Originally Posted by mcoine
what does that mean?
If my $6 caliper reads 27.2mm (most of the time) I know I've got a 27.2mm seatpost.
If my $6 caliper reads 120.1mm or 120.2mm I know I've got 120mm dropout spacing.
If my $6 caliper reads 26.5mm or thereabouts I know my crown race is ISO.
The accuracy of my $6 digital caliper is good enough for my bikes.