I have to do the old school way and work the MPH the long way because I don't know any easy equation. So here goes.
Using 7,000 RPM per your original post. RPM = Revolutions Per Minute. That gives us the time to build our hour from. That wasn't for you Owen but for others who may read later.
Tire roll out of 49". I literally wrap a tape measure around my tire.
Final overall ratio, from previous post- 10:1 (I'm just throwing this out there, so don't freak out people, 10 is easier to divide with)
7000/10 = 700 tire rotations in 1 minute
700 x 49" = 34,300" traveled in one minute
34,300" / 12" = 2858.33 feet travelled per minute. Remember 12" in a foot.
2858.33 x 60 (minutes in an hour) = 171,500 feet traveled in an hour
171,500 / 5,280 (feet in a mile) = 32.48 MPH
I hope I did that right.