As you’re doing a single n/w up front (presumably on a triple crankset) and a single cog in the back (presumably a Shimano HG freehub), I’d say that you have a nice bit of wriggle room for getting the chainline set perfectly.
Just find the matching BB for the M751 triple and not worry about it.
(Uh, make sure you match the BB width to the BB shell on that frame, obviously).
As you’re doing a single n/w up front (presumably on a triple crankset) and a single cog in the back (presumably a Shimano HG freehub), I’d say that you have a nice bit of wriggle room for getting the chainline set perfectly.
Just find the matching BB for the M751 triple and not worry about it.
(Uh, make sure you match the BB width to the BB shell on that frame, obviously).