Bicycles

Foam insert puts a damper on bouncy bike tires

Foam insert puts a damper on b...
A cut-away view of the CushCore insert, on display at Interbike 
A cut-away view of the CushCore insert, on display at Interbike 
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A cut-away view of the CushCore insert, on display at Interbike 
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A cut-away view of the CushCore insert, on display at Interbike 
A set of two CushCore inserts will cost you US$149
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A set of two CushCore inserts will cost you US$149

Most mountain bikers wouldn't want shock absorbers that were simply springy air chambers with no damping. According to the guys at CushCore, however, that's exactly what tires are. Their solution? An energy-absorbing foam insert that sits inside a tubeless tire, acting as a damper while also adding flat protection and improving cornering.

The CushCore insert only occupies half of the space inside the tire, leaving an air pocket underneath the tread – the air pressure is set by the rider using a standard pump. That pocket acts as a tuneable spring, while the closed-cell foam insert serves as a damper. The setup reportedly makes the tire less likely to bounce off of obstacles such as rocks and roots, resulting in a smoother ride.

Additionally, the insert protects against pinch flats. In fact, riders can improve traction by running their tires at a lower air pressure than would ordinarily be possible. What's more, if the rider does get a flat, the insert reportedly provides enough support for them to still limp home with no air in the tire. The system is sealant-compatible.

A set of two CushCore inserts will cost you US$149
A set of two CushCore inserts will cost you US$149

Finally, the insert is claimed to add lateral stability to the inner portion of the tire, where it hooks onto the rim. This is said to keep the tire from squirming sideways relative to the rim while cornering, resulting in increased sidewall stability and lessening the chances of the tire "burping" right off the rim.

But yes, there is a bit of a weight penalty. An insert for a 27.5-inch tire tips the scales at about 250 grams, while a 29-inch insert weighs 265 g.

A set of two will cost you US$149. By contrast, Schwalbe's Procore system, which utilizes a high-pressure inner tube instead of a foam insert, costs about $230 per set.

There's more information in the video below.

Source: CushCore

CushCore Introduction

5 comments
BeinThayer
Making a tire rebound less means removing energy (or perhaps just delays return of energy) very time the tire is compressed. The tire is compressed continually as it rolls and this dampening of rebound will translate to more rolling resistance as the energy used compressing the tire is not returned in time to assist the forward motion. Thus could be good for downhill races. It will, however, make it more difficult to attain the same speed going uphill or even level.
akarp
@ BeinTHayer, correct from the video CushCore claim only 3% rolling resistance increase. Not sure how noticable that efect would be.
ljaques
They add weight (small) and rolling resistance (3% is significant IMHO), and rolling resistance creates heat/wear, so where is the benefit? Those are 3 negative features. 2 positive features are the added strike resistance and added lateral stability with lower air pressures. Figure in the ghastly price, and it reduces all possibility of a sane person buying a pair. At $50, they'd still be overpriced but CushCore would likely sell 10,000 pairs. At triple that, they'll be knocked off in Chaiwan with stinky godknowstheingredients rubber in no time.
noteugene
Instead of spending 180 bucks why cant i just go to wal mart and get 5 a can stuff that's similar enough in composition? Also won't have to spend 180 on a mimi fema pump....
Albert L
I've had great experience with Bell Sports Cycle Products 7015332 26" No-Mor Flats Bicycle Inner Tube or stop-a-flat may work as well and cost less. Doubt they come in bigger thatn 26 and may be out of production?