Vittoria Tires has rolled out a version of its Air-Liner tire inserts for road bikes. This new insert is designed specifically for tubeless road tires and will allow cyclists to ride with a partially- or fully-deflated tire up to 31 miles / 50 kilometers at reduced speeds.

These inserts have already been tested in the pro peloton during the 2020 Tour de France by the EF-Education First team and racked up a victory under Alex Kristoff at the Gent-Vewelgem in 2019. Tubeless is steadily chipping away at tubular hegemony in the pro ranks and is becoming increasingly popular with recreational cyclists, but does Vittoria's Air-Liner Road offer real-world benefits beyond the ranks of professionals? I tested this run-flat system to failure to find out.

What is a tubeless tire insert?
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Let's start with a quick primer on the types of tire inserts on the market. Tubeless is the norm for mountain and gravel bikes. Tubeless inserts are commonly used for aggressive mountain biking and enduro racing.

In addition to this new Air-Liner, Vittoria makes tire inserts for mountain and gravel bikes. The primary purpose of tire inserts for mountain and gravel applications is to create a buffer zone between the tire and rim. This prevents the tire from impacting the rim when the rider encounters a sharp or square-edged obstacle, likewise tire inserts also shield the rim from dents and cracks. Secondary benefits of these tire inserts include increased traction from the ability to run lower tire pressures, a reduction in high-frequency vibration, and less tire squirm at lower pressures, as the insert bolsters the inner wall of the tire.

The objective of tire inserts for the road is different. The primary purpose of these systems is to keep the bead firmly in place in the event of a puncture and to allow the rider to ride safely on a partially deflated tire.

How does Vittoria's Air-Liner Road system work?
Vittoria's Air-Liner Road inserts are constructed from closed-cell foam that doesn't absorb tubeless sealant. The foam cells compress as the tires are inflated to riding pressures, shrinking the insert and allowing the tubeless sealant to flow freely through the interior of the tire. If the tubeless sealant is the back-up plan, the tire insert is the back-up to the back-up plan.

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When the tire is punctured, the sealant (hopefully) seals the puncture, but if it doesn't and the air pressure continues to drop, the tire insert expands, filling the void and allowing the rider to pedal home. Vittoria claims these run-flat inserts are good for approximately 31 miles/50 kilometers at reduced speeds.

What's in each kit?
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Vittoria's complete Air-Liner Road kit retails for $99.99 and is available in Small, Medium, and Large versions to fit most road tire and rim widths. The kit includes Vittoria's Multiway tubeless valves, two tire inserts, Vittoria's new tubeless sealant, and tire installation tools. Tire inserts can be purchased individually for $39.99 per liner. The Road Tubeless Tool Kit can be purchased for $24.99.

SIZETIRE WIDTHINTERNAL RIM WIDTHWEIGHT
Small25mm21mm24g (each)
Medium28mm23mm31g (each)
Large30mm26mm39g (each)

Does it actually work?
I tested the smallest version of the Air-Liner Road with Vittoria's 700x25 Corsa Control tires on a Bontrager wheelset. If you've had a hard time fitting tubeless tires on road wheels, then Vittoria's installation process may present a new layer of headaches. If you're accustomed to installing mountain bike tire inserts, you're probably already prepared to come equipped not only with the proper tools but with a bit of patience and elbow grease.


Vittoria's Road Tubeless Tool is well thought out and gets the job done. Results will vary based on width, and tire/rim combination, but I managed to install the insert and tire with standard tire levers. Removing the tire and insert did require the use of Vittoria's tire pliers.
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After installation, I rode the bike around the neighborhood with the tires completely flat. Steering is compromised compared to riding with fully-inflated tires, but I was able to safely ride and corner at 8-10mph without damaging the rims or risking unseating the tire bead. It felt like I had 20-30psi in my tires. The sensation is best described as "squishy but manageable."

I then inflated both tires to my riding pressure of 70psi and hit the road. As mentioned, when fully inflated, the tire inserts shrink. I couldn't tell they were present and didn't seem to detract from ride quality. According to Vittoria, the inserts have no affect on rolling resistance.

I used my trusty Feedback Sports Dual-Sided Pick to puncture the front tire. Air hissed, sealant spewed, and within a few rotations of the wheel, the leak was sealed. When I checked my tire pressure after the ride, the front tire was holding steady at 48psi. The first line of defense had successfully done its job and it seemed like the pressure was low enough that the insert had at least partially expanded within the tire. This is probably the best-case scenario for these tire inserts—stop the leak and reinforce the tire sidewalls to provide more support and better performance at lower pressures than you would otherwise have without it. The worst-case scenario would be if you experience a flat and your destination is much further than the suggested 31 mile/50-kilometer run-flat range. Without tubeless inserts, you could insert a spare tube and continue on, but from my experience, this would be very hard to do with these inserts installed.

Which brings us to the real question, who is this technology best suited for?

Who benefits?
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Vittoria's Air-Liner Road inserts work as advertised, but the real question is "Cui bono?"

First and foremost, these tire inserts can give a competitive advantage to racers that outweighs the scant weight penalty. Rather than waiting along the roadside for support, an athlete can continue on—albeit at a slower speed—and minimize their losses as they wait for a wheel swap. I think we'll see widespread use of these and similar inserts in the Spring Classics and possibly even time trials. Triathletes, both professional and amateur, are another group who are likely to wholeheartedly embrace these tire inserts as a secondary line of defense against flat tires.

There's also the safety aspect to consider. A flat during a high-speed descent can easily lead to a crash. As the Air-Liner expands, it locks the bead in place, preventing the tire from unseating and, hopefully, allowing the rider to safely come to a stop. Tire inserts can be a good means to get home safely on a flat tire for riders who are not very mechanically inclined. (Though I'm not sure how many of these riders would run tubeless tires to begin with.) When looking at the broader state of the road cycling market, these tire inserts are also a stop-gap technology for the lack of coherent fitment between road tubeless rims and tires—some road tubeless tires and rims work well together, yet other combinations are very hard to install and remove.

Verdict
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Vittoria's tire sealant and Air-Liner inserts provide a great first and second line of defense against flat tires. The sealant is quick and effective and, when all else fails, the Air-Liners will get you home. This is an option worth considering if you're looking for an additional insurance policy against flat tires.