How to Measure a Lock Nut
No vernier caliper? No Problem a ruler will do the job.
If you measured at 50mm the size is 50 divided by 5, this gives us an 10 sized lock nut , 30mm would give us an 6 sized lock nut (30/5=6).
To measure a lock nut simply measure it's bore and then divide the measurement by 5.
eg: 50mm divided by 5 = 10 so the size is a 10 sized nut eg: MB10, KMFE 10 etc