dyls Posted July 22, 2014 Posted July 22, 2014 Ive got a 2008 Kona coil air, which I want to put a dropper post on...Now my problem comes in when Kona decided to use a stupid seatpost diameter (30.0mm), I cant find any dropper posts that are this size, except for the gravity dropper which looks like a 1960's shock and is baie lelik! Is it possible to hone the seat tube out to 30.9mm? That would open the door to a world of opportunities as far as dropper posts go.... What are your guys thoughts? bad idea? good idea? there is plenty meat there to play with and surely 0.9mm shouldn't make a hell of a difference when it is actually only 0.45mm thickness change in the wall of the seat tube.... Any thoughts? ideas? anyone tried this?
Skott5 Posted July 22, 2014 Posted July 22, 2014 Rather get a 27.2 and use shims Capricorn, RockCoach and Bizkit031 3
Guest Smimby Posted July 22, 2014 Posted July 22, 2014 Ive got a 2008 Kona coil air, which I want to put a dropper post on...Now my problem comes in when Kona decided to use a stupid seatpost diameter (30.0mm), I cant find any dropper posts that are this size, except for the gravity dropper which looks like a 1960's shock and is baie lelik! Is it possible to hone the seat tube out to 30.9mm? That would open the door to a world of opportunities as far as dropper posts go.... What are your guys thoughts? bad idea? good idea? there is plenty meat there to play with and surely 0.9mm shouldn't make a hell of a difference when it is actually only 0.45mm thickness change in the wall of the seat tube.... Any thoughts? ideas? anyone tried this? Dont do it, rather get teh 27.2 like Skott5 said
Flowta Posted July 22, 2014 Posted July 22, 2014 Rather get a 27.2 and use shims The options are limited in thisGravity Dropper and/or the copies (ICElift V8, etc.)ThomsonX-fusionThere could be more, but not sure of them right now.
droo Posted July 22, 2014 Posted July 22, 2014 The options are limited in thisGravity Dropper and/or the copies (ICElift V8, etc.)ThomsonX-fusionThere could be more, but not sure of them right now. KS Lev is available in 27.2 as well. Bizkit031 and RockCoach 2
dyls Posted July 22, 2014 Author Posted July 22, 2014 (edited) The options are limited in thisGravity Dropper and/or the copies (ICElift V8, etc.)ThomsonX-fusionThere could be more, but not sure of them right now. Thats the problem, there are loads of 30.9's around, 27.2 are a limited supply, but if honing out is a truly horrible idea I suppose I have no other choice... *edit* The choices on 27.2's seem to be pricey as well, where I can buy 30.9's readily second hand Edited July 22, 2014 by dyls
Flowta Posted July 22, 2014 Posted July 22, 2014 KS Lev is available in 27.2 as well. good to know, now to sort out one for my 27.0mm frame. Can you machine a 0.1mm off a shaft in the fancy lathe of yours? (There's enough meat on the shaft of my ICElift V8)
droo Posted July 22, 2014 Posted July 22, 2014 good to know, now to sort out one for my 27.0mm frame. Can you machine a 0.1mm off a shaft in the fancy lathe of yours? (There's enough meat on the shaft of my ICElift V8) Fancy as in 30 odd years old? Yeah, pretty sure I could make a plan. 0.1mm won't make a massive difference to strength as long as the finish is good.
rudi-h Posted July 22, 2014 Posted July 22, 2014 You say there is meat... what is the wall thickness of the seat tube?
Flowta Posted July 22, 2014 Posted July 22, 2014 You say there is meat... what is the wall thickness of the seat tube? The lower section of the seatpost. Not touching the frame
dyls Posted July 23, 2014 Author Posted July 23, 2014 You say there is meat... what is the wall thickness of the seat tube? here is a pic of the bike, as Flowta said the lower end of the seatpost doesnt go onto the frame, you obviously cant see too much in the pic, Im gonna have to take a vernier home tonight and measure the wall thickness properly but it looks like +/- 2mm thick (they weren't thinking of saving weight when they built this puppy) The OD of the seat tube looks roughly 35mm so that would give a wall thickness of 2.5mm but I have just measured roughly with a steel ruler... not ideal I know...
NixM Posted July 23, 2014 Posted July 23, 2014 Mini hijack: Is it okay to use a shim to go from a 30.9 to 31.6 dropper post in a carbon frame?
AdrianDJ Posted July 23, 2014 Posted July 23, 2014 Mini hijack: Is it okay to use a shim to go from a 30.9 to 31.6 dropper post in a carbon frame?you can use a shim to use a smaller seat post in a larger seat tube - not the other way around
NixM Posted July 23, 2014 Posted July 23, 2014 you can use a shim to use a smaller seat post in a larger seat tube - not the other way around No I am aware that you can't change the laws of physics! I am concerned about having to over tighten the seatpost clamp if a shim is in place.
Flowta Posted August 7, 2014 Posted August 7, 2014 No I am aware that you can't change the laws of physics! I am concerned about having to over tighten the seatpost clamp if a shim is in place. If the shim is machined with the right tolerances you won't have an issue. This is the one you wanthttp://www.use1.com/use-hardware/accessories/309mm-i/d-shims Eddy Gordo 1
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now