Re-jigging my cyclocross bike and realised I am totally blinkered with MTB tech. So after a bit of swotting up I got a white industries free wheel and I’ll have the back wheel re-built onto an open-pro rim – sorted (I think/hope).

At the other end I’ve got on order a Token JIS square taper 116mm hub but not sure what cranks I could pair this with – struggling to find anything decent that’s not silly monies, would an old shimano square taper FC-m730 be a good shout or a middleburn or something else? – what about the chainline – how do I know that’s going to work…?

Now I’m wondering if I should just switch to hollowtech, you can get more bang for yer buck on cranks there, square taper seems dead, but that could have chainline implication too, could it? I’m not sure what that would do to the crank positioning.

Was hoping to pair the cranks to a surly 38T chain ring.

Spa Cycles TD-2 or XD-2 for a pony, rings for an extra Pavarotti. More bang for your buck than a box of Poundland fireworks.

http://www.spacycles.co.uk/m2b0s109p0/Parts-and-Accessories/Components-Gears-Chainsets

what rear end spacing?

after a bit of swotting up I got a white industries free wheel and I’ll have the back wheel re-built onto an open-pro rim – sorted (I think/hope).

So you decided against doing it on a budget then? 😆

I’ve had a couple of DayOne’s. Square taper BB’s last for ever, I’d stick with them for that reason.

There’s nothing wrong with square taper cranks – DuraAce track cranks are still square taper plus you’re guaranteed a BB that lasts more than 6 months. Find a crank you like and then source a BB to give you the right chainline – it’s easier that way. Just repurposed an old CX frame to run SS with a lovely Token freewheel – gurning my way around the local MTB routes

Find a crank you like and then source a BB to give you the right chainline – it’s easier that way

This – you need to use axle length to tune the chainline.

@bez – nice! and a black option too – I like it

@thomthumb the rear hub is 135mm

@tthew haha – aye. It always ends up that way once I get invested in upgrades

@dovebiker & @wwaswas – looks like I’ve gone the Irish route then.

Guess I’ll get the cranks and then hope the BB is correct, no doubt I’ll be back on here in a week or two trying to figure out how to gauge chainline correctness – thanks for the heads up though, I’d have probably just fitted it thinking a like for like swap is what was required.

I’ve got old Shimano LX M570 with a 104mm spider on my cross bike running 1x to keep me on trend 😉

Spa cycles various own brand cranks are good VFM, or you can pay a bit more for a stronglight logo…
Spa will sort you out for chainrings too ir you can go to ‘Velo-solo’ for some overt nicheness.

Shop about for some Middleburn if you absolutely have to make sure everyone knows you’re minted, but TBH you don’t need to spend a fortune or resort to HT2, as there’s loads of good square taper options…

FWIW, I’ve always found chains designed for geared systems are less fussy about precise chainline than dedicated singlespeed chains are (and they’re a bit lighter, too).

White ind recommend a 3/32 chain and they are generally better than 1-1/8 singlespeed chains anyway. The freewheels are great though, and SS cross is great fun.

rear chain line is 47.5 then.

this matches up with mtb middle ring. road outer is 46mm (so close enough imo although a 1mm spacer would help)

cranks need to be spaced with the correct BB to give you the correct chainline.

be cautious spacing chainline with BB as not all square tapers are equal. IE 116 may not be 110 + 3 each side.

Find a crank you like and then source a BB to give you the right chainline – it’s easier that way.

+1

EDIT: kmc z610/ z510 are the best SS chains by miles.

I’m building a SS CX bike too.

Using a DMR kit though so my rear spacing will be a lot easier (I hope), never measured chainline before!?

Using a DMR kit though so my rear spacing will be a lot easier (I hope), never measured chainline before!?

That is the easier option (I even use a splined hub on fixed (Halo FixG) so I can get the chainline right regardless of cranks (plus the cog can’t slip)

I just measure chainline by eye – look down the chain from cog and you can see if it is veering left or right. You can also hear it.

Anyone know of any on-line guides on how to measure hub/BB shell/crank offset etc. and work out the correct BB to get the chainline right? It’s a definite gap in my knowledge.

I just measure chainline by eye – look down the chain from cog and you can see if it is veering left or right. You can also hear it.

easier to see if the pedals are turning. You need a friend to do that for you while you look from the back wheel, or an OAP gribber-grabber.

easier to see if the pedals are turning. You need a friend to do that for you while you look from the back wheel, or an OAP gribber-grabber.

turn the wheel bacwkwards?

Anyone know of any on-line guides on how to measure hub/BB shell/crank offset etc. and work out the correct BB to get the chainline right? It’s a definite gap in my knowledge.

i don’t think you can.

It’s down to the crank manufacturer. They will tell you the right BB to get specified chainline.

Adjusting for non standard chainline becomes a game of suck and see/ measuring due to the non centring issue of BBs that i mentioned up there ^.

Generally speaking a set of square taper cranks will be designed for a single BB spindle length to give 47.5mm chainline, or for two lengths (eg 113/118mm) to give 47.5mm or 50mm chainline. In the case of a triple the chainline refers to the middle ring; for a double it’s a virtual chainline at the midpoint between the rings.

So the easiest thing is normally to look up the spec for the cranks, working from one of those chainlines as appropriate. (In case it’s not obvious, note that every mm of chainline adjustment requires 2mm in the spindle.) Often a good starting point is Sheldon’s list:
https://www.sheldonbrown.com/bbsize.html