FSA OS-120 1-1/4in stem review

Say goodbye to loose headsets on your 'cross bike

Our rating 
4.0 out of 5 star rating 4.0
GBP £49.95 RRP | USD $76.99

Our review

Slip-free clamp on 1-1/8in steerers with included shim, sturdy four-bolt alloy faceplate, low stack height and reasonable cost, but heavier than true race-level stems
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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.

Product Specifications


Name OS-120 Stem
Brand FSA

Features Weight listed is for 100mm stem
Weight (g) 175
Stem Rise 6
Material 2014 Aluminium Carbon Fibre Chromoly Steel
Stem Length/Reach Options 100mm 110mm 120mm 130mm 80mm 90mm
Stem Size Compatibility 1 - 1/8 In