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[Closed] Seat post diameter for a vintage BSO - is there a likely standard?

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So I picked up a £35 "bargain" BSO on eBay for a buddy who is getting into cycling (very very early days and he is fairly potless) however sadly the seatpost saddle clamp is a bit borked when used in anger so I am trying to source a new post (and prob saddle) for him.

He doesn't live that close to me so he has measured the existing post as best he can. It appears to be around 24-25mm, is there likely to be a standard seatpost diameter for this sort of bike with a steel frame? I'd hoped that it would be 27.2mm since I have a spare of one of those but it does look less than that... Thanks for any help.

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Posted : 06/08/2017 1:29 pm
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I'd guess at 25.4 mm but does need to be measured properly


 
Posted : 06/08/2017 1:36 pm
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I'd guess at 25.4 mm but does need to be measured properly

Which is 1", durr, of course. Thanks.


 
Posted : 06/08/2017 1:39 pm
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Wow...That SIS mech takes me back!


 
Posted : 06/08/2017 2:31 pm
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It's a beaut innit. And it works too! In fact all the mechanical bits do, although brakes are... "entertaining"...

It's just the seat rail clamp that's stopping him using it.


 
Posted : 06/08/2017 2:33 pm
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The frame looks very much like a 1995 Marin Bobcat Trail I used to have.


 
Posted : 06/08/2017 2:37 pm
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Is it one of these you need?
https://www.sjscycles.co.uk/seat-posts/passport-standard-saddle-clamp/

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Posted : 06/08/2017 2:51 pm
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Is it one of these you need?

It's a good question, is it what I need?? I've never encountered one of those. If it's the case that we can just switch that part on top of the post then happy days. If you can excuse the appalling state of the clamp here's what's lurking under there currently... #thehorror

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Posted : 06/08/2017 2:58 pm
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Yup - thats what you need. Old skool standard fitment


 
Posted : 06/08/2017 3:00 pm
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Riiiight, well that would be absolutely brilliant many thanks. Is the one in the link likely to be "the right one" or are we going to have to measure something else? £1.99 to fix this would be superb.


 
Posted : 06/08/2017 3:01 pm
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IIRC its a standard fitting - and has quite a lot of adjustability on the bit that clamps the seat post. See how the seatpost you have narrows down? Ols skool lbs might well stock them. 99% sure tho that one will do


 
Posted : 06/08/2017 3:04 pm
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That's great I'm not very old skool I'm afraid so I appreciate your help!


 
Posted : 06/08/2017 3:09 pm
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some advantages to having had my first bicycle 50 years ago!

Youth of today mutter mumble grumble moan


 
Posted : 06/08/2017 3:10 pm
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You probably have the easiest/cheapest option there, but for future reference to measure a post diameter more accurately wrap a piece of paper around it and draw a line across where the wrapped paper meets. Open it out and measure the distance between the marks. Divide by 3.14.


 
Posted : 06/08/2017 3:12 pm
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Youth of today mutter mumble grumble moan

@ 44 y/o I am happy to be referred to as "youth" 😉


 
Posted : 06/08/2017 3:13 pm
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...but for future reference to measure a post diameter more accurately wrap a piece of paper around it and draw a line across where the wrapped paper meets. Open it out and measure the distance between the marks. Divide by 3.14.

As a maths teacher I am very appreciative of your help 😉 😆

TBH I think the limiting factor is not having the bicycle in front of me, not my ability to measure the diameter...


 
Posted : 06/08/2017 3:15 pm
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Well you can get your mate to do that, and maths teacher or not I was assuming that as he hadn't done that it's not something you'd suggested to him (not a criticism at all, it's not an immediately obvious method even to maths teachers - though I wouldn't have bothered telling you to divide by pi if I'd known 😉 ).


 
Posted : 06/08/2017 3:20 pm
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If you knew the extent to which he *hates* anything that could be deemed "maths" then you'd understand why I hadn't pushed him to do that. And if you'd known our maths teacher we had when we were at school together you wouldn't be surprised at his extreme reaction to the subject.

As it happens, I [i]had[/i] suggested doing this (and I'm not just saying that either!) and the idea got the bum's rush and I didn't push it. See above for the reason why 😉

He's coming to visit in a couple of weeks anyway so we are going to resolve it one way or another by then.


 
Posted : 06/08/2017 3:26 pm