Sheldon Brown's

Seatpost Size Database

A- B- C- D- E- F- G- H- I- J- K- L- M- N- O- P- Q- R- S- T- U- V- W- X- Y- Z

This page is a listing of various bicycles, and the seatpost diameters that fit them.

This is too large a project for one person, I need your help!

Dont use the above email link for general email,
because I only look at that mailbox when it's time to do an update on this page.
For general email, use CaptBike@sheldonbrown.com

Accuracy

On a related topic, I have an article on Stuck Seatposts which may be of use to you.

A Few Generalizations:

Most steel bicycles have tubing of standard outside diameter. Frames made to British or Italian standards will typically have 1 1/8" (28.6mm) seat tubes. Older French bicycles used 28mm. Old American style, commonly used on BMX bicycles and other bicycles that use one-piece-cranks, uses a 1" seat tube. Standard outside diameter accommodates standard lugs and clamp-on parts such as front derailers, pulleys and other cable guides, pump pegs, etc. High performance bicycles are made of thinner tubing, so the hole will be larger if the outside diameter is kept the same.

As a result, a larger seatpost size is often a sign of a higher quality bicycle. This has resulted in a de facto standard of 27.2mm for high quality bicycles that have 1 1/8 O.D. seat tubes. Since high quality seatposts are widely available in 27.2, most high end aluminum and carbon fiber road bicycles also use 27.2. A recent trend to oversized tubing has resulted in the introduction of oversized seatposts (anything over 27.4 would be considered oversized.) These are more commonly seen on mountain bikes, where the longer seatposts commonly used can use the extra strength.

Thanks to those who helped by providing data points for this survey:

Visitor # since December, 1996

Copyright © 1997, Sheldon C. Brown

E-Mail: CaptBike@sheldonbrown.com

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