First, mountain bike tires were tubed, then tubeless, and now… tubeless with various inserts. There have been a handful of inserts that have popped up recently which all have similar claims. Namely, that they protect the rim and tire from heavy impacts and should keep you from pinch flatting if you manage to strike a rim.

While one of their main goals is similar, the way they go about it is very different. CushCore is one of the newest tire inserts, but to them, it’s more than just a strip to protect your rim and tire. Instead, they look at CushCore as a inner tire suspension system – which results in a damping element as well as a tunable air spring…

The main component of CushCore is an engineered foam insert in two sizes for 27.5 or 29″ wheels. The insert is designed for 23-33mm internal width rims and has a center section that is designed to sit inside the rim channel between the tire beads. At the moment, the inserts are sized to fit 2.1-2.5″ tires, though plus size version are on the way.

Effectively dividing the tire volume in half, one of the biggest advantages of the system according to CushCore is the fact that the insert supports the sidewalls of the tire from the inside. This supposedly allows you to run lower pressures, while still maintaining needed sidewall support. CushCore recommends initially running 5psi less than normal, and fine tuning from there. Referring to the air pocket as the spring, and the foam insert as the damper, CushCore claims the insert helps deaden vibrations, while also protecting both the tire and the rim during big impacts – especially given the fact that the insert covers the entire rim when compressed. According to their tests, the system offers a 50% reduction in vertical impact force, 77% reduction in lateral vibrations, and a 58% reduction in longitudinal vibrations.

The closed cell foam is said to be compatible with all tubeless sealants and won’t absorb fluid over time.

The other piece of the puzzle is the custom valve for the system which allows air to properly flow through into the rim. Since the insert sits directly over the valve, a traditional valve would be blocked by the insert. Instead, the CushCore valves have holes on the side.

Even though the inserts add some weight to each rim, the added grams are said to be offset by the ability to run lighter tires and rims. We picked up a set for testing at Sea Otter and will have actual weights in a post soon. After launching about a month ago, the CushCore system is available for $149 per set which includes two inserts and two valve cores.


  1. I dont consider myself a weight weenie, but dont you think this post is substantially incomplete without including the weights of these things?

  2. Per company website, 260g apiece for a 29er, 250g for 27.5. I suppose that’s going to scare a lot of folks off. There’s also the getting over the idea of plunking down $150 for two foam rings. Seems a tough sell.

    • I agree entirely, $150 for the product you’re getting is a lot, and 260g is a serious weight gain- but still, I’d like to see a comparative review of these with different tires; if they indeed can help you run lighter tires, the weight gain would be offset and the potential performance increase would might be worth it.
      Tire companies in particular would be able to use recognition of their brand to sell something like this, but haven’t so far on a serious scale. That makes me think it’s because it doesn’t really give big benefits.

    • in theory you can get away with a lighter duty tire and possibly saves some weight. I recently went with the shwalbe procore system and yeah it added weight, but i stopped destroying tires so I’ll deal with it. comfort and grip both increased too by dropping the psi a few notches.

  3. for anyone complaining about weight, price, etc.

    these are targeted at downhillers and enduro racers. Same as flat tire defender, and to a certain extent huck norris.

    the part about this being an “air spring” reeks of marketing nonsense, but having the foam at the rim does manage to take a bit of the “edge” off of impacts, at least according to Aaron Gwin (who’s riding flat tire defender).

    it also helps lower the risk of pinch flats, which when racing (DH or enduro) will end your run pretty quick. so it’s a tradeoff of weight vs risk of flatting.

  4. Would this be good for the Fat Bike market? You could let basically all the air out of your tire and still have a little stability there. Wouldn’t have worry about the rim cutting the hell out of our tire.

    Not sure $150 is reasonable but this might be a baby step towards something.

  5. I guess my role here on BR is to play devil’s advocate on niche products…

    Certainly this isn’t for everyone, but I can think of some great use cases. Bikepacking for instance – if you’re riding across Montana and have 20lbs of tents and food – this seems like an excellent insurance policy. Downhill and Enduro also make sense.

    I would consider these on my CX bike – which is more of a gravel bike for me since I suck at Cross – riding trails with 35MM tires beats the hell out of my rims. I’m far more than 2 pounds overweight and I would ride easier with a little cush between my tires and rims.
    I recently mounted a set of Envy AM 29er rims to my CX ride just to add some strength at that vulnerable spot. make me a set to fit a 35-40mm tire!

  6. $150 for foam, at least tell me it’s ‘Aerogel’ or something fancy sounding, even just putting some info on the actual material used would help sell it. I’m sure it’s something special like ‘High-Pressure Injection Molded Closed-cell Polyurethane Foam Ring’

    • I do… so a lot of other people I know… It also happens to some EWS racers at every race so please do not pull the “pick you lines better” card 🙂 Rims are getting way stiffer with increase the chances of puncturing a tire. I personally ride carbon rim not for the weight saving but the stiffness and ride feels it brings.

  7. Couldn’t I just cut a pool noodle in half length wise and put some kind of cap on my valve so the air can get in? Heck, I have a 3d printer, a knife, and $1.50 for a pool noodle. I think I’ll give it a shot!

  8. They need to apply this product to the cyclocross segment. Being able to run an open tubular clincher at ultra-low pressures and not pinch or roll would easily offset the weight and price

  9. For all you complaining about weight….. I work at a shop and for the most obsessed nation in the world we might want to consider ONE LESS BEER than worry about a little over 200 grams PER WHEEL.

  10. I’ve done a few reviews on these and I’ll post them below. I completely understand the issue with added weight but the fact that you can run a lighter tire and still have such great cornering and rim protection is a plus for me. I still have more to review but thought you might find these interesting.

    CushCore Install Review-

    CushCore Interview-

    Bike Chat with Josh Paterson-

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