<PRE><B>Question 1159089</B>
55 mi/hr is 80.6667 ft/sec 
C=pi*d
if the diameter is 23.70 inches (2 rubber parts and the wheel), then the circumference of the tire is 74.45 inches or 6.205 feet
That would make 13.00 rev/sec for 55 mph or 60/55 *13=14.18 rev/sec at 60 mph

5.25 inch tires have a diameter of 25.5 inches and a circumference of 80.11 inches or 6.676 feet
At 14.18 rev/sec, one is now going 94.678  ft/sec or 64.55 mph or 65 mph rounded

3.6 inch tires now have a diameter 22.2 inches or 69.74 inches circumference or 5.812 feet
13 rev/sec for 55  mph or 5.909 rev/sec for 25 mph
with these new tires, 5.812*5.909 is 34.34 ft/sec or 23.42 mph
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