PREVENT FLATS AND IMPROVE YOUR RIDE

Over the past decade, 29-inch wheels, bicycle-geometry evolution, and improved suspension performance have increased the speed at which we ride our mountain bikes. Meanwhile, the gravel revolution has us riding our unsuspended drop-bar bikes farther off the asphalt and onto rougher roads and trails. As a result, we're hitting things harder, which takes a toll on our wheels and tires.

- MATT PHILLIPS

We've also seen the widespread adoption of tubeless, the use of hookless rims, and the embrace of wider tires. Brands constantly launch new wheels and tires, claiming they're the lightest, grippiest, toughest, fastest, or bestest.

Along with noise about wheels and. tires is new momentum around something that's neither a wheel nor a tire but that interacts with both: tire inserts.

The modern iteration is a hoop of foam that lives inside a tubeless tire. These inserts can fit all types of bikes, from roadrace bikes to downhill MTBs and everything in between and adjacent. For race use, inserts are most often seen inside the tires of mountain bike and gravel pros. There are some road races, however-the Spring Classics, and especially Paris-Roubaix-where an insert could be advantageous, as the roads in play are notoriously tough on tires. Inserts can benefit everyone from the top pros to more casual riders.

The advantage that unifies most tire inserts is flat protection. In a hard impact, an insert functions as a bump-stop, preventing the tire's casing from folding and bottoming against the rim, a situation that often causes a pinch flat. This protection also cuts down on rim strikes that can dent aluminum rims or break a carbon one.

But if you get a flat when using a tire insert, the other benefits kick in. Some inserts lock the tire onto the rim; this. allows the rider to maintain control of the bike, protects the rim from getting chewed up, and prevents the flat tire from peeling off and jamming into the frame.

At the same time, the insert partially supports the tire. This run-flat capability enables gravity racers to complete their runs at nearly full speed or allows road or cross-country racers to keep moving and finish a race without stopping.