as it say scandal frame 68mm shell, either putting on a pair of lx or deore octalink cranks and need to know the axle length required for

a a standard triple set up

how muh wider to go to run 26 inner and 40 on the middle as a double set up (can' fit them in with clerance using a ht2 chainset)

ta

afaik its the chainset that determines the BB axle length and not the frame. Additionally, that's not going to change for a double or single set up. Since, in theory your middle chainring is going to be the best chainline.

(But I'm open to correction)

On my 456 I tried a 110mm square taper with LX cranks initially- hardly any clearance and chainsuck probs so swapped to a 118 BB and seems ok so far.
From what I can tell you want the longest BB you can find. Only issue could be getting chain onto the big ring but mine works ok.

^^^
Its chainline and not chainsuck that should determine the BB length.
wrong axle length with a BB will give you awful changing and alignment problems.

wrong axle length with a BB will give you awful changing and alignment problems

Really?
It works fine for me, running gears.
I can see the chainline argument for a SS but not with gears.
Why does it matter if your middle ring lines up with middle sprocket when you might never be in that gear?

113 on my 456 works fine, but it does have the little dent in the side.
FWIW I've only had chainsuck probs since i've used ally chainrings! Never had a problem with steel ones. Swopped the middle for a deore LX ally one and its happened a couple of times. Wonder if the softer material is holding the chain when it gets a bit of sh!t on it?

for standard chainline its the crankset that determines the BB axle length.

for what you describe, you would need a longer axle to improve clearance but to the detriment of perfect chainline…….

my lx hollowtech/octalink crankset needed a 121 axle to begin with…..

what im saying is you may not be able to do it with those cranks.

AFAIK it's 122.5 for old LX. Please don't quote me on this though!
You can get 127 if you want to extend it, although you could cheat a little and put an HT2 spacer behind the drive side…