Bike clamps

Seat clamp with screw or lever: what to use

The seat clamp surrounds the top of the seat tube, which is split at that point, and tightens it around the post. The screw clamp, closed with a hex bolt, is light and unobtrusive; it's suitable for road or city bikes where the saddle height never changes, and it prevents the post from being stolen. The lever clamp, or quick release, is adjusted by hand: for a long time it was the standard in mountain biking for lowering the saddle before a descent, but since the advent of dropper posts, it remains practical on a family shared bike. On a child's bike that grows quickly, it also allows for raising the saddle in just a few seconds.

The other components

The components also come in different types:

• Seat posts.
• Saddles.
• Adapters.
• Spacers.
• Washers.
• Stems.

All the components are gathered on the peripheral components page.

Measuring the outer diameter of the tube

The clamp is chosen based on the outer diameter of the seat tube, and not based on that of the post, which is smaller. The most common values are twenty-eight point six, thirty-one point eight, thirty-four point nine, and thirty-five millimetres, but older steel frames and children's bikes may have different measurements. Measure with a caliper, just below the slot. A clamp that is too wide will rotate around the tube without tightening; if it's too narrow, it won't fit. Frames with built-in tightening, which are becoming more common on road bikes, do away with external clamps and use a wedge housed in the tube.

Torque settings and carbon frames

The torque setting is engraved on most clamps, generally around five newton-metres. On a frame or post made of carbon, it should be adhered to with a torque wrench: exceeding this can crush the fibres and cause an invisible crack. A mounting paste with microbeads increases grip between the post and tube, allowing the saddle to be held with a more moderate tightening. On an aluminium or steel frame, a thin layer of grease on the post prevents it from seizing in the tube over time and with moisture.

Good deals

Good deals can also be found in good deals, promotions, clearance, sales, and Black Friday. The new arrivals feature the latest collections, and items shipped in 24 hours are prepared and dispatched within 24 hours. The highlights of the year follow a stable order: Black Friday at the end of autumn, the end-of-year holidays, the winter sales, the French Days in spring, then the summer sales and back-to-school.

Frequently asked questions

How do I prevent my saddle from being stolen?

Replace the lever clamp with a screw clamp, or even with a theft-proof clamp that can only be opened with a specific key. A rushed thief will give up on a saddle he can't remove by hand.

Why is my seat post creaking?

A creak often comes from a dry contact between the post and tube, or from a dirty clamp. Disassemble, clean, apply grease to metal or mounting paste to carbon, then retighten to the specified torque.

What clamp should I use for a child's bike?

A lever clamp makes frequent adjustments easier as the child grows. Check the tube diameter, which is often smaller than on an adult bike, and regularly check that the saddle isn't turning.

What is the purpose of a front derailleur clamp?

On a frame without a welded mount, this clamp surrounds the seat tube and holds the front derailleur. It should be chosen based on the exact diameter of the tube to maintain precise alignment of the derailleur.

Do I need to change the clamp when changing the seat post?

Not if the frame remains the same: the clamp depends on the outer diameter of the tube, not the post. However, it should be replaced if it is cracked, deformed, or if its screw has lost its threading.