54mm chainline

Any reccomendations? It's for a 73mm shell so my thinking was a UN54 with a 127mm spindle (but I dont think you can get one) on a sugino RD?

Any better suggestions? This is probably one for those of you who know your mtb's... scottnotscot?

an ns bikes coaster singlespeed disc with a bolt on cog on the disc mount. The freewheel should run at 53 chainline but after a few repeated measurements i'm getting the disc side at 54.

yep - measured as always as per Sheldon - any ideas for a crank set/ bb combo then?
What about a good combo for 53mm chainline? I could cope with a mil of chainring spacers...

See I dont know all that MTB stuff as well as I know track bits so I was hoping t'use a track chainset on a longer spindle -

Dou you have any cranksets/bbs kicking about?
You could fit the cranks you intend to use on any crappy old bb then see where that has them sitting and work from there - measure that spindle,measure how much further in/out board you need the chainring to be, double it, add or subtract from current spindle width and hey presto.

nothing in a 73 shell unfortunately - here;s my thinking along those lines though...

a sugion RD needs a 103 JIS spindle for 42mm chainline
so... i need to increase the chainline by 12mm which means increasing the spindle length by 24mm - voila - 127mm spindle... sound sensible?

I think i'll just order them then work from there with spacers etc - i've got both chainring spacers (decrease chainline) and bolt on cog spacers (increase chainline) so we'll see. Are the spindles in a un54 interchangeable?

nothing in a 73 shell unfortunately - here;s my thinking along those lines though...

a sugion RD needs a 103 JIS spindle for 42mm chainline
so... i need to increase the chainline by 12mm which means increasing the spindle length by 24mm - voila - 127mm spindle... sound sensible?

I think i'll just order them then work from there with spacers etc - i've got both chainring spacers (decrease chainline) and bolt on cog spacers (increase chainline) so we'll see. Are the spindles in a un54 interchangeable?

Sounds sensible. Spindles in most modern bottom brackets are not interchangeable. The UN bbs along wth most square taper cartridge types and octalink, isis and powerspline are all sealed units comprising threaded cups, bearings and axle. More modern Ex or X or external bbs are just cups with bearings, the spindle is permanently attached to the (usually) driveside crank arm

Level with the cog on the longest side can do 52mm.

Ps I used it on a mtb frame

aaaargh! so i thought i has it sussed by picking a track crank that needs a 103 jis the putting it on a 73mm shell 127 jis BB (see above) BUT the only 127mm BB I can find is a 68mm shell (un54) - any more suggestions?

Is the outer ring on a MTB normally 53mm chainline?

I have a spare 127mm UN54, athough that would not seem to be too much help to you.

However you are welcome to see if it works.

do you think I could use a 68 shell with 2mm of spacers each side?

Dunno- hence the offer to borrow the one that I have spare and see what happens.

As the axle length is fixed in relation to the drive side cup I would imagine that it would just give you a left hand side crank that was 5mm closer to the bb shell than the drive side, but who knows.

Give it a go I reckon.