Measured my chainline last night before I transplant bits to another frame.

Zee 1 x 10 cranks, which according to Shimano should have a 50.4mm chainline

However, according to my measurements it was somewhere around 48mm. That was on a 73mm BB shell with one 2.5mm spacer on the drive side.

I’m guessing the difference is coming from the 30T NW chainring. It’s got threaded holes on the chain ring, and a tab around those holes which essentially moves the chain ring in a couple of mm at least

Am I right in thinking that if I ran a 32T ring or bigger, which didn’t have those threaded holes, and the tabs, then I should get back the lost couple of mm on the chainline?

Yup, sounds about right.

The tabs are there to stop the chain fouling on 104BCD spider arms. 32T is the smallest you can go on such spiders without needing them.

I’ve moved back and forth between 30T & 32T without changing anything else and without problem – it’s effectively just under half a chain width.

I’ve moved back and forth between 30T & 32T without changing anything else and without problem – it’s effectively just under half a chain width.

Aye but the new frame has a boost rear end which apparently needs a 53mm chainline so I’m guessing 48mm might be a problem.

Just trying to decide if I can keep the existing cranks and move to 32T or just buy new boost cranks and still run a 30T