Road stems

How to choose a road bike stem

The stem is the cheapest component that makes the biggest difference to your riding position. Three measurements define it — length, angle and diameters — and the last two are the ones people get wrong most often.

Length

From 60 to 140 mm, in 10 mm increments. Length determines your reach: a longer stem moves your torso forwards and takes weight off the front of the bike; a shorter one puts you more upright and makes the steering more responsive. You’ll feel a 10 mm change immediately. If you’re unsure after changing handlebars, remember that the handlebar reach adds to the stem’s reach: compact handlebars fitted with the same stem already bring you 10 to 15 mm closer.

Angle

• ±6 to ±7° : the standard angle. Flip the stem and it goes from downward- to upward-angled, raising the handlebars by around 20 mm — the most effective free adjustment you can make to your bike.
• ±17° : to follow the angle of a laid-back head tube, or raise the handlebars substantially without stacking spacers.
• ±30 to ±35° : a pronounced upward angle for touring and long-distance riding positions.
• The adjustable stems (Ritchey 4-Axis, PRO LT) let you find the right angle before settling on a fixed stem. Useful after changing bikes or having a bike fit.

The two diameters to check

• At the fork steerer : 1"1/8 (28.6 mm) is standard; 1" (25.4 mm) is also found on older frames, as is 1"1/4 (31.8 mm).
• At the handlebars : 31.8 mm today, with 26 mm on some Deda models.
• The two are independent: a stem can fit your fork but not your handlebars. It’s the most common mistake when choosing a stem.

Adapters and shims

The range includes reducer shims — 31.8 to 28.6 mm, 28.6 to 25.4 mm — and threaded steerer-to-Ahead-Set adapters, which let you fit a modern stem to a quill-type fork. These parts help with an older setup; they are no substitute for a stem with the right dimensions.

Internally routed stems

The models DCR (Deda), ACR and SCR (FSA) route cables and hydraulic hoses internally towards the headset. They only work with the handlebars, headset and spacers specified by the same brand. Treat them as a complete system, not a standalone part.

The bolts

Replacement bolt kits must be ordered using the exact model reference. With carbon handlebars, a torque wrench is essential : the faceplate torque is generally 5 Nm, and it’s the handlebars that break, not the bolt.

To find out more: How to choose your road bike stem

See also: Road handlebars · Headset spacers · Top caps and expanders