Revised ultralight mountain bike stem from Rotor

SL2 has stiffer shape plus new steerer tube clamp

Rotor have updated their ultralight SL mountain bike stem with a stiffer shape plus a new steerer tube clamp design borrowed from their 3D crank.

The extension has been changed from a straight cylinder to a heavily milled-out conical cross-section for better torsional rigidity, which is similar to what the company have already done with their impressive S1 and S1X stems. 

Though this has added a few grammes, total claimed weight remains a feathery 91g for a 90mm length (and still just 102g for a 120mm). 

Rotor carry over the existing version's two-bolt removable face plate but the steerer clamp is now a single-fastener setup with a much larger bolt than before. This supposedly yields more evenly distributed clamp pressure on the steerer, and the threads are replaceable in the event of overtightening. All bolts use Rotor's slick dual thread pitch DTT Evo bolts with Torx heads. 

The SL2 stem will be available in 90, 105 and 120mm lengths, all with a reversible six-degree angle and traditional (non-oversize) 25.4mm mountain bike bar clamp diameter only. Rotor say a 31.8mm version will be unveiled at Sea Otter and other stems will soon be updated with the new single-bolt steerer clamp.

The single-bolt clamp hardware is borrowed from rotor's 3d crankset: the single-bolt clamp hardware is borrowed from rotor's 3d crankset

James Huang

Technical Editor, US
James started as a roadie in 1990 with his high school team but switched to dirt in 1994 and has enjoyed both ever since. Anything that comes through his hands is bound to be taken apart, and those hands still sometimes smell like fork oil even though he retired from shop life in 2007. He prefers manual over automatic, fizzy over still, and the right way over the easy way.
  • Discipline: Mountain, road, cyclocross
  • Preferred Terrain: Up in the Colorado high-country where the singletrack is still single, the dirt is still brown, and the aspens are in full bloom. Also, those perfect stretches of pavement where the road snakes across the mountainside like an artist's paintbrush.
  • Beer of Choice: Mexican Coke
  • Location: Boulder, Colorado, USA

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