the amount of faffing about with 1) the initial installation. 2) in the event of a cut tyre and the need to repair. That said, it got me home and if it was dark and raining then it would have been a blessing. So I think that I will see the life of the tyres out first or if I get another puncture and see whether or not I scrap the idea and revert back to inner tubes again?
To be fair, even if it was a tubed tyre combination, I would still have taken the tyre off to repair the cut so the extra hassle is the sealant and getting the tyre to reseat on the beads. And its also very clear that in order to afford yourself the best possible puncture resistance you need to be checking the contents of the tyre at least evry couple of months, in the summer months at least.
The odd thing is, I have been running tubeless tyres on my MTB for at least the last eight years and not suffered any problem with the sealant solidifying at all and encountered many minor punctures all of which have sealed near enough straight away without the need to stop and inflate. But I suspect that it down to the difference in working pressures between road and MTB tyres?
EDIT - It is worth noting that Stans No Tubes do recommend checking/replacing the sealant every 2 to 6 months dependant on the climate.
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