Folding Bikes - Raleigh 20 upgrade -straight chain line ?

Hi,

Having been inspired by many otheres before me, I'm in the process of upgrading my Raleigh Stowaway (same as folding 20) and am looking for some advice regarding parts.

I am keeping the 3 speed SA hub, which has been re-spoked onto an alloy rim. Now the problem is I am going to replace the BB, crank etc but not sure what axle length and crank size to use in order to retain a straight chain line.

For the BB I'm going to use a cheap 24tpi *** or Kinex (http://www.rhizomes.nl/twenty.html).

If anyone can give advice on BB axle length, crank size etc to match up with the existing SA 3 speed hub to achieve a straight chain line it would be much appreciated.

Rgds
tok

I built a SA 5 speed wheel up for my Twenty. Just needed to dish the wheel a bit for it all to line up.

Thanks - but I no longer have the original BB nor crank and am wandering what size BB and what type of crank / chainring others have used to sucessfully aceive a straight chain line with the stock rear SA 3 speed hub.

I didn't re-fit my SA 3 but used a SRAM 7 speed on my Twenty; With that setup I got a straight chainline with a Shimano UN72 bb with a 115 or 117mm axle. It's held in with expensive Phil Wood cups but these are about the only option to hold in a modern BB if you don't want to re-thread the BB shell as a twenty has 24tpi threading not 26 (or the other way round I can never remember!)

The good thing about the above setup is you can adjust the chainline at the BB end of things because the Phil Wood rings have no flange so can be threaded right into the shell on both sides. Therefore you can offset the bb in the shell to some extent to get a good line.

My cranks are 172mm Shimano Tiagras and I fluked a pretty good chainline with that, but with my current fixed setup I had to bolt the chainring on the inner side of the crank arm which is a satisfactory hack to get the line straight, even if it doesn't look quite as elegant.

Hope that's some help.

Have you seen Sammyboy's thread?He seems to have a handle on what works for the Twenty.

Hehehehe - I know some things, but I've yet to tackle the chainline issue. It's bound to give me some laughs, I reckon. I've got a UN72 and Phil Wood cups too, so I can hack it around a bit, but going from an SA 3 speed to a Nexus 7 means a totally different OLN. We'll see how hard it is!