Vittoria announces run-flat foam tire inserts for road bikes

Ride on a flat for up to 50 km and add security to tubeless road tires for just 22 g per wheel.

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Remember those mysterious tire inserts that the EF-Education First team was supposedly using at the Tour de France last September? After several months of additional testing, Vittoria has finally lifted the lid on the new road-specific version of its Air-Liner foam tire inserts.

The new Air-Liners are essentially a downsized version of the foam inserts that Vittoria already offers for mountain and gravel bikes, albeit with a somewhat different mission statement and a different shape to suit. Many foam inserts designed for the dirt (whether from Vittoria or one of the other multiple brands who now have such a thing) have a somewhat triangular or trapezoidal cross-section so as to maintain casing stability when running extra-low pressures. In this way, riders can enjoy improved cornering traction and better ride comfort without worrying about the tire squirming around or denting (or cracking) a rim due to impact. 

When there’s no pressure inside the tire, the foam material can fully expand to mostly fill the inside of the tire casing. Photo: Vittoria.

These new road-specific Air-Liners, however, are primarily there to provide security if your tubeless tire goes flat and can’t be repaired with a plug or sealant. The polygonal cross-section is effectively round, and its overall diameter is somewhat undersized so as to sit more snugly in between the tire beads. The closed-cell foam doesn’t absorb sealant, and it’s also quite light. An insert for 25 mm-wide tires is claimed to weigh just 24 g, and my sample is actually slightly lighter at 22 g. There are two bigger sizes, too: Vittoria says the one for 28 mm tires is 31 g, while the one for 30 mm-wide tires is 39 g.

According to Vittoria, rolling resistance isn’t affected at all when the tire is inflated. While the foam insert fills up most of the tire volume at ambient atmospheric pressure, pumping up the tire also puts pressure on the foam insert, squishing it down against the tire bed so that it essentially never touches the ground when the wheel is rolling down the road. 

If you lose that pressure, however, Vittoria says the foam once again expands to fill most of the tire volume, not only allowing you to limp home up to 50 km (31 miles) at up to 20 km/h (12 mph) without too much risk of damaging your wheel, but also acting as a sort of mild beadlock to keep the tire from peeling off the rim.

This is how Vittoria says the Air-Liner insert reacts to internal pressure. It seems to actually work like this in reality. Animation: Vittoria.

Retail price is US$40 / £35 / €35 per liner (including the requisite tubeless valve stem), while a complete kit with two liners, an installation tool kit (more on this in a bit), and enough sealant for two wheels is US$100 / £90 / €80 (Australian prices are to be confirmed).

Speaking of sealant, Vittoria has a new Universal Tubeless Tire Sealant formula designed to work well for both low- and high-pressure applications. It’s ammonia-free so it shouldn’t eat aluminum rims or nipples, and its low viscosity supposedly works better on smaller pores than thicker stuff so as to minimize weeping, while a bunch of suspended “platelets” are said to help plug cuts up to 7 mm-long. 

Vittoria is offering it in multiple sizes, starting at a conveniently portable 8 ml up to a more shop-friendly 1 L bottle. Retail prices range from US$7-25 (pricing for other regions is to be determined).

First impressions

I haven’t had a chance to ride Vittoria’s new road-specific Air-Liners just yet, but I certainly have some feedback on the installation process. If you think standard tubeless clinchers are already enough of a pain that you’re heading back to #teamtubeinside, just stop reading now. But if you’re already familiar with Vittoria’s other inserts — or, even better, something particularly arduous like CushCore — these aren’t too awful.

That said, the tool kit is highly recommended. Because the Air-Liner’s smaller diameter fits quite tightly on the rim bed, you can’t press the tire beads into the rim’s center channel as easily as usual — and even if your thumbs can manage the task, the foam serves to push the bead out toward the sidewalls, just as it’s designed to do. 

The installation tool is sort of like a fancy set of pliers, providing the necessary leverage to squeeze the tire beads toward each other so that you can insert a series of temporary spacers. These keep that tire bead in that center channel of the rim so that you have enough slack to make it all the way around. It sounds like a massive pain on paper, and if you regularly struggle with tires as is, it’ll certainly seem that way in real life. But if you’ve already got pretty decent technique, it actually isn’t all that bad, and I was able to get a full set installed in less than fifteen minutes. 

These spacers are designed to keep the tire bead in the center channel of the rim for easier installation. Otherwise, the foam insert continually pushes the beads out toward the sidewall.

From there — and again, because that foam insert serves to push the tire beads outward toward the edges of the rim bed — getting the tire inflated and seated is a cinch, even with a standard floor pump. 

When the tire is inflated, Vittoria’s claims that the insert doesn’t influence rolling resistance seems to hold true. As promised, when the tire is flat, you can feel the insert providing some support to the tire, and if you put your weight on it, you don’t feel that hard edge of the rim like you normally would. And then even at a modest pressure of about 50 psi, you can press your thumb into the tire a surprising amount before you feel the firmness of the now-compressed foam.

I’ll find out soon enough if the Air-Liner works as advertised while on a ride, but initial impressions are promising.

That said, there’s one major caveat here. Vittoria’s Air-Liner better work as it’s supposed to, because you unfortunately have no recourse if it doesn’t. It may not be unreasonably difficult to get the things installed, but there’s absolutely no way you’re yanking them out roadside to install an inner tube if the sealant isn’t sealing and/or you can’t get the hole plugged. And even if you could, where would you put the thing? It’s much too big to stick in a jersey pocket, and it’d be covered in nasty tubeless goop, anyway. 

The Vittoria tire pliers provide plenty of leverage to grab the tire and yank it to one side. In fairness to Vittoria, I see myself using this tool for a lot more than just installing tire inserts; it’ll be great for stubborn tires in general. But unless you’re planning on carrying these with you, don’t count on being able to remove a tire roadside to install a tube.

According to the team mechanics, EF is using Vittoria’s new foam inserts as more of a temporary measure in races, allowing them to enjoy the rolling resistance benefits that good tubeless setups offer over traditional tubulars, while still letting riders safely continue on a flat long enough to get a spare wheel. EF apparently hasn’t been the only Vittoria-sponsored team using them, either. According to Vittoria, Alexander Kristoff (UAE-Emirates) was using them when he won Gent-Wevelgem in 2019. Either way, as far as the pros are concerned, ease of repair when running these things is something for the mechanics to worry about later.

On the one hand, this sort of run-flat capability sounds like it really could be great in a race situation or if your rides don’t tend to go all that far away from home. But just like run-flats on a car have their limitations, the ones on Vittoria’s new road-specific Air-Liners might be enough to keep them from being more widely appealing, too. 

Stay tuned for a review in the coming weeks.

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