Re: [ihc] Formulaic revolutions

["Ed Sohm" <idaemes@xxxxxxxxxx>]

It just seems counterintuitive to squirm/slip 3.3 % and not tear tires up in
very short order.

Ed

----- Original Message ----- 
From: "Steven Stegmann" <steve.stegmann@domain.elided>
To: "J Grammer" <jim@domain.elided>; <ihc@domain.elided>
Sent: Monday, September 15, 2003 7:22 AM
Subject: Re: [ihc] Formulaic revolutions


> I also noted that they claim to get revs/mile by the multiplying a
constant
> times the tire diameter.  Hmmmmm
>
> Steve
> ----- Original Message -----
> From: "J Grammer" <jim@domain.elided>
> To: <ihc@domain.elided>
> Sent: Sunday, September 14, 2003 6:34 PM
> Subject: [ihc] Formulaic revolutions
>
>
> > >Ed,
> > >
> > >I found my notes from talking to Goodyear.
> > >
> > >I'd asked them about a LT235/85R16 truck tire.  They told me 657 rev/mi
> > >which works out to an effective  diameter of 30.71 inches.  If you take
> the
> > >std formula for figuring the diameter of a tire you get 31.73 inches.
> > >
> > >The section width of this tire is 235 mm.  235/25.4 = 9.25 inches.
> > >Height of the tire section is 9.25 * 0.85 = 7.86 inches.
> > >
> > >The dia is (7.86 * 2) + 16 = 31.73 inches
> > >
> > >That's about a 3.3% difference.
> > >
> > >Steve
> >
> > That's 'cause rev's/mile is based on the static loaded radius of the
tire,
> > not the 'free' dimension as measured. An 8-10 ply 235/85 doesn't give up
> as
> > much dia. as a flotation size(typically at 'normal' pressures). As
noted,
> > rim width also affects SLR.
> >
> > Jim