Mountain bike tire liners appear to be moving from fringe to mainstream with the debut of the Vittoria Air Liner at Sea Otter this year. Like other foam tire inserts on the market, the idea behind the Air Liner is that it essentially adds suspension damping to the rebound normally associated with mountain bike tires, along with run-flat protection.
Vittoria adds a couple unique design twists to the idea of a mountain bike tire liner. First, the Air Liner sports a round cross section with two channels cut out, one on the top and another one the bottom. Here’s how Vittoria explains the dual-channel design.
The top channel provides room for the tunable air chamber that sits directly beneath the tire tread. Upon impact, the corner edges of the channel flex first, and progressively build to the thicker portion, as the tire is compressed. This allows the tread to remain flexible, which increases traction, without sacrificing impact resistance.
The bottom channel allows for easy fine-tuning of the air chamber, and allows for full compatibility of all valve core styles.
This brings us to the second unique design twist: the Air Liner is cuttable to fit various wheel diameters from 26″ up to 29″. To install, measure, cut, and use the included zip ties to attach the ends together. Vittoria says the bottom channel is designed to work with every tubeless valve on the market.
Air Liner effectively works as a run-flat system for mountain bike tires, as pro riders on the enduro circuit have already proven. Even without air pressure, pro enduro racers Adam Morse and Jason Memmelaar say they’ve finished rides on deflated tires that would have otherwise stopped the ride.
The Air Liner material is completely waterproof and works best with a tire sealant that doesn’t contain ammonia like Stan’s or Slime. Over time, the foam will break down, though Vittoria says it should remain effective for at least 2,000 hours of riding. Designed to work with tires from any manufacturer, not just Vittoria tires, the Air Liner comes in four sizes based on tire width. Pricing is set at $85 per wheel which makes it slightly more expensive than other tire inserts on the market.