z415

Hey, I was working on my roommate's older steel Campagnolo (1980s maybe?) and the old Kalloy seapost (which was cut too short for him) was clearly marked 27.2 and was very loose to the point that tightening the bolt all the way still wasn't tight enough since it slowly slid down even after we wiped off all the grease.

He then got a cheap black, used seatpost marked 27.2 and it was way too big - as in a hammer was needed. It was one of those "grooved" ones that was gritty feeling that I usually think of for mtbs so we ended up getting another one, a Kalloy Uno, that was 27.2, but that was way too big also. It takes both of us and a lot of 3-in-1 oil to get it to the right position.

I was just wondering why three different seatposts of the "same" size would be all that different. Do alloy/steel cylinders shrink over time? I didn't think the really loose one we pulled off was that old. Also, are there any options to get one that would work - maybe something a little smaller? We were thinking about that, but didn't want one that was as loose as the original one that was supposed to be 27.2.

cs1

First, what kind of bike is it? Second, of course it won't fit now because the seat tube is messed up with the first seatpost.

I had a similar problem with an older Waterford. It came with a 27.2 seatpost in a 27.4 dia seattube. The lug looked similar to what you described. I had to take it to a frame maker to have him resize it back to the proper dia. Now a 27.4 fits perfect like it should. If the bike is Klein, Waterford or Raliegh with 753 tubing then it probably is a 27.4 seatpost. Let us know.


Tim

unworthy1

This was a recent topic on the CR list, and as usual I didn't study it very carefully, but the jist I took away was that there are a LOT of bikes (not just the 753 frames) with 27.2 seatposts in them that really would be happier to have a 27.4. If you notice any crimping or deforming of the ears on your seatlug's clamp, and you care, best to take your bike to a good, experienced shop or builder and have the tube reamed for the larger size. I bet there will be a bump in the demand for 27.4 posts, now, so stock up.
Also, when you do get the tube and post sorted out, use grease, not 3-in1 oil.

vpiuva

"It" being way too big - the above posters seem to think you mean the ST and need a larger 27.4 post. I'm reading that you mean the post and you really need a 27.0. What could have happened with the original post is that someone sanded it down. I've done this - took a 27.0 down to a 26.8 on a bike where I didn't want to spend any more $ and had a 27.0 post in the bin that I didn't want to use on a better frame, so I made it work. And never use a hammer. I'm glad you got it out. Calipers are your friend, measure twice.

z415

Sorry folks... I meant Bianchi... it was late last night and I was up watching my school win their Final Four game... anyways, its an older Bianchi steel road bike.

vpiuva - you hit the nail on the head - that is exactly what I meant. So I am guessing a 27.0 would work? There is no damage to the frame or the threading, etc.

At first I thought the original owner sanded the post down like you do, but the "27.2" stamp was still so well defined I couldn't imagine how he/she did that. Thanks though. Oh, and we learned to not use a "hammer" (it was actually a rubber mallet) the hard way: we slapped the saddle on and pounded away. It was one of those newer fancy, but relatively cheap, carbon saddles, and it broke.

Thanks people, sorry for the misinformation in the post.

vpiuva

You may want to check before using a 27.0, it may work, but Bianchi also used some 26.6 and 26.8's. You might find it here: https://sheldonbrown.com/seatpost-sizes.html

(edit: link fixed)

z415

The link is bad, but I believe I have seen that page you are referring to. The problem is that we don't know the exact year or model of the Bianchi. Actually we have a pretty good used bike shop here in town and the owner would probably just let us stick random posts of different sizes in to see which would fit best.

Thanks a bunch.