Vittoria Air-Liner tire insert

This bright green foam noodle is one of those bicycle products that doesn’t seem necessary at first. I didn’t think I needed Vittoria’s Air-Liner tire insert. Then I tried it and realized that I wanted one for every mountain bike I had.

Yes, the Air-Liner sat neglected in the garage for a couple months, coiled up like an exotic snake. After a catastrophic flat tire at the Grand Junction Off-Road, when I pinched my tubeless tire so bad that the rim cut its sidewall, I decided to give Vittoria’s tire insert a try.

The concept behind the Air-Liner (and all tire inserts) is pretty simple: By putting a piece of foam inside a tubeless tire, you protect the rim from impact, give the tire greater support at low pressures, and dampen the compression and rebound of the simple air spring that is a pneumatic tire. However, it isn’t as simple as grabbing your kid’s pool noodle and stuffing it into a tire.

Vittoria uses a special polymer foam in the Air-Liner, chosen for its density to control compression, as well as its durability. According to Vittoria, one of these inserts will last for 2,000 hours of riding.

The Air-Liner is also shaped in a specific way to improve ride quality. The overall cross-section is round, mimicking the tire casing. A channel atop the Air-Liner affords room for the tire tread to flex naturally, so it doesn’t feel like a solid rubber wheel on a Strider bike. The edges of that channel flex progressively — soft at first and then becoming more supportive under greater force. The channel on the Air-Liner’s underside leaves room for the tubeless valve and affords a bit more air volume in the tire.

Installation is more challenging than a tubeless tire without a tire liner. With some tire/rim combinations, we had to resort to tire levers to pop the last bit of bead onto the rim. Fortunately, it wasn’t too much of an ordeal, especially with wide rims that are common on most new wheels.

The Air-Liner comes in four different widths for everything from 1.9″ XC race tires to 4″ fat bike rubber. You simply cut the liner to fit your wheel diameter, up to 29″. The Air-Liners get slightly more expensive and heavier as you go up in size.

If you live somewhere with particularly rocky trails, you might consider Air-Liners front and rear. For me, only one in the back was enough to put my mind at ease.

And that extra support was immediately noticeable on the trail. Running 20psi in my tire, the traction and grip were noticeable, but it didn’t fold under heavy cornering or when the bike compressed hard at the bottom of a steep drop.

The protection from hard rim impacts was also a big improvement over simply running tubeless without an insert. In rock gardens where I would routinely hear the ping of a hard impact, things got quieter. I still felt some of the worst hits, but they were deadened. Rugged trails just felt a bit smoother overall.

Unfortunately, running a tire liner like this doesn’t mean you’re immune to flats. I had a tread puncture from a sharp rock at Breck Epic — nothing the Air-Liner could have prevented. However, the Air-Liner does make trailside repair a bit trickier. I had to use a bit of finesse to fix that hole with a tire plug because I was butting up against the Air-Liner. Also, if you had a major puncture that required a tube to limp home, it would be tough to wrestle the tire off with the Air-Liner in place.

Sure, a serious XC racer might also cringe at an additional 90 grams of rotational weight on their race bike, but cross-country courses are getting rockier and gnarlier, following the lead of the World Cup circuit. Time lost to fix a flat, or the money needed to replace a cracked carbon rim, surely outweigh that 90-gram penalty.

Those drawbacks are not enough to stop me from running an Air-Liner on the rear tire of my cross-country bike, as well as my trail bike. The ride quality, flat protection, and impact insurance have made me a believer.