Re: [ihc] Tire RPM @ 70 mph

["Jim or Ginger Aos" <jaos@xxxxxxxxxxxxxxxxx>]

----- Original Message ----- 
From: "James Lidberg" <jameslidberg@domain.elided>
To: "Joel M Brodsky" <jmbrodsky@domain.elided>; <ihc@domain.elided>
Sent: Monday, March 15, 2004 10:41 PM
Subject: Re: [ihc] Tire RPM @ 70 mph


> Joel,
>
> Thanks for your calculation.
>
> Is this calculation for the wheel RPM?
>
> The little rollers inside the wheel bearings are rotating much faster
aren't they?
>
> Like 10X to 30X wheel RPM?
>
> Depending upon their diameter and race's diameter?

The RPM on it outside is the same as the inside.  The difference is the
surface speed at the circumference.  A 20" diameter tire has to make more
revolutions to cover 10' than a 30" diameter tire.  But the hub of the wheel
turns the same noumer of times as the outside of the tire in a given
distance. Cheers Jim A.
>
> - Jim in Mesa
>
> > Jim,
> > just some rough numbers...
> > 70 mph ~ 103 ft/sec
> > 31" tire is  pi*D or 8.1 feet in circumference
> >
> > 103/8.1 = 12 rev/sec
> >
> > or 720 rev/min.
> >
> > I think you're okay.
> >
> > JoelB
> >
> >
>
>
> **************
> Jim In Mesa - James Lidberg
> jameslidberg@domain.elided
> '79 Scout II/4X4/345/Edelbrock 1400/727/D20/3.07 open/PS/PB/4"Trailmaster
> Copyright 2004 All rights reserved