Engine RPM at Hiway speed

An inch in tires size is ruffly equal to a 0.14:1 in gear ratio.

2.94 with 24" tires and 3.55 with 29" tires is the same overall ratio.

24" tires is equal to 1:1
26" tires is equal to .92:1
29" tires is equal to .82:1

Just divide 24 by your tires size to get the final ratio.