[This article was last updated on November 9, 2017]
Your car has tubeless tyres. Mountain bikes have by-and-large moved over to tubeless tyres in the last decade. And now it’s available for road bikes. Well it has been available for some time, though it’s been slow to catch on; but there’s ever-increasing choice now and a growing number of cyclists are making the leap. Is it time you did too?
But what are the advantages to ditching the inner tubes? Just what are the pros and cons?
What is tubeless?
Tubeless is basically a clincher tyre inflated onto a rim with no inner tube. Instead of an inner tube holding the air pressure, an airtight chamber is created with a tubeless-specific tyre, developed with a special (commonly carbon) bead, and a compatible rim. The tyre bead locks into the rim and forms an airtight seal that maintains the pressure.
Road tubeless was first brought to market by Hutchinson and Shimano in 2006 (though Mavic and Michelin had a stab earlier in 2004) but it’s fair to say it wasn’t immediately a runaway success.
Why is that? For starters, most professional riders don’t use tubeless, which for a lot of cyclists is enough reason not to use it. Tubular tyres are still dominant in the professional peloton because it’s a weight obsessed sport, and tubulars still offer the lightest setup. It’s also because a tubular stays on the rim during a rapid loss of air. Fitting a tubular tyre is a lot of hassle though, and much more tricky than fitting a tubeless tyre.
Clincher tyres with inner tubes are still popular because they're simple and work well. Most people can easily change an inner tube and punctures can (if you’re lucky) be quite rare. There’s also no issue with compatibility. Any tyre will fit to any rim, and the market is awash with a staggering choice of both.
Mavic enters the fray
The biggest news in tubeless tyres is the recent arrival in the sector of French wheel giant Mavic, which announced its Road UST (Universal System Tubeless) wheel/tyre system in June 2017.
Mavic says Road UST is easier to use and safer than previous tubeless systems and has put its production facilities where its mouth is, with a range of 15 wheels.
The difference between Mavic’s system and others is that there’s tight control over production variances, Mavic says. Variation in tyre bead stiffness and size affects safety as well as ease of installation and removal. Keeping the tolerances small is crucial to the success of the system.
Mavic says that Road UST is going through the approval process to become a standard recognised by both ISO (International Organization for Standardization) and ETRTO (European Tyre and Rim Technical Organisation) working groups.
What are the advantages of tubeless?
Why go tubeless at all then? The main advantage, and it’s a big one, is the substantially reduced risk of puncturing. There is no inner tube to puncture, whether from sharp objects penetrating the tyre or, more rarely, pinch flats when the inner tube is squashed between the rim and tyre.
To get the best out of tubeless, and to provide the extra puncture resistance in the absence of the inner tube, there is one extra ingredient that is needed: liquid sealant. This sloshes around inside the tyre and then reacts with air when the tyre casing is punctured, and plugs the hole. It can seal most small holes caused by flint or thorns and while you might suffer a small drop in pressure, you can continue riding.
They’re faster. Because there aren't two layers of material (tyre and tube) pressing against each other and the tyre can deform more easily, the rolling resistance is often claimed to be lower. If German tyre company Schwalbe's claims are to be believed, its latest One Pro tubeless tyre is the fastest tyre it has ever manufactured. It could be just saying this to sell tyres of course, but it still produces top-end clincher and tubular tyres, so it’s not like it has abandoned traditional tyre technology just yet.
Moreover, with no inner tube and therefore no risk of pinch punctures, a tubeless tyre can be run at a lower pressure. This provides increased comfort as there is more cushioning from the tyre. Tubeless tyres, in our experience, provide exceptional comfort with a compliant and supple ride that surpasses most clincher tyre and inner tube combinations.
However, while this ability to run lower pressures is appealing to mountain bikers, who appreciate the increased grip and elimination of pinch flats, traditional road cyclists are unlikely to be interested in dropping pressure in narrow tyres. If your track pump only knows 120 psi, then the advantages of tubeless might be lost on you.
In our experience, a tubeless tyre is best run 10-20 psi lower than an equivalent clincher tyre with no degradation in performance. As the trend moves towards wider tyres though, being able to safely run reduced pressures makes a lot more sense. The prevalence of endurance bikes with 28mm and wider tyres, and gravel and adventure bikes with even wider tyres, make a strong argument for tubeless.
Are there any downsides?
Unfortunately, there are a few downsides to converting to road tubeless. You don't have quite as wide a choice of wheels and tyres, but that has improved dramatically in the last couple of years. Many wheel manufacturers now offer tubeless compatible wheelsets, with some providing dual compatibility with regular clincher tyres, providing an ideal upgrade path. If you’ve bought a new bike recently, it might very well have tubeless-ready rims.
While wheel choice has improved, tyre choice is still a bit restricted and is really the big hurdle to converting to tubeless. The tyre company showing the most interest, and commitment, is German company Schwalbe. I’ve been really impressed with their recent tyres, and there’s very little weight penalty or difference in ride quality. Other choices include Vittoria, Bontrager, but so far big players such as Continental and Michelin have shown little interest in offering tubeless tyres.
Most critically, installing a tubeless tyre isn’t quite as straightforward as popping an inner tube in. That’s not helped by a lack of a single unified standard that all tyre and rim manufacturers adhere to, leading to some compatibility issues between certain combinations of rim and tyre. As well as a tubeless tyre, you need a compatible rim which might involve fitting a special rim strip, a tubeless valve (and it needs to be long enough and threaded so you can get the pump on it) and a bottle of sealant.
If you’re upgrading it’s quite a costly exercise. If your bike has tubeless wheels when you’re in luck as you just need the tyres, valves and sealant. Some manufacturers are starting to sell bikes with tubeless-ready tyres and even supply the valves, so making the tubeless conversion is much less costly. The benefits however might outweigh the initial outlay - and you’ll save money on inner tubes.
A tubeless tyre isn’t invincible. The sealant can deal with most smaller holes but anything big, like a slash or cut, will require you to fit an inner tube, so you still need to carry a spare or two. To be fair to tubeless, any cut of a reasonable size would also cause a puncture in a tubed setup.
Converting to tubeless: a brief guide
If you like the sound of tubeless, what do you need?
You need tubeless compatible rims. There is now a lot of choice (Shimano, Campagnolo, American Classic, Stan’s etc) and they either come with a rim bed that doesn’t have any spoke holes, or a rim strip ready fitted. With some tubeless ready wheels you need to remove the basic rim tape and install a special rim strip. This makes the rim airtight.
Then you need a tubeless tyre. Schwalbe is arguably leading the way at the moment, with the One Pro race tyre but also wider options for the emerging gravel market. Vittoria, Bontrager, and Hutchinson also offer tubeless ready tyres.
While it is possible to bodge a tubeless set-up with a regular clincher tyre and non-tubeless rim, it really isn’t recommended and could be potentially dangerous. Tubeless tyres are designed to ensure the tyre bead locks securely into the rim so it can't dislodge at high pressure, which is something you definitely don’t want to happen. This is the critical element of a successful tubeless setup and is why some companies haven’t developed a tyre yet. You might get away with regular rims but you definitely need proper tubeless tyres.
A regular tyre uses an aramid bead, and without an inner tube, can blow off the rim at high pressure. Tubeless tyres use a non-stretch carbon fibre bead — this was the big breakthrough by Hutchinson — that prevents the tyre blowing off the rim.
Tubeless valves. These are standalone valves with a rubber bung on one end that butts up against the inside of the rim, and a locking nut that tightens the valve onto the rim. There are many different makes of tubeless valve, our recommendation is to get one that is compatible with your rim. Look for a removable core - this can make inflating and adding sealant easier, and a lots of thread to screw a track pump onto. The valve needs to be long enough for the depth of your rim.
And don’t forget a bottle of sealant. There is plenty of choice on the market and it’s more or less the same stuff. The sealant should remain liquid in the tyre for up to six months, provided you have no punctures that allow it to escape during that time. Some sealants are 100% free of ammonium so is environmentally harmless.
Bontrager offers an upgrade kit (it’s pricey though) that includes everything you need to convert to tubeless, bar the wheels. It includes tyres, rim strips, valves and sealant.
Another option is the Slime Pro Tubeless Ready Kit, which provides a bottle of sealant, a roll of rim tape, tubeless valve, tyres levers and a CO2 canister for inflating the tyres. It aims to allow you to use a regular non-tubeless rim but you must use a proper tubeless tyre.
Should you convert to tubeless?
Tubeless still has a little way to go before it is as universal as it is in the mountain bike world. For tubeless to really take over from conventional clincher tyres, the installation process needs to be much easier, as at the moment it requires an investment of time and expertise. It’s also costly, especially if you need to factor in the cost of new wheels and tyres.
Tubeless also needs commitment from other tyre and wheel manufacturers to widen the choice, and there needs to be a common standard to provide the compatibility to eliminate the current installation woes that can create a sour first experience of road tubeless. One thing is for sure, people that have converted to tubeless have become fans, as once you experience it, it’s very hard to go back.
There are clear benefits to tubeless (reduced flats, lower pressures, ride quality and they’re faster) but it won’t save you any weight. However, if you’re prepared to invest the time, and money, in converting to tubeless, you probably won’t look back. It won’t be for everyone, but tubeless is here to stay and its future looks bright if our experience is anything to go by.
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.