Re: [ihc] Formulaic revolutions

["Steven Stegmann" <steve.stegmann@xxxxxxxxxxxxx>]

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