MTB Stem Bolts

What are stem bolts and when should I replace them?

These inconspicuous bolts hold your handlebars and clamp the stem to the fork. They are subjected to enormous tensile forces, especially during landings. You should replace them if:

• The heads are rusted or "stripped" (the key no longer grips cleanly).
• You want to save weight (upgrade to Titanium).
• You want to add a color accent (color matching) to your cockpit.

What materials are available?

CrMo Steel

The standard. Extremely high tensile strength, affordable, and robust. However, they can rust over time if the paint is damaged.

Titanium (Ti)

The high-end solution (e.g., from TLC Bikes or Title). Titanium is approx. 40% lighter than steel, completely rust-proof, and extremely strong. Perfect for lightweight builds.

What should I look for in size?

Almost all modern MTB stems use M6 threads. However, there are differences in length and head shape:

• Thread: M6 (metric, 6mm diameter) is standard. M8 is only found on very old or specific BMX stems.
• Length: Measure your old bolts (thread only, without head!). Common lengths are 20mm to 25mm. Bolts that are too short will strip the threads out of the stem!

How do I install stem bolts safely?

1. Lightly grease the threads and the underside of the bolt head. This ensures accurate torque readings.
2. Faceplate (Bar Clamp): Always tighten the 4 bolts in a cross pattern and incrementally so that the gap is even at the top and bottom.
3. Use a high-quality Allen key (usually 5mm or 6mm) to avoid damaging the head.
4. Observe Torque: Only tighten the bolts as tight as specified on the stem (usually 6 Nm). Overtightening can crack the stem faceplate!

What do the specifications mean?