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Talking point: Is it time to bin inner tubes?

Stu Bowers
19 Sep 2018

With rumours that tyre giant Continental is to finally launch a tubeless tyre offering, could the inner tube's days be numbered?

What is tubeless?

Tubeless tyres do not need an inner tube to hold air. Instead the tyre carcass is airtight and when installed on a tubeless-specific rim, the special tyre bead forms an airtight seal with the rim hook.

Air is pumped in through a Presta valve, the base of which forms an airtight seal around the valve hole. 

Why is it beneficial not to have an inner tube?

There are several benefits, the biggest of which is reduced rolling resistance, as an inner tube generates friction inside a tyre carcass. Having multiple layers reduces suppleness, which has adverse effects on road feel and grip.

An inner tube also adds weight at a particularly detrimental point – the outer circumference of a rotating mass.

‘Comparing a 25mm clincher and butyl tube to the same width tubeless tyre with sealant, we can see a reduction of 20% in rolling resistance and a 13% improvement in grip,’ says Axel Bult, product manager at Vredestein tyres.

Removing the tube from the equation means tyres can be run at lower pressures without risking pinch-flats (when the tyre gets squashed against the rim edge under a big impact).

It is now accepted that lower-pressure tyres roll faster on less than smooth surfaces while also offering greater comfort and increased grip in corners.

‘Our data shows our tubeless tyre, ridden at 80psi, has less rolling resistance than a clincher with an inner tube at 130psi. Imagine how much more comfort that provides,’ says Bult.

What about punctures?

Another advantage of tubeless is the use of sealant, which stays mainly liquid inside the tyre, but which solidifies when it is squeezed through a puncture, blocking the hole, a bit like blood clotting in a cut.

‘Tyres used to be about managing conflicting targets,’ says Specialized’s product manager for tyres and tubes, Oliver Kiesel.

‘Performance is about reducing rolling resistance and weight, but competing with that are puncture resistance and durability. These two sides are completely against each other in a normal clincher, but with tubeless the big difference is being able to add sealant.

‘You can build light, high-performance tyres with significantly lower rolling resistance, and puncture resistance is taken care of by the sealant inside that instantly repairs small cuts and holes.’

That sounds great. Are there any downsides?

Critics will point to the difficulties of fitting tyres that by necessity must be incredibly tight to the wheel rim, and problems with seating the tyre without the aid of an air compressor.

Early adopters will have tales of being stuck at the roadside, hands and kit covered in sticky sealant, but tubeless tyre technology has improved dramatically in the nearly 12 years since Shimano and Hutchinson collaborated on the first road tubeless wheel and tyre system.

‘To achieve consumer acceptance the key was to reach a standard everyone can achieve themselves, at home or at the roadside,’ says Kiesel.

‘At the core must remain safety, so tolerances must be carefully managed while maintaining easy fitting, inflation and also ease of adding sealant. But thanks to new materials these criteria can now be met.’

Will we all be riding tubeless soon?

‘It’s about educating riders,’ says Stephen Robinson, brand manager for Maxxis bicycle tyres. ‘Tyre pressures are so critical to enjoying being on your road bike and with tubeless tyres the pressures can come right down to as low as 60-65psi, without a noticeable detriment in terms of rolling resistance. It’s incredible what a difference that makes to comfort and grip.

‘It will eventually be the norm. Just as two years ago we were still debating whether or not 25mm tyres were the way to go, now it’s all 25mm, and maybe even 28mm. Perceptions are changing, and tubeless is the next step.’

John Heasman, product manager at Vittoria, is also unequivocal: ‘Tubeless means tyres with fewer compromises. You don’t have to search hard to find mechanics who will show you their scars from trying to fit road tubeless tyres in the past, but we’ve moved on from that now.

‘Our goal was to make tubeless as easy to fit as a normal clincher, and we’re there now.’ 

Should I throw away my inner tubes?

It speaks volumes that the world’s biggest bicycle tyre manufacturer, Continental, is rumoured to finally be launching a tubeless road tyre, despite having eschewed them thus far.

Sometimes it takes a while for brands and consumers to accept new technologies – just look at disc brakes – but when the advantages outweigh the negatives, it’s only a matter of time before tubeless becomes the standard.

That said, it’s still prudent to carry a spare inner tube in a jersey pocket – just for emergencies.

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