Seat post diameter

Posted on Sun 2nd, March 2014

• #1

Ribblekid

Hi trying to get an old frame running again.

It's a Sun frame from Birmingham. No other markings than that. I have got a set of calipers to measure the seatpost and I think it's 26mm. Does anyone know what's the correct post diameter to buy.??

I have found a 25.8mm on dreaded eBay but don't want to buy the wrong one.

Caliper is a cheap digital one so may be slightly out

Any help appreciated
• #2

Scilly.Suffolk

I'm happy to be corrected (knowing little about Sun), but I think 26.4mm is more likely: double-butted 531.

If you swing by your LBS they can run a reamer down the tube to clean it out: there'll be all manner of ancient grease down there, which won't help with getting an accurate measurement.

Like as not they'll have some seatposts knocking about, to double-check.
• #3

Ribblekid

Il take it in as I think it's smaller than that it's a 60's frame so don't think it's 531
• #4

Scilly.Suffolk

Worksop badged: post-1963.

Reynolds have been churning 531 out since the Thirties.

Post a reply
- Bold
- Italics
- Link
- Image
- List
- Quote
- code
- Preview
Formatting Help

Don't worry about formatting, just type in the text and we'll take care of making sense of it. We will auto-convert links, and if you put asterisks around words we will make them bold.

Tips:

Create headers by underlining text with ==== or ----

To *italicise* text put one asterisk each side of the word

To **bold** text put two asterisks each side of the word

Embed images by entering:
![](https://www.google.co.uk/images/srpr/logo4w.png)
That's the hard one: exclamation, square brackets and then the URL to the image in brackets.

* Create lists by starting lines with asterisks

1. Create numbered lists by starting lines with a number and a dot

> Quote text by starting lines with >

Mention another user by @username

For syntax highlighting, surround the code block with three backticks:

```
Your code goes here
```
Just like Github, a blank line must precede a code block.

If you upload more than 5 files we will display all attachments as thumbnails.

For a full reference visit the Markdown syntax.