Its not a case of "1mm = 384bhp is safe"

The further its ground the less time it will last irrelevant of the power level.


Depends on how bothered you are about having to pull it apart again, personally i find the engine so easy to pull out of and strip down from my car that i would be quite happy to use 1mm shells or even more, as when it goes i would just sort it out again, but if you are the sort of person who wants to just do it once and not look at it again for 50,000 miles or whatever, then i would say trying to find a good std/std crank was a better option.

The std bearings are cheaper too, by the time you have a grind and undersize shells you are looking at 200 quid+ probably if you go as far as 1mm.

So by the time you offset that against the cost of the standard secondhand crank its starting to look a better option than grinding a crank thats already been ground .5mm before.

Cost varies MASSIVELY i know someone on here who bought a std/std crank for 150 quid recently, but i doubt i will ever get that lucky and i know some traders charge 3 times that much and still manage to get it.