Seatpost, 27 to 26.8 ?

[gbb]

80s or maybe 90s Raleigh road frame..original seatpost is 27mm ( SR maybe), but it's tighter than a tight thing B) even after cleaning out the seat tube.

I want a replacement anyway...can i put in a 26.8, or even a 26.4 ?

Any thoughts appreciated.

 

[dan_bo]

a 26.4'll be like a dick in a bucket.

the 26.8'll still slip when very tight........

 

[spandex]

Yes you can. You can get shims if you need them the best thing to do is take your bike into your LBS and ask them to match one up for you. If you cant do that just go into your LBS and ask them can I have a seat post X size but if it dose not fit can I bring it back and swap it for another.

 

[jimboalee]

+1 on Spandex.
Take the frame to your LBS. They will caliper the frame and select a seatpost.

They might not however, accept a seatpost back if it is scratched.

 

[PpPete]

OR get a cheapo 26.8 off ebay (like this maybe) and try it. If it slips, put it back on ebay, and get to work with emery cloth on your 27.0

 

[spandex]

OR get a cheapo 26.8 off ebay (like this maybe) and try it. If it slips, put it back on ebay, and get to work with emery cloth on your 27.0

Or just buy a 1ml shim

 

[gbb]

Ok all, thanks.
I can verynear (vernier) my tube of course, i have several to hand.

I can shim if neccessary, i have plenty of that as well.

26.4 sounds as though it's a no no.

26.8...mmmm i'll keep my eyes peeled.

It sounds as though i ought to keep to 27, so i'll get some emery roll onto a drill and shaft and give the seat tube a good clean.

Muchos obligardos

 

[Proto]

You won't be able to purchase a shim of 0.1mm wall thickness. You could try and make one from a Coke can - it's about 0.1 thick.

Best bet is to go down a size and shim up again. USE make shims for 25.0mm seat posts, OD any size you like.

Alternatively just buy a new 27.0 mm dia seat post. See here:

http://www.dotbike.com/ProductsP463.aspx?A=3&TRACK=DPL

 

[spandex]

You won't be able to purchase a shim of 0.1mm wall thickness. You could try and make one from a Coke can - it's about 0.1 thick.

Best bet is to go down a size and shim up again. USE make shims for 25.0mm seat posts, OD any size you like.

Alternatively just buy a new 27.0 mm dia seat post. See here:

http://www.dotbike.com/ProductsP463.aspx?A=3&TRACK=DPL

Can't you??? It is strange that I have two on the shelf in the workshop! with 20 or so over sizes

 

[Proto]

Very interested to know what brand it is. Certainly USE don't make one that size.

You can get steel shimstock 0.1mm thick, or thinner if you want, sold in strip or flat sheet form. Engineers use such stuff every day. I've got some on my desk right now.

But I maintain you won't get a specific shim designed for seat tube/post/

Think about it. It's .004"/0.1mm thick, about the thickness of a human hair. Very thin. And usually 50mm + long, with a shoulder on the top to stop the shim disappearing down the hole. You can't machine or form it into the shape required.

In one of your previous post you made reference to a 1ml shim. Maybe there's some new liquid type that you pour down the gap. Is that what you meant?

Get a shop to clean out the seatube with a 27.0mm reamer. Clean up the existing seatpost, or buy a new one. My 2p worth.

 

[e-rider]

I agree - you will NOT get a shim 1mm or even from 26.8 to 27.0mm. Old frames always have tight fitting seat posts. The solution is as already mentioned; get the emery cloth in there (this works well usually if it's just paint overspray) or if it's really tight get it reamed to 27.0mm exactly by a decent bike shop and don't forget the grease - job done!

 

[e-rider]

Sorry I mean 0.1mm or 0.2mm not 1mm - silly me!

 

[e-rider]

...and 1ml should read 1mL (this notation changed a few years back!)