For years there have been just two standout wheel-tyre options for road cyclists: clincher and tubular. The former is the standard on the vast majority of road bikes for everyday use, including club rides, sportives and amateur racing, and the latter is largely favoured by the pros and track cyclists.
The benefits of either are clear. With clinchers, tyres are easy to fit and fixing a puncture is as easy as changing or repairing the inner tube. Professional riders, keen amateur racers and track cyclists love a weight-saving tubular setup which sees the tyre glued directly on to the rim.
However, both have their downsides. Clincher setups weigh more than their tubular counterparts, while the glued-on nature of tubulars means replacing the tyre after a puncture is a relatively long and drawn-out procedure. In fact, it’s only because neutral service vehicles and team cars are nearly ever-present at pro races ready to replace a wheel at a moments notice in the event of a flat, that tubulars are almost universally popular at the top level.
But, what about the third option: tubeless? In recent years, tubeless technology has steadily gathered momentum in the cycling industry, with more road cyclists beginning to make the switch - but what is tubeless, and should you take the plunge?
George Scott/Factory Media
What is tubeless?
As the name implies, a tubeless system requires no inner tube. In a very similar design to the way motor vehicle tyres function, the tyre, which has an open cross-section like a clincher, and the rim are made in such a way that fitting them together provides an airtight seal.
As a result, 'tubeless' is best described as a complete wheel-tyre system, rather than a wheelset or tyre individually.
"Tubeless wheels are relatively easy to spot," says Tom Marchment of Hunt Bike Wheels, a British-based firm which specialises in tubeless wheelsets.
"A shoulder in the inner rim creates a much more pronounced recess that the tyre bead can fit securely into, as opposed to the traditional U-shaped rim bed usually found on clincher wheels."
Tubeless technology relies upon that shoulder to allow the tyre to ‘seat’ much more securely than it would with a traditional clincher setup.
A tubeless-ready wheel often won't have any spoke holes in the rim bed, which can help improve the reliability of the rim, according to Marchment, and, along with tubeless-specific valves, provides an airtight seal. A tubeless-compatible wheelset with spoke holes will require rim tape or a rim strip to run a tubeless tyre.
A tubeless-compatible wheel works in tandem with a tubeless tyre specially treated to create a perfect seal capable of withstanding pressures - typically - of up to 110-120psi on a road bike.
"Tubeless tyres feature a tougher bead [that makes use of butyl] to provide an immediate sealing with the rim and a perfect fit," says Dave Taylor of tyre manufacturer Schwalbe.
"Due to the necessary high inflation pressure for a road bike, it is impossible to convert clincher tyres to tubeless tyres safely, simply because a normal tyre bead will not withstand the outward forces of high air pressure and the tyre will almost certainly come off. Be sure to only use tyres which are designed for tubeless fitting."
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What are the benefits?
Put simply, proponents of tubeless technology say a tubeless setup provides advantages in several key areas important to road cyclists: speed, comfort, grip and puncture protection.
The absence of an inner tube is key to a faster setup, according to Marchment.
“In the case of clinchers with an inner tube in place, there’s a level of friction between the tube and the tyre that it’s pushing against," says Marchment. "Removing that tube takes away this friction, reducing overall rolling resistance."
To reinforce that point, Schwalbe say the One Tubeless is their fastest tyre.
A tubeless setup also rules out pinch flats by virtue of there being no inner tube to potentially pinch against the rib, meaning a tubeless tyre can also be ran at a lower pressure than an equivalent clincher.
“Tubeless tyres can be used with a lower inflation pressure without compromising performance"
“Tubeless tyres can be used with a lower inflation pressure without compromising performance," says Taylor. “That brings clear advantages in comfort as well as more control.
“At the same time, tubeless systems provide high puncture protection, the danger of blowouts is reduced, and a sudden loss of air pressure by burst tubes or valve tear off is completely excluded."
A true tubeless setup also sees the tyre filled with a liquid sealant at setup - this serves to plug small cuts in the tyre - from thorns or glass, for example - before significant pressure is lost.
"Liquid sealants are used inside the tyre that serve to re-seal punctures within milliseconds," says Taylor.
In the event that you do puncture out on the road, a tubeless wheel and tyre can be used with a standard inner tube and Schwalbe always recommend carrying one just in case.
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So why hasn't tubeless already caught on in a big way?
Tubeless tyres aren’t new – mountain bikers have been using them for years and tubeless has quickly become the off-road standard, while the technology has been used in motor vehicles for decades.
However, like most technological innovations introduced to road cycling, adoption can take a long time to become universal.
“We’ve seen no real concerted push from the industry," says Marchment. “After all, clinchers and tubular technology has served road cycling well for years, so there hasn’t been much in the way of a demand. You also have to think about the learning curve involved with adopting a new approach.
"Manufacturers need to invest the time into developing the technology," he adds, "but probably won’t do this until a desire to invest time into learning the system is expressed by the rider. That leads to a comparative shortfall in the availability of the year-round tyres a great proportion of road cyclists use."
As with many technological changes, successful demonstration at the highest level is key to influencing the market. For example, despite the stuttering start to road disc brake technology, pro use has brought the technology firmly into the public eye. Tubeless technology hasn’t yet had its day in the sun in the pro peloton, despite some use by IAM Cycling, notably by Martin Elmiger who rode to fifth at the 2015 Paris-Roubaix on a tubeless setup.
That said, the tide is slowly beginning to turn. Tyre choice remains relatively limited, though Bontrager, Hutchison, Panaracer and Schwalbe are among the manufacturers to now offer a range of tubeless options. There's plenty of choice when it comes to wheels, though, from affordable training wheels to high-end carbon hoops. In fact, if you've bought a bike in the past couples of years then there's a good chance it may have come with tubeless-compatible wheels.
However, the whole industry is not on board.
Are there any weaknesses in tubeless technology?
Not all brands think tubeless is the way to go. Continental, one of the pre-eminent tyre manufacturers in the world, openly admit their scepticism towards the technology, claiming that the advantages for road use are limited, at best.
As Continental’s product manager, Ben Blaurock, puts it: “With mountain biking, cyclo-cross and gravel riding, people ride their tubeless tyres with low pressure to increase the grip level on rough terrain; low pressure creates a wider footprint and therefore a bigger contact area.
“You get more traction and are limiting the risk of pinch flats compared to using clinchers, where low pressure and a strong impact on the tyre can cause them. [In our view] these advantages don’t exist on a paved road."
Blaurock claims that until Continental find a significant performance advantage in adopting tubeless technology, they’ll stick to making clincher and tubular tyres.
While you’ll find no inner tube in a tubeless setup, Blaurock says the extra material required in tubeless tyres and rims can increase the overall system weight, so some tyre manufacturers are looking to save weight elsewhere and compromising performance as a result.
"In our opinion, the advantage of limiting pinch flats don’t exist on a paved road"
"Some tubeless tyres for the road market drop the puncture protection layer or reduce the tread thickness, which results in a higher possibility of a flat tyre as well as lower mileage," he says.
And, in the case of carbon rims, Continental claim a tubeless sealant can be limited in effectiveness due to heat build-up.
"Temperatures of more than 150 degrees centigrade are possible [under braking load], which can cause the sealant to ‘cook’," says Blaurock. "Therefore, holes which have already been sealed can become leaky again."
On top of this, there is the more obvious downside to running a system that depends on tight seals and high pressures: difficulty of fitting. This is because the seal needs to be tight before pressure is exerted on the tyre, and this can make both installing and removing the tyre a more arduous task than it would be using a standard clincher setup - though this very much depends on the wheel and tyre combination. It can sometimes require an air compressor or CO2 inflator, rather than a conventional track pump, in order to get the tyre bead to fully seat.
What do I need to convert to tubeless?
How do you convert to tubeless? You need a tubeless-ready wheelset for starters. It's vital, according to Taylor, to use a tubeless-compatible rim and not try to convert a standard clincher rim.
"You should only use wheels which are expressly approved by the manufacturer for a tubeless conversion," he says. "This is particularly important in the case of the high-pressure system of a road bike, because this will ensure that the rim will bear the specific loads tubeless use puts on it, and that the tyre fits safely on the rim with an airtight seal."
However, the term ‘tubeless-ready’ on wheels may not actually mean 'immediately ready to accept tubeless tyres.' Before fitting a tubeless tyre, the rim needs to be airtight and this may mean covering the spoke holes by fitting tubeless rim tape of the correct width or a plastic rim strip.
"Only use a tubeless setup on wheels which are expressly approved by the manufacturer for a tubeless conversion"
Hope Tech, for example, sell a conversion kit for ‘tubeless-ready’ wheels that features rim tape, a valve for each of the rims and the sealant, while Bontrager sell rim strips to cover the spoke holes in their TLR tubeless-ready wheels.
As a result, if you already own a ‘tubeless-ready’ wheelset, you may simply need to buy only the valves, tubeless-specific tyres, and sealant, along with rim tape/strips if the rim needs to be made airtight.
But should you be worried about crossing brands? Marchment says he’s never encountered a problem. "You should get a good seal regardless of the brand you use," he says. "I’ve never had a compatibility issue with this, but it’s always recommended that certain tyres work on certain rims because they’ve been tested together."
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Should you make the switch to tubeless?
There’s no doubt tubeless technology is developing, and becoming more and more visible in bike shops around the country. As with all developing technologies, improvements are still to be made - both at the cutting edge of performance, and for the everyday road cyclist.
For riders wanting to trial tubeless and the purported speed, comfort, grip and puncture protection benefits, it’s a relatively simple and affordable conversion to make, provided you already own a set of tubeless-ready wheels. At the very top end of the market, supporters claim tubeless tyres to be faster than the fastest clincher set up, while proponents of the clincher still believe their fastest tyres (and, as it stands, there's significantly more choice) are a match for the best of tubeless.
The reduced risk of punctures is a definite plus point in favour of tubeless tyres, although this can be offset if a complete failure occurs, due to the added difficulty of removing and installing such a tyre from the rim in order to fit a ‘get you home’ tube.
Should you go tubeless? If you're interested in the benefits then the best way to find out is to give it a try.