24mm Peugeot Seat Tube

[ScillySuffolk]

I have a 1989 Peugeot Camargue (example here http://flic.kr/s/aHsjumFkqU).

It's a good fit, but I think I could do with the saddle slightly higher; however the post is raised to its maximum and I would like to replace it anyway for one with an integrated seat clamp.

Unfortunately replacing the post is not straightforward as there is a factory fitted shim, reducing the diameter down to 24mm.

24mm seatposts are as rare as hens' teeth and priced accordingly. I was referred to a shop in London that had some new ones made, but they were even more expensive than the second hand ones.

Apart from saving up and holding out for a replacement post the other option would be to remove the shim: it just appears to be held in place by a little brazing.

Before attempting surgery, can anyone tell me why it was shimmed in the first place? It seems unlikely that the tube needed strengthening but I'd like to know for certain.

If anyone has any other suggestions I'd be grateful.

Thanks in advance.

 

[GrumpyOldMan]

Funnily enough, on Saturday I was given a Peugeot Tourmalet. Think it's from 1986 going by the stamp on the hubs. Anyway, I gave it a bit of a once over and removed the seat-tube so I could adjust the saddle. I was shocked to see that not only was it 24mm, which I had never seen before, but it was also made of PLASTIC!!!

Sorry, this doesn't answer your question at all. It just seemed such a coincidence that you should post this just as I had discovered 24mm posts.

Ian.

 

[ScillySuffolk]

...I was shocked to see that not only was it 24mm, which I had never seen before, but it was also made of PLASTIC!!!...

What? the post was plastic? That's plain scary!

I can't think why they would shim down to 24mm, unless they got a really good deal on some 24mm tubes, it just doesn't make any sense.

I'm really tempted to remove it, but for obvious reasons, erring on the side of caution for now...

 

[GrumpyOldMan]

Yes, the post is made of plastic. I suppose it could be fibreglass or something, maybe GRP. It's not a hard plastic, sort of fibrous looking if that makes sense.
When I got the bike I was quite chuffed but the more I look into it the less likely I am to use it. I actually only wanted it for the wheels but when I got it it looked to be in great condition so thought of doing something with it. It'll likely end up being put to the back of the garage like all the others, lol.

Ian.

 

[Old Ned]

Yes, the post is made of plastic. I suppose it could be fibreglass or something, maybe GRP. It's not a hard plastic, sort of fibrous looking if that makes sense.

Carbon fibre??

Unlikely I know :roll:

 

[biggs682]

i also have one that appears to be plastic and as you ride along you can feel the saddle flexing on the mounting area of stem , which takes a bit of getting use to

 

[GrumpyOldMan]

Here you are. Definitely plastic of some sort (or fibreglass) but on closer inspection there is a steel core. It was hard to get a good picture but these should show what I mean.
Interestingly the seat tube is actually narrowed at the top to take the 24mm stem, the rest of the seat tube is probably 26mm ish, I think you can just about make it out in the pic. This is probably different to the frame in the original post which is shimmed although why they would want to is anyones guess. Maybe they had a huge amount to use up and shimming was the cheapest way. Seems a very odd size to go for though.

Ian.

 

[ScillySuffolk]

I decided to swap out the budget Simplex drive train for Campag but only had front derailleurs for a braze-on so measured the tube for an adaptor.

I was surprised to find it was a common-or-garden 28.6mm. I had expected something slimmer and having to pad-out the adaptor.

Looking again at the seat tube I can see that it is as GOM described, with the top 40mm being narrowed to suit the 24mm post.

What I thought was a shim inside the tube, is in fact the tube inside the clamp! Just as well I didn't try and get the shim out: what a plonker.

At the time of writing there is a nice 24mm JP Routens post on eBay which, with two days to go, stands at £25 with eight bidders...