Seat Clamps
Used MTB seat clamps from UK sellers, plus new stock from Hope, Wolf Tooth, Race Face, Nukeproof, Burgtec and Chromag. The seat clamp is the collar that clamps around the top of the seat tube to secure your seatpost, and comes in quick-release and bolt-up designs.
What does a seat clamp do?
The seat clamp is one of the simplest MTB components — a collar that tightens around the seat tube to hold the seatpost in place. Getting the right diameter is the only critical compatibility factor, but clamp design affects security, weight and ease of adjustment.
What diameter do you need?
The seat clamp diameter matches the outside diameter of your seat tube at the top, not the seatpost diameter. Common sizes are 34.9mm (fits frames with a 31.6mm seatpost), 36.4mm (fits some 31.6mm frames with thicker tube walls) and 38.6mm (fits 34.9mm seatpost frames). Measure the outside of the seat tube where the clamp sits, or check your frame's spec sheet — a clamp that's too small won't close around the tube, and one that's too large won't grip properly.
Quick-release or bolt-on?
Quick-release (QR) clamps have a lever for tool-free adjustment, useful if you frequently adjust saddle height, though a dropper post makes this redundant. Bolt-on clamps use a single M5 or M6 bolt tightened with an Allen key, so they're lighter, lower profile and more secure against theft. With dropper posts now standard, most riders run bolt-on clamps because the saddle height never needs manual adjustment.
Which material is worth paying for?
Alloy clamps from brands like Hope, Wolf Tooth and Burgtec weigh 15-25g and come in anodised colours to match your build. Carbon clamps save a few grams but are overkill — the weight saving is insignificant and carbon doesn't clamp as confidently around a round tube. Stainless steel bolts resist corrosion better than standard steel, worth having if you ride in UK winter conditions year-round.
How do you stop a seat clamp creaking?
A creaking seat clamp is one of the most annoying sounds on a bike, and it's almost always caused by insufficient clamp force or a dry interface. Clean the seatpost and seat tube bore, apply a thin layer of carbon paste (even on alloy posts — the friction compound helps grip at lower torque), and tighten to the specified torque with a torque wrench. If it still creaks, check for frame flex at the seat tube junction — some frames creak at the weld rather than the clamp.