0.2mm is it a big difference?

[Pyro Tim]

I bought a seatpost advertised as a 27.0, but when I dropped it into the frame, I thought it was a little small. I've had the calipers on it, and it's 26.8mm. I can get the frame to bind on it, but...


... how wise is it to run it? Or should I offer it back up for sale, and continue my grael search?

 

[Barneyballbags]

Re: 0.2mm is it a dig difference?

I've got a 27.0 sat here, and I need a 26.8 for my Zaskar.....

 

[Pyro Tim]

The seat post in question, is titanium

 

[bhill22]

Re: 0.2mm is it a dig difference?

Too risky get the correct size

Why - risk damaging the frame and if it collapses maybe your crown jewels

 

[Barneyballbags]

The seat post in question, is titanium

Well mine, um, isn't .. It's just a Kona Racelight Tahoma post. However if you just want something to use until your holy grail comes along then it's yours for the price of postage. It's no use to me in the shed

I MIGHT even be interested in buying your post, so keep me in mind if you decide to part ways with it.

 

[Rampage]

So, a diameter difference of 0.63mm.
Personally I wouldn't risk it on a frame I like.
Someone will mention coke can in a minute.

 

[Spudly]

I would say that it should be fine, my 98 caldera had a 27.0 post as its standard fitment,which is nice and snug, however, the Thomson Elite seat post that i recently won and fitted went in fine (albeit a little more snug) and i hadnt actually realised that i had found more than one on the bay, bidded on the one that was a 27.0 (whilst in drink) and forgotten about doing so, a day or so later the other one came up for ending, i bidded, won and paid.

It turned up and i fitted it, all nice and happy then i got a notification that i had won the first one, and after paying and it arriving i realised the one fitted currently is a 27.2, and the second one was indeed the correct 27.0!

Both fit fine, and the smaller size was the original one fitted, so i would say its such a marginal difference it probably only means one half a turn more on the allen bolt to secure the post!

 

[Pyro Tim]

thanks mate, I do have a nice X-lite post I was using, but the ti looks so much nicer.

That Kona post might look good on the wife's Hahanna though.

I've thought of the coke can shim, but think it will be too thick. The difference is literally the thickness of a sheet of paper, all the way round. I had the calipers on a sheet too

 

[mattr]

Only problem with undersized posts is they are only supported at the binder, and have plenty of room to wiggle in the seat tube. Which isn't good.
At least a post that is nominally the right size will have significantly less wiggle room.

 

[Pyro Tim]

I know, and I have it a long way out too, only about 80-100mm in the frame. It's my WCF so carbon bonded to steel. Steel at the binder, but still carbon there too. My favourite bike, and I'd be lost if I broke her