math help !!!!!!!!!!! ?

C

CR500AF

New Member
i plan to buy one of these engines and use it for a razor scooter

anyways i wanted to gear it to go about 30mph at 8000rpm with a 4'' tire

I was hoping i would not have to gear it at all and just run the tire

how fast would a 4'' tire spinning at 8000 rpm be going ?

any thoughts would be helpfull
 
if your using a friction drive, you would need a 1.25'' roller. if you want to chain it, you would need 9-28t with a #35 chain or #25
 
(4" * pie) * 8000 revolutions per minute = 100480 inches of travel per minute = 8323.3 feet per minute * 60 minutes = 499398 feet per hour divided by the number of feet in a mile (5280) = 94.6 MPH.

Good luck and God bless.
 
He said "I was hoping i would not have to gear it at all and just run the tire " so I assumed he just wanted to make the drive shaft his axel.
 
i have done fricton drive with a 5.5hp rc engine on a razor scooter but i was eating tire ever 30-40mins so it will have to be chain drive or the wheel will have to be mounted to the engine and 90mph would be be cool but deadly
 
I want to build a scooter that can fit in my locker and do 30mph and ve more power then brains

its makes 8hp with no pipe but with a pipe it sould be a 10-11 hp 15lbs scooter
 
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