As a general rule, when the big ends go, it pulls the crank out of true and you end up having to take metal off the mains to get it staight again.

Its not uncommon for this to be as much as .5 or .75 even when the big ends are only needing .25, so possibly you will find your mains need to go to 1mm or 1.25mm

1mm mains are available through people like PJ but you might have to wait a while as they probably wont have any in stock.


Only way to know how much of a grind the mains will need to straighten the crank is to do it, which is obvioulsy going to involve spending money just to find out, and then potenitally ending up with it not useable (i wouldnt ever go more than 1mm even if by some mircal you could find the shells for it)