Mavic EN 421 Disc Rim


Mavic EN 421 Disc MTB Rim UST is the proven benchmark for tubeless technology. The EN 421 Disc makes it available to everyone. Its unique patented internal shape makes the tyre easy to operate. The 21 mm width makes it perfect for Enduro riding. Features: 6106 aluminum alloy Pinned Traditional drilling Single eyelet UST Tubeless or Tubetype Disc Weight: 550 grams (26'') Dimensions: ETRTO size 26 : 559 x 21 Recommended tyre widths: 2.00 to 2.50 Valve hole diameter: 8.5 mm, supplied with valve adapter Recommended nipple length: 12 mm Recommended rim tape: Mavic UST rim tape Technologies: UST TUBELESS READY: Traction, control and lightweight The UST concept improves traction, control and comfort while reducing inertia and flats. The 'tubeless ready' construction results in a lighter tyre for improved performance. Buy Mavic Rims from Chain Reaction Cycles, the World rsquo;s Largest Online Bike Store.


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[May 02, 2019]


Mavic EN421's are marketed as UST compatible and I can tell you for certain that they are not. I tried everything to make these rims run tubeless with zero luck. I put the dedicated Mavic rim strip in and it wouldn't hold pressure for long, even with Orange sealant. Not to mention, when the rim strip is used, it was impossible to mount my Michelin Wild Gripr tires without metal tire irons. I tried a pair of Specialized S Works tires and it was still a major PITA to mount. I have mounted tires for on bikes for at least 40 years and this was the most miserable experience I have had in doing so. I swore more than I ever had trying to get the tires mounted. I then took the strip out and used Stan's tape with a double layer but still no success. (zero bubbles in the tape) It was still leaking out of the valve hole. I tried the Stan's valves first, leaking, then Mavic stems and it was still leaking, even after another round of applying rim tape. I then took out the included adapter shim for the presta valve and put in a tubeless schrader valve and had some minor success, but then realized sealant was still leaking out of the bead here and there during heavy trail riding. I lost about 10 lbs of air pressure in one ride. I finally said F it and put tubes in. No wonder you can't find anything on these garbage rims online. Most of them are probably in a dumpster! Bottom line, they run good with tubes but not tubeless.


I don't care what they are marketed as, they are useless as tubeless. I rated these rims one star because they work fine with tubes.

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