1x chainline with inner chainring (64bcd triple)

[ooo]

Do I need to move out chainline if I plan to use inner chainring (64bcd triple) for 1x setup?

as I understand middle ring is 50mm, inner ring should be 45mm or 44mm if chainring is thick
BB shell is 68mm, so with 3 spacers on right side(is it ok?)chainline can be moved out +2.5mm

for example: 28t 64bcd 1x10 with 12-32t cassette - is it ok to use 28x12 ?

[SportingGoods]

I wouldn't do this way.

I would use the middle ring. Then, you can't use 28T chainring anymore. I would bump this up to 30T (or 32T, why not) and bump up the cassette range to 11-36. And leave the spacers in peace so that the cranks land where they should.

[TheRookie]

+1!

[Marin]

I used to run 1x with a 28t ring in the 64 BCD position on a triple, no crank spacers.

IMO this gives you the best chainline, close to the middle of the cassette. I had no issues riding in 28-11, and 28-42 worked really well.

[TheRookie]

On a normal 135 rear it certainly doesn't give the best chainline! Be even worse with the cassette further out on one of the wider rear ends.

[Marin]

On a normal 135 rear it certainly doesn't give the best chainline

Are you sure? The middle of the cassette is about 43mm from the center, Shimano Triple has a 50mm chainline to the middle ring. You do the math.

If you still have a triple, just shift to the small chainring an aim down the chain from a middle gear, repeat with the middle ring.

[TheRookie]

Mines running a 47.5 chainline and the Novatech hub I have puts the cassette near enough 1 gear further out than the Shimano hub I used temporarily (not measured it) , so yes in my case the middle ring location is just about spot on.

[SportingGoods]

From a design stand point, it would not make any sense at all for the small ring of a triple to land in the middle of the cassette. When Shimano designed the triple, the plan was for this middle to cover the middle of the cassette.
So, if your middle ring is NOT aligned with the middle of your cassette your bike is not set up properly.

From a real-life stand point, you need to include the mis-setting of your bike If your cassette or chainrings are offset (for any reason), you need to take that into account. Fix it or use it the way it is.
If you plan to just use your bike as it is set up, then it is as simple as dropping the chain on the small ring and moving the chain all through the cassette. Repeat with middle ring. Pick the one that causes the less stress, the most fluid shifting. No need to calculate or measure anything!

But don't mess with BB spacers. They are not made to shift the chainline but to align the cranks.