FSA OS-120 1-1/4in stem review£49.95

Say goodbye to loose headsets on your 'cross bike

BikeRadar score4/5

FSA don't bill the 1-1/4in version of their OS-120 stem as a cyclo-cross specific item but they may as well do since it's practically purpose-built for the job, especially for racers on carbon steerer tubes. 

The key is the included aluminum shim, which steps the steerer diameter down to the 1 1/8in standard and lends a grippier and more solid clamping surface than bare carbon. 

This makes gradually loosening headsets (as a result of gradually slipping stems) on rough terrain a thing of the past, and the shim's offset slot is very effective at preventing crimping too.

The forged alloy extension and body is sufficiently stout, and the four-plate alloy faceplate lends extra security on the handlebar end – both good things to keep at the back of your head as you're remounting at top speed after a set of barriers.

However, all that extra clamping power does have a cost as our 100mm-long sample weighs a comparatively heavy 175g.

While there are heaps of other stems out there that are far lighter, not many work quite as well for this specific application (though Syntace's similarly shimmed – but more expensive – F119 comes to mind). Skip it if you haven't had headset issues but this might be the answer to your prayers otherwise.

James Huang

Former Technical Editor, US
James was BikeRadar's US tech editor from 2007-2015.
  • Age: 40
  • Height: 173cm / 5'8"
  • Weight: 70kg / 154lb
  • 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, CO, USA
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