Gear Watch: Square Bike Tubes

The Michelin Man has unveiled his latest creation: the Michelin Michelin Protek Max. It's a tube for your bike tire with some unusual qualities. First, it's square in cross-section. Second, it's dimpled with raised circles on three sides. Third, these features combine to give it the ability to self-seal in the event of a puncture, reducing the chances of a blowout on your next ride.

When a traditional bike tube is punctured, the air pressure inside creates an expansive force on the hole. This "balloon effect" can increase the size of the puncture and lead to rapid deflation. In contrast, the Protek Max is engineered to instead create a compressive force on the puncture that can reduce its size and even seal it closed. The inside of the tube is coated with a layer of sealant, as well, further amplifying this effect.

Here's a mock-up from Michelin illustrating the effect.

Michelin also claims that the square shape of the tube allows it to naturally sit in proper position. No more worming a twisty sausage shaped tube into position. The Protek Max is currently available with Presta or Schrader valves for both road bikes (sizes 700 x 35-47c) and mountain and other wide-tire bikes (26 x 1.4-2.125 inches). It retails for around $8.

Equipped” is an AMC Outdoors blog, written by Matt Heid.

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