Silverfish 1987 Mountain Klein

[Silverfish]

Nice Mitutoyo calipers! It's dangerous just measuring from the top of the seatpost as it can get deformed due to the opening/closing of the QR and the slotted top. With telescopic gauges you can drop them in a lot further to get readings lower down to check consistency.

hahaha - thank you - I don't **** around when it comes to tools Altho it does rather sound like I might need to add a bore dial or telescopic gauge to my collection

I know about the flaring on the seat tube - that's why I'm undecided on the 27.2 or 27.4. It's had a smaller diameter post in previously so the top of the seat tube was squeezed in and I've already (gently) prised it apart. Realistically the best thing to try is to find a cheap 27.4 post and see if it fits.

 

[27motorhead]

I'm undecided on the 27.2 or 27.4

As I said before a local friendly bike shop should be able to help. 27.2mm is a more common size and a quick check will let you know if it's OK or not. But as I mentioned before check with a few different ones as they are not always the size they say they are. Mitutoyo's are your friend!

Have you asked other Mountain Klein owners about their seat tube/post size? Like @Swede? And there must be a few Klein forums/threads around you could ask on?

 

[Silverfish]

Ha!
That’s where I started - so far I’ve been given 4 different sizes
I’ll sort it no bother, thanks for your help.

 

[bikeworkshop]

I don't think anyone made a seat tube 27.4 internal.
They are assumed to be stretched open or worn, or just badly made 27.2

 

[Silverfish]

Pretty sure they did and I’m sure I’ve seen a spec sheet listing that
I’ll try to dig it out

 

[Silverfish]

I don't think anyone made a seat tube 27.4 internal.
They are assumed to be stretched open or worn, or just badly made 27.2

Not sure what mag or what year so not quite as helpful as it could be
But spec references 27.4
Also references Shimano XT throughout the review which could suggest 87, but most of the pics show Deerhead so tough to pinpoint it.

 

[bikeworkshop]

Front mech sizes dictated outer tube diameter - 28.6, 31.8, 34.9
These are of course
1" & 1/8
1" & 1/4 and
1" & 3/8
If you wanted to use any other diameter tube, or shape, you fitted a braze on - a rare fit for mtb rings - or a tightening band.
So the wall thickness dictated seatpost diameter.
531 competition tubing taking 27.2, and the stronger stiffer or cheaper seat tubes took 27.0, 26.8 or smaller.

I'd always assumed that 27.2 was an inch fractional size (looks like I'm wrong)- many companies in the late c20th offered 27.2, 27, 26.8, a few offered 26.6, 26.4, 26.2, 26.0, then 25.4 rare (apart from kids bikes) and 25.0 just Peugeot
Above these sizes was a jump to 28.0 and 28.6 for these new fangled materials.

Sheldon has a word to say about it:
https://www.sheldonbrown.com/seatpost-sizes.html
I wonder if klein reamed a 27.2 internal tube to 27.4 to improve the accuracy, but then had to make their own post to fit?
Must be a nightmare if you break your klein post, although that might not be so bad in the US?

 

[27motorhead]

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2332490.m570.l1313&_nkw=27.4+seatpost&_sacat=0AND in the list is this:
https://www.ebay.co.uk/itm/19597959...5NwANocF9LtsxnJPrLPMdlrg==|tkp:Bk9SR6Kmr6KYZA

 

[Silverfish]

Pretty sure a few Klein’s used 27.4, DeKerfs used them as well, I’m sure there were others.
ITM, Dura Ace, Syncros, American Classic, Kalloy and Campy all made 27.4 posts. I don’t remember if IRD, Suntour or Control Tech did.

Memory isn’t as good as it used to be.

The easy cheat of course is to use a 27.2 and shim it with a coke can

 

[27motorhead]

AND sorry to show you this based on the magazine test:
https://www.ebay.co.uk/itm/19579001...bzsiowFOlIuuREXy93mlmXNQ==|tkp:Bk9SR8rgiqSYZA