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www.pinkbike.com

This 3-Piece Foam Tire Insert Replaces Air - Taipei Cycle Show 2019

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Has the insert game gone too far? This three-piece modular insert completely replaces the air that'd normally fill your tires.
Tire inserts are all the rage right now, with riders stuffing all sorts of strange looking contraptions in between their rim and rubber in an effort to come up with a flat-proof system. But if you don't want the air to escape, why not just skip pumping it in there in the first place and go down a different road? Solid tire inserts aren't new by any stretch, but they've pretty much all been simple tubes of something or other that weigh a ton and, when you ride on them, feel like total shit.
The 29'' x 2.8'' models weighs 505-grams and a set goes for $125 USD.
Air Fōm's modular, three-part insets look like they're a long way from those simple inserts, though, and the new company is aiming to have riders think of their product as a high-end option for performance bikes. They'll have a ton of different sizes available, but the 29'' x 2.8'' version pictured here is said to weigh 505-grams, and $125 USD will get you enough to do two wheels. So, why three different layers? Air Fōm went that route because each piece has a very different job, and they're made of very different materials, too. The outer blue-colored stuff is ETPU foam, or expanded thermoplastic urethane if you want to be proper about it, and its job is to mimic the feel of a traditional air-filled tire. I was told that it offers a high energy return or, in simpler terms, is soft and rebound quickly. It's also not brittle at all - I watched a section be bent nearly in half without issue - and is said to be nearly indestructible under the kind of abuse that mountain bikers would put it through. The closed-cell foam feels almost rubber-like, is apparently immune to temperature changes, and nothing like you'd expect from looking at photos.
Not your average tire insert, with the different colored sections each responsible for a different job.
The base layer - that grey stuff - is EPP foam, AKA expanded polypropylene, and it's how Air Fōm tunes the insert's ride characteristics. It sits up against the rim, with the white-colored joining section between it and the blue ETPU foam, and different densities can be installed to mimic pressures between 22 and 25 PSI. And speaking of installation, Air Fōm claims that while it's certainly more difficult than normal tubeless setups, the job should only take ten-minutes per end. Picking the right size for your needs is something that a bike shop might need to do, Air Fōm says, because it takes into account diameter (of course), tire size and volume, and internal rim width. There are three different sizes for 29ers and three for 27.5, ranging from 2.35'' to 2.75'', and seven to choose from if you need a set for your road, cyclocross, or gravel bike.
The inserts are split into four sections for shipping and to ease installation.
So, what do you guys think? Would you give 'em a try?