24 to 39 grams per insert, depending on size. That's less than the sealant already inside your tire, which makes Vittoria's Air-Liner Road one of the few tire inserts that roadies can justify on a weight-conscious build. The high-density polymer construction compresses under the 80-100+ psi pressures typical of road setups, so it doesn't interfere with your tire's intended ride characteristics. The insert essentially disappears during normal riding, letting the casing and compound do their job while sitting ready to intervene if something goes wrong.

When air pressure drops from a puncture, the polymer expands to fill the void inside the tire. That expansion locks the bead against the rim and creates enough structure to keep riding at moderate speeds for up to 50 kilometers. Instead of stopping to patch a sidewall cut or calling for a pickup, you can soft-pedal back to the car or finish a ride. The run-flat capability works even with significant air loss, though the ride quality obviously changes when you're running on foam rather than air pressure.

The insert also enables lower tire pressures during normal riding without the burping and rim strike risks that usually come with dropping psi. Lower pressure means the tire conforms to road imperfections rather than bouncing over them, which translates to reduced rolling resistance on rough surfaces and less vibration transmitted to your hands. Riders on chipseal, cracked pavement, or poorly maintained roads notice the difference immediately. The bead lock function keeps the tire seated even when pressures drop into ranges that would normally cause problems.... Read More