Help, not sure if I'm being thick

[bpikeuk]

Hi all,

After reading Sheldon Brown too much I have just picked up a Raleigh 20 from the local second hand shop to use as a runabout. I have got my head around most of what I need to do, but, the bottom bracket issue is vexing me :?

I am intending to use a new cotterless axle to take an LX chainset with a single, probably Surly, chainring. I have pretty much calculated my chainline measurement to use with a 3 speed Sturmey Archer rear hub, but, I cant seem to understand how I calculate what axle length to order

Can one of you large brained guys give me some guidance.

Cheers

Barry

 

[legrandefromage]

grab a load of axles and faff until you get the chainline right - I've got loads of 'em

 

[cchris2lou]

the lengh of the axle is dependant off the crankset . check on sheldon web site which lengh you need for your LX chainset . it might have to be modified a bit depending where you put your single ring .

 

[pigman]

and it might have raleigh threads which are now obsolete, so you might have to make sure your replacement axle is compatible with the existing cups & bearings ??

 

[bpikeuk]

and it might have raleigh threads which are now obsolete, so you might have to make sure your replacement axle is compatible with the existing cups & bearings ??

And therin lies my confusion, I know that I need a 5 or 7 series axle to match the Raleigh 26tpi cups, but, I'm
Not sure if that means I can use the axle length that wouls apply to a Shimano cartridge BB.

 

[fatfixie]

The 7 axle will be what you require, which is 5mm longer than the equivalent 3 series due to the extra bb width

Your problem may be getting a 7 series axle short enough- the shortest axle (7A?) may be just right for your LX crank with the ring in the middle position.

I have three twentys myself- planning to use a road crank- if you have a good source of 7 series axles let me know cos i can't get em over here!!

Andy