Swapping a bike frame

Gaijin · 31 Mar 2011 at 17:17

Hello chaps,

I'm at the conceptual stage here but wanted to see if there's anything I hadn't taken into consideration.

I have a Kona Four Deluxe FS XC which I got on a great deal. However the caveat was that the frame was slightly too small for me, which is something I accepted at the time, but now I'm a better rider and more confident, I'd like a larger frame.

However, I'd like to retain all my running gear, because I'm a tinkerer and I've upgraded various bits.

Maybe a silly question but, will changing frame size cause drivetrain/suspension components to stop working/working together?

Will it affect the geometry of the bike at all?

The target frame will most likely be a larger Four Deluxe/Supreme frame or maybe a Dawg one depending on whether suspension travel is different, and depending what you guys say.

Thanks.

Jumblejug · 31 Mar 2011 at 17:38

You'd have to check the fork length is supported by the frame. If the forks are too long or short, it could affect how the bike feels. Forks that are too big can cause a frame to weaken. Someone will be able to explain this better.

Chain length may need to be altered, but the other stuff should be alright I think

mistercrabb · 31 Mar 2011 at 17:45

I can't think of a problem, but go on the Kona website and get the geometry specification of the old frame and the potential new frame and compare.

Differences to look out for are:
seat tube diameter (and seat clamp diameter)
chainstay length (if it's longer you may need a new chain)
headset diameter (should be 1.1/8" normally)

You should also be able to see how much travel the fork has somewhere, you want ideally this to be the same as your current fork. (As Jumblebug said, the wrong length can wreck the handling and potentially put more stress on the headtube).

Don't think there's anything else to worry about, but if there is I'm sure someone will point it out..

6thElement · 31 Mar 2011 at 20:08

Gaijin said:
Maybe a silly question but, will changing frame size cause drivetrain/suspension components to stop working/working together?

Depends what frame you swap to. A 135mm rear wheel won't work in a 150mm rear frame, a crankset built for a 73mm BB won't work in an 83mm BB etc. Shifters and rear derailleur should be fine, you might need new housing and cables. Front derailleur might need a different mount. You won't want a 100mm travel fork on a frame built for 160mm and vice-versa.

Will it affect the geometry of the bike at all?

Err you're chaning the frame for a different model and/or different size of course it changes the geo.

Gaijin · 1 Apr 2011 at 10:05

Jumblejug said:
You'd have to check the fork length is supported by the frame. If the forks are too long or short, it could affect how the bike feels. Forks that are too big can cause a frame to weaken. Someone will be able to explain this better.

Chain length may need to be altered, but the other stuff should be alright I think

Thanks mate, thats very helpful.

mistercrabb said:
I can't think of a problem, but go on the Kona website and get the geometry specification of the old frame and the potential new frame and compare.

Differences to look out for are:
seat tube diameter (and seat clamp diameter)
chainstay length (if it's longer you may need a new chain)
headset diameter (should be 1.1/8" normally)

You should also be able to see how much travel the fork has somewhere, you want ideally this to be the same as your current fork. (As Jumblebug said, the wrong length can wreck the handling and potentially put more stress on the headtube).

Don't think there's anything else to worry about, but if there is I'm sure someone will point it out..

Again thanks for your help.

6thElement said:
Err you're chaning the frame for a different model and/or different size of course it changes the geo.

Thanks for your input and advice although I don't really appreciate the sarcasm. I'm asking because I need help on a subject I know relatively little about compared to some people on here - of course I'm going to make mistakes and ask silly questions.

There's currently nothing on the second hand market for my specific model which is a larger frame size at the moment so I'll probably keep an eye on forums etc until something pops up.

Thanks for your help again guys.