Many wheel and tyre companies are pushing tubeless tyres and wheels at the moment. For those who don’t know, tubeless tyres are similar to a clincher, but form an air tight seal against the rim and contain sealant, instead of an inner tube.
But what happens when you puncture a tubeless road tyre? Do they actually work? To test this I took an American Classic road tubeless wheel, fitted with a Bontrager 25mm tubless tyre and sealant and pumped them to 80 psi.
Having put several hundred kilometres on these wheels and tyres without incident, I decided to force the issue to see how effective the puncture protection is. The first test I did was to roll the tyre over a line of drawing pins, or thumb tacks if you are American.
Pulling them out resulted in the holes sealing almost immediately. I should also note that puncturing the side walls with the tacks (not shown in the video) appeared to seal just as easily too.
Having seen off multiple pins with ease, I next opted for a hammer and nail. To my surprise, the large hole was sealed in around 20 seconds and would have probably been quicker if I had been riding and the wheel spinning. Although there was some loss of pressure, the tyre was still perfectly rideable and you could always top it up. I repeated this experiment several times, with the same result.
So there you have it, the tyre seals very effectively. I was so impressed with these tyres that after making this video I went on to use these exact tyres in the epic 254km Rapha Manchester to London Ride, despite the fact I had previously driven nails into them! They performed flawlessly, with no punctures and being tubeless meant I could run them at lower pressure (65-70 psi) for substantially more comfort.
If you are unfortunate enough to get a larger puncture, you can place a piece of rubber in the tyre and insert a standard inner tube. The only real downside is that fitting a tubeless tyre can be harder than a standard clincher, especially with certain rim/tyre combinations. I really like these Bontrager R3 tyres, but it was a struggle getting them onto these particular rims.