I am trying to adjust a speedo for larger tires. I tried using the speedo calculator and it didn't seem to work. Is there an issue with the LMM's or am I going about it the wrong way?

Using the calculator for comparing two tires sizes showed a .55% correction. Very small and the truck is only off 2-3 mph to the low side.

I adjusted the revs per mile and I think it narrowed it down from 5 mph off. Is this correct?

Howard