[Farmall] MPH per thousand revs

[Jim Becker]

There can be quite a bit of variation in circumference between tires that 
are supposedly the same size, especially so for older style bias ply tires. 
You will probably get a better number by direct measurement rather than 
calculating it.

Check your tire pressures.  Put a chalk mark on the tire and another on the 
ground at the same point.  Roll the truck one revolutin of the tire and put 
another chalk mark on the ground in line with the one on the tire.  Measure 
the distance between the two marks on the ground.  Going several revolutons 
and measuring the whole distance will improve the accuracy some more.

Jim Becker        jim.becker at verizon.net

----- Original Message ----- 
From: "Howard R Pletcher" <n9ads at juno.com>
To: <farmall at lists.antique-tractor.com>
Sent: Friday, October 22, 2004 11:20 PM
Subject: Re: [Farmall] MPH per thousand revs


> The circumference of the tire in feet will be
> 2 x Pi (3.14) x R/12.  The Tire Revs/Mile will be 5280/Circumference.