Dawes Bikes '94 era seatpost size

[dablk]

Jus picked up a 1994 special edition., 501 frame.

Seat post has a bad insert marks. It reads 27.0. Picked up temp new replacement and that's going to be a jam to get it in but I can probably do it.

Appreciate this all suggest something smaller.

Anyone know for sure? 26.8?

Many thanks
Chris

 

[hamster]

OK, three things affect seatpost size - nominal tube inner diameter (duh!), seat tube ovalisation from heat stresses left after the frame is built and finally seatpost tolerances. It's not unusual for an ovalised seat tube to take a smaller post, but the fact that a 27.0 post fits shows it's very close.

Firstly clean the seat tube inside carefully - then add a smear of grease to the tube and try it again.

 

[lensmansteve]

I have several 501 bikes, 27.0 mm is a good fit on most, but tolerances in the frame and seatpost dimensions mean that some 27.0 posts fit certain frames better!
It's worth checking the frame for distortion, both ovalising caused by mechanical stresses, and of the clamping slot area, caused by overtightening and/or a fractionally undersized post.. Just to confirm- a 26.8mm post is slack for all of my 501 frames..

 

[dablk]

Thank you all,
Will have a closer look.