How do I know what size seatpost clamp I need?

Note: The seat clamp diameter needs to match the diameter of your seat tube rather than your seatpost, which is a little smaller. For example, a 27.2mm seatpost (a size commonly found on road bikes) fits inside a 28.6mm diameter seat tube, so it’s a 28.6mm clamp you need.

What are seatpost sizes?

Seatpost diameters generally range from 22 mm to 35 mm in 0.2 mm increments. The most common size is 27.2 mm (1.07 in) for most bikes, especially for the higher-quality models. BMX bikes commonly use 25.4 seatposts. In some modern bikes with thicker alloy or carbon tubing, larger diameters such as 30.9 mm are used.

How big does A seatpost clamp need to be?

Frames may vary slightly from the nominal diameters due to tolerances and paint thickness. Clamps will fit on frames that are within +/- 0.5mm of specified size. For example, a 34.9mm clamp will fit frames with a seat tube measuring from 34.4mm to 35.4mm in diameter.

How big is the seat clamp on a bike?

Diameter of the seatpost cant be accurately used to detetminr the seat clamp size. My seatpost is 30.9, seat clamp is 34.9. what bike does the OP have?

How big is a wolf tooth Seatpost clamp?

Machined from 6061 aluminum in our Minneapolis facility, the Wolf Tooth Seatpost Clamp is available in six sizes and a variety of anodized colors. Frames may vary slightly from the nominal diameters due to tolerances and paint thickness. Clamps will fit on frames that are within +/- 0.5mm of specified size.

How big is the seatpost on a BMX bike?

Old US bicycles (mostly BMX and older bikes that used one-piece cranks) was 1″ (25.4 mm). Standard outer diameter dimensions were important so that derailleur clamps etc. could be made in exact matching sizes (derailleur clamp inner diameter needs to match the seat tube’s outer diameter).