Ti seat tube size question...

[Applesauce]

I have a Lynskey-built Kona Raijin for my next mountain bike. I'm thinking seriously of putting a dropper post on it, and would like my options to be as broad as possible. It has a 27.2 seatpost diameter out of the box, with an aluminum shim pressed into a 34.9 mm seat tube that seems to have ~1.4 mm walls.

Anyone have any thoughts on reaming the shim out to 30.9? I guess that this would leave .3-.5 mm walls on the aluminum shim. This should be more than enough to accommodate the weld deformations, no?

I remember when I worked at a Ti framebuilder a while ago, we pressed an aluminum shim past the weld deformations, and then reamed out the shim to 27.2. I assume this was because we a) could not find seat tubes with the appropriate combination of ODs and wall thicknesses and/or b) reaming past the back sides of the welds at the seat cluster would compromise the integrity of the frame.

Out of curiosity, can any one confirm the logic here? But in the interest of utility, can anyone also make any suggestions for how I should approach my Raijin?

ps. Before anyone says it, I'm not worried about the warranty on the frame.

[steve garro]

KS makes a dropper in 27.2 many say is the best.
- Garro.

[Applesauce]

KS makes a dropper in 27.2 many say is the best.
- Garro.

I found out about that today. It's a solid option, apparently. I'm no longer hip to what garners what press: I ignore most cycling this-and-that, despite spending all day, every day in front of bicycles. But the KS looks good... Waiting for Canadian availability, of course!

[randonneur]

the KS' are pretty much the best cable-actuated posts going, I think. I will caveat that by saying that it definitely seems as though that dropper post technology in general needs to mature a bit. Pretty sure calgary cycle can get 'em, so your shop should be able to as well...

[Willie1]

KS is definitely the way to go. You can order them from Superstar Components in the UK if the distributors don't have them..

[Jayme]

I'll agree with what everyone else said since I have no experience with dropper posts. Just thought we should have a response from every Alberta based VSalonista .

Jayme

[Applesauce]

OK, ok, I get it. I'll go for the KS before reaming the frame. I can get them - but not the 27.2 post, which is a new model, and hasn't arrived at any Canadian distributors yet. So it's unlikely that CC has them, either!

[Willie1]

Superstar Components - High Spec Parts For Peanuts

In stock.

[Applesauce]

Canada will have it mid-January, by the looks of it. I won't be doing any hot descents before then - at least, not sans skis.

[randonneur]

No kidding, this winter's come in like a lion.

At any rate, good to know. might be able to stick it on a hard tail project i'm dreaming up for spring...