Kooka tech question

[Brass-monkey]

Hi All,

I hope you can help me, I am fitting a Kooka crank to a old marin I'm building, but seem to be having problems. When I screw the crank onto my BB it never gets fully tight and ends up right up against the bb case and the chain stay.

I am currently using a 110mm bottom bracket, should i be using a different spindle size, I have read that bb size is critical with these cranks but can't find any information on what sizes are best.

Cheers

Andy

 

[p3tester]

Hi,

BB spindle length, crank type and frame are all intrinsically linked and important to get a good crank fit but also correct chainline for crisp and effective shifting through the gears.

It very much sounds that at 110mm your spindle is too short for the combination you are choosing.

I'm running Syncros cranks on one of my Marins with a 117mm BB, but having not run Kooka cranks on any bike could not advise on a suitable length to use.

I'm sure someone on here will have run this set up and advise on details

What frame is it that you are fitting onto?

 

[Brass-monkey]

Its a 96 Palisades Trail, when I have been fitting it I get the feeling the spindle is too short or not tapered enough.... :cry:

 

[Brass-monkey]

Is it a case of trial and error? I have the option of 118, 122.5 or 127 spindle length.

This may also sort the front mech indexing issue I'm having too.

 

[My_Teenage_Self]

122.5 seems a common size for older cranks. Are you talking about older Kooka cranks with straight arms, or newer ones with curved arms (low profile)?

 

[Brass-monkey]

It's the curved ones, milled on the front and back, it's the one that had the 3 chainring bolts so you can run the 20t granny ring.

 

[FluffyChicken]

It's the curved ones, milled on the front and back, it's the one that had the 3 chainring bolts so you can run the 20t granny ring.

Got a picture, bit like a Cross between the RaceFace Turbine IB and LP ?

(searches for pic ...)
This http://www.bikepro.com/products/cranks/kooka.html
these ?
http://utahdoglives.blogspot.co.uk/2009 ... -view.html
slightly different.

I believe 122mm but you may get away with 118's

since you have them, try them and measure the chain line.
(values double checked on bikepro by the way)


---
just to add, the newer curved 1997 era ones use 107/133 lengths
http://www.retrobike.co.uk/gallery2/d/1 ... c5a3bc37cb

 

[Brass-monkey]

its the first ones, older style I think.

Second question and excuse my ignorance here, but how do you measure the chain line?

 

[My_Teenage_Self]

On a triple, Centre of seat-tube to centre of middle chainring. Anywhere between 45-50mm is fine.

 

[Brass-monkey]

Cheers for that, I'll let you know how I get on.