The Air-Liner is a high-quality polymer insert that replaces a portion of the air volume in the tire. This trait, combined with the shape, provides a tunable system that enhances your ride performance. The Air-Liner sidesteps the traditional compromise of stability vs. grip and allows your tires to remain stable, grippy, and controlled, even at low pressures. The Air-Liner is designed using a round cross-section with channels on the top and bottom. 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. 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. The round cross-section shape mimics the natural shape of the tire and supports a greater contact area within the sidewalls of the tire casing. Side-to-side tire stability is increased, yet the tread remains soft and grippy. This improves cornering, climbing, and braking performance.