Orange C16R seatpost (+ new (?) removal technique)

[jaypee]

Re: Orange C16R seatpost size (+shim removal)

Thanks again Paddy, looks just like that, at least what I can see. I can see the sense in 'breaking the seal' and I reckon some GT85 will help. I'll let you know how I get on.

I'd like to save it if possible Paul but it's only a shim at the end of the day! I'm more interested in seeing it - it looks original but it certainly doesn't fit - its a bit of a mystery.

It was so tight it caused a just-visible bulge in the seat tube. I didn't think that could be possible but I googled it and sure enough Sheldon covers it.
http://sheldonbrown.com/stuck-seatposts.html

After much thought I came up with a cunning plan. The saddle is held on by a barrel-like fitting.

Near where I work there's a backstreet with some round metal railings.

So I got a mate to help me clamp the top of the seatpost to the railings - him holding the bike in place so as to minimise stress on the tube from the weight of the bike. I took the wheels off but left the forks on which I regretted.

Once it was tight we set about pulling the post out. It took two of us holding the frame about 15 minutes. The screeching sound with every twist - a few milimetres at a time - was enough to bring people out from the nearby pub for a look. By then end we were exhausted and sweating and the last pull sent it into his leg and ripped his jeans.

I didn't imagine it could be so tight and have no idea how it got in there. We were careful to keep it in line with the tube as I was worried about the frame and I think the thick shim must have protected it.

No caustic soda or heat was used and it didn't take a week but I reckon it's a pretty good example of a properly tough seatpost removal! Pulling and twisting the frame with the post effectively fixed to a building must allow for quite a force to pull the post from the frame

 

[paddy311]

I can only guess that the bulging in the seat tube might be caused by oxidisation from dissimilar metals in contact with each other in a steel/ally/steel sandwich. With nowhere to go, the oxide grows and just pushes out the path of least resistance. The seat tube in this case.

When you finally get the shim out I'd recommend giving the seat tube a good degrease inside followed by a thorough going over with scotchbrite before accurately measuring the ID. You may find that you don't need a 29.8 shim...... but something with a bigger OD to take account of the bulge.

Keep us posted (pun intended) :mrgreen:

 

[jaypee]

Fount of all knowledge you are Paddy, pure and shimple! Yes that would explain it all. A relief to find I'm not saddled with a dodgy frame. ;-)

 

[paddy311]

shimply the best :mrgreen:

 

[shinobi]

Thats amazing Jaypee ! i had the same trouble with the post on the Fisher , once it moved i kinda expected it to just come out , but no chance ! it held on till the end ,every screeching mil of it
Cheers Paul.
PS my P7 was 29.6 shimmed to 27.2

 

[jaypee]

Orange must have got a cheap batch of seatposts or something.

So I checked and the bulge is still there - only very slight, not affecting the paint. But then of course the shim is also still there. I'm wondering if actually I'd be better off leaving it there in case the top of the tube might be compromised in removing it. Even if not it's a good reinforcement. I could sand down the post a bit (is that possible? Cromo post) and just use it.

I'd been thinking about just getting a 29.8 post but Paddy's point about the internal tube diameter having possibly increased, together with the reinforcement point makes me think it might be better to leave the shim there.

Any thoughts anyone?

 

[Anthony]

Although the Orange list doesn't say so, the 26.4 post was standard at that time. For 95-97 C16Rs, it says the seat tube had a 30.0 ID and just gives an asterisk for the seat post size, where it should say 26.4 plus shim - and if the shim you have is a 1.7 as you say, then that would make sense, leaving 0.2 to make it fit.

However that doesn't explain why yours is so ridiculously tight, so there must be something wrong. I guess it could just be production tolerances and nothing much to worry about, but I would be inclined to measure the ID of the shim as things stand. Clearly you can't get the 26.4 post back in there, but if you could fit a 26.2 (or a 25.0 plus second shim) then that could solve your problem.

 

[jaypee]

Cheers Anthony, Paddy's idea that it fitted once but became tight due to oxidation makes sense I think. That also explains the mystery of how it got in (even if it were possible why would someone go to all that trouble?)

Re the different sizes etc, that's all well and good but why use a shim anyway, straight from the factory? I've never heard of another manufacturer doing that - I thought shims were just an aftermarket solution to mismatched parts? That's why I thought Orange must have got a deal on a load of posts.

 

[shinobi]

Maybe something to do with the tube sets available to them or being able to use one tube set for different models maybe ? as i say my p7 is shimmed as standard .
cheers Paul.

 

[jaypee]

I guess that could be it Paul. Whatever it is I'm looking forward to riding this one! I was too scared to once I noticed the bulge in case the tube cracked. Not sure it's quite big enough to be a keeper but it'll be fun to find out!

Anyone sanded a cromo frame to make it thinner? Or
achieved the same effect in some other way?