Pinched seat tube?

Built this frame up early last year and wasn't sure of the seat post size. It measured up as just over 27mm but a 27.2 just wouldn't go it whereas a 27.0 seemed to fit nicely. I ended up only riding this bike for a few months and then had to put it into storage when I moved house.

Since getting it back out of storage I have noticed that the seat tube cluster appears to slightly pinched (see pics below). So is this a problem that i need to worry about and Is it likely to get any worse and if so what would need to be done to get it repaired?

Anyone got a view on this issue?

Not an expert, but - it is possible it was 27.2, but had already been pinched (why 27.2 wouldn't fit). Putting 27 in may have resulted in it being pinched more.

I have no idea what the long term effects of this could be.

this is something that is happening to me!
every seat bolt snaps eventually, really annoying, bolts have to be super short yadda yadda!
steel appears to be pinched. very annoying.
anyone with any insight into how to improve this would be amazing.

i used to do the old screw driver trick. get an old screw driver (flat head with a thick shank) and prise it open between the lugs (the seat bolt lugs). be carefull and it should work fine. its suprising what abuse a frame can take. then once its open see if the 27.2 will fit in.

or use one of these and put it in to where the seat/top/stays all meet and measure from there as that area is the least likely to deform and mess with your sizes. a decent engineersor maybe even frame builders should have one they may do it for you..

oh and no, if its holding your post firm then its not too uch of a proble. its only if the post is too small that the bolt has to be done up way to tight and it deforms the metal and/or the gap closes up and touches that its really a big issue. its just better to have the correct post in it so this doesnt happen.

as for bolt snapping, sounds like you have poor quality bolts and/or the gap is closed up fully and the bolt is being put under way too much stress trying to hold the post in place.

I've got some calipers will try measuring the inside of the tube lower down.

Prying open with a screwdriver might be an idea but I guess that might fuck the paintwork and or the lug.

The bolt seems to hold the post okay so maybe I will just leave it for now.

has one of the lugs got a thread in it? if so, remove the bolt and put it in from the other side. insert a flat bit of metal in the gap (large washer/blade of screw driver or similar) and tighten the bolt onto it so that as you do the bolt up it pushes the other side out. using this method is less stressfull on the paintwork but only possibleif the lug has a thread... hope that makes sense.

Yep, pretty sure this is what happened to my seat tube, too. Research told me the pearl white Gazelle Champion Mondial track frame should be 27.2 but 27.2 definitely did not fit in. I just had to tighten the bolt down what seemed a ridiculous amount, so had a gander and...looks pinched! Gah! I'm having so much trouble with this area of my bike lately!

Thread dredge.

Just bought a second hand 60's track frame and it appears to have this problem. With callipers it measure almost 27.2 side to side and around 26.8ish back to front. Bit annoyed as the bloody forks were out of alignment too.

What are my options? I don't have a 27 or 26.8 seat tube to try out. Should I give it a going over with a screw driver?

I think words with the ebay seller are in order too. I am dissapoint.

I thought my post was meant to be 26.8 after measuring one. Bought a post, fitted it but no matter how tight the bolt was it wouldn't stop turning. Opened up the clamp and a 27mm post slipped straight in. I'd suggest you open up the clamp then try a few posts. Id doubt you'd do too much harm in opening it up so long as you're careful

Do you know what the frame is? You might be able to find out what those frames are meant to be.

Its a Sid Mottram from 1964, built by Mercian. This is going by the serial number and the fact the seller bought it from Mottrams...

I need to get hold of a few seat posts I guess.

An LBS should have a few you can try

Good point, worth a try :)