Re: [CR] Caring for a Teledyne / seatpost fit

(Example: Framebuilders:Masi)

From: "David Snyder" <dddd@pacbell.net>
To: "Classic Rendezvous" <classicrendezvous@bikelist.org>
Subject: Re: [CR] Caring for a Teledyne / seatpost fit
Date: Tue, 29 Apr 2008 20:49:14 -0800


" I have a 26.8 seat post in the seat tube right now but appears a?just a tad?loose.? Is that the right seat post ?size for the frame?? "

Whenever I want to determine if a seatpost is one size (or more) too small, I'll put an almost-360-degree wrap of soda can shim part-way into the seat tube and then try to fit the post in question.

Current 12oz cans measure very close to .004" (or 0.1mm) thick, so a full wrap adds 0.2mm to the post's diameter and thus simulates the fit of a next-size-larger post. (7-UP brand, btw) Larger-volume cans are thicker.

Measuring seat tube ID directly is complicated by a lack of roundness and by any flaring or other distortion present, and one should also never expect a seatpost to measure full size, as most are a bit under by as much as 0.1mm being not uncommon.

Test-fitting with the 0.1mm shim thus only will guarantee fit of same-branded, one-size-larger post, but is still a somewhat-reliable measure for different-branded posts. Campy and SR are just two of many brands I've found to be relatively undersized, with Avocet and American Classic being much more true-to-size.

If the 0.2mm-bigger post fits, it should be used imo, or one can leave the shim in place as a temporary fix.

The Teledyne is THE bike to have when you must store it under sea water.

David Snyder
Auburn, CA usa