tight seatpin

secretsam

So - old 531 now sprayed, got it a nice new seatpin, in the usual massive 300mm length, thought it was right size (27.2mm) but when I come to fit it it's a right tight squeeze. More lube than in a p0rn film but still took some doing to get the damn thing in...

The old 531 was a little, er, corroded, which the new paint and blast cleaning sorted on the outside - might it need a little clean up on the inside of the seat tube? The old seat pin was one of those F****ng stupid 'fluted' jobs, popular back in the '80s, which was letting water drip down the seattube it would seem, so there may be a bit of tin worm down there.

Any wise thoughts?

UndercoverElephant

Vernier caliper?

EKE_38BPM

Wrap a piece of paper around the seat post at an angle and mark a line across the two surfaces of the paper. Unwind the paper and measure the distance between the two marks to get the seatpost's circumference. Do a bit of maths and you can convert the circumference to the diameter that you actually want.

Ben6899

Is it definitely a 27.2mm that you require? And not a 26.8(or 6)mm?

rolf_f

SecretSam wrote:

The old seat pin was one of those F****ng stupid 'fluted' jobs, popular back in the '80s, which was letting water drip down the seattube it would seem, so there may be a bit of tin worm down there.

Just on this - the flutes are (or should be) closed at the bottom so in the unlikely event that much water did manage to get into the flutes, it wouldn't have anywhere to go. And then it probably wouldn't cause much corrosion as the water would be able to evaporate and 531 needs to work hard to corrode - particularly if smeared from the grease that obviously you would have applied to the pin before inserting! I'm not sure there is anything much wrong with fluted seat pins - save weight and look cool!

If the old pin fitted easily, and the new pin is tight, then the new pin is larger than the old - you can't blame the seat tube for that!

gtvlusso

Some 531 frames are 27.0 seatpins...... Particularly continental and some Raleigh race frames.

27.0 is an old Campag standard, I think! So, if the old seatpin was fluted, it could indicate a quality design like Campag......

secretsam

Hmmmm...no, old 531 is not foreign (built locally in Bristol by an unnamed builder) and seatpin was one of those cheap pole + clamp jobs that were so common back in the day!

Am worried I've got a weird frame tube diameter, however...

gtvlusso

SecretSam wrote:

Hmmmm...no, old 531 is not foreign (built locally in Bristol by an unnamed builder) and seatpin was one of those cheap pole + clamp jobs that were so common back in the day!

Am worried I've got a weird frame tube diameter, however...

If it was built in Bristol, it could be Argos (www.argoscycles.co.uk) - Anything old and steel that was built for Campagnolo will probably have a 27.0 seatpin and not 27.2.

My Raleigh 853 Special Products was built for the Raleigh team in the 90's was a 27.0 seatpin - built for campag groupset.





A vernier calliper is the only way to be sure.

secretsam

gtvlusso wrote:

If it was built in Bristol, it could be Argos (http://www.argoscycles.co.uk) - Anything old and steel that was built for Campagnolo will probably have a 27.0 seatpin and not 27.2.

Unlikely to be Argos, it wasn't that expensive (£150 in 1986ish) - there were a few builders in Bristol back then, eg Dan Shotton, Overbury's were doing their own, may have been a local framebuilder knocking out a few frames for a few bob. Was sold by Bike Tech, who used to be at the bottom of Park St.

Anyhow, will have to get it measured...the old seatpin is still around so may drop that back in!

gtvlusso

SecretSam wrote:

gtvlusso wrote:

If it was built in Bristol, it could be Argos (http://www.argoscycles.co.uk) - Anything old and steel that was built for Campagnolo will probably have a 27.0 seatpin and not 27.2.

Unlikely to be Argos, it wasn't that expensive (£150 in 1986ish) - there were a few builders in Bristol back then, eg Dan Shotton, Overbury's were doing their own, may have been a local framebuilder knocking out a few frames for a few bob. Was sold by Bike Tech, who used to be at the bottom of Park St.

Anyhow, will have to get it measured...the old seatpin is still around so may drop that back in!

Not heard of Dan Shotton, but I think that Fred Baker knocked out some very high quality stuff back in the day from Bristol - the Shop is still on Stokes Croft, if you have the frame number it may be worth a ring around Overburys or Fred Bakers.

I managed to get hold of the Guy that built my Barron frames back in the 70's and 80's in Lincolnshire (Barry Barron) - he gave me all the details on the frames including who it was built for an what races it competed in!

spen666

tight seatpin?

I'm guessing its from Scotland or Yorkshire