Elon;
I hadn't looked at Goodyear data sheets in a while. You're right-- they
are not as comprehensive as they once were-- I wonder why?
Rolling radius will vary as you pointed out but it is a nominal figure
that won't be too far off, at least as a starting point.
Regards, Neil Tucson, AZ
-----Original Message-----
From: 3liter [mailto:saltfever@comcast.net]
Sent: Tuesday, March 30, 2004 3:44 PM
To: Albaugh, Neil; 'land-speed submit'
Subject: Gear Ratio Formula?
Hi Neil:
Well I took your advice and looked at the Goodyear, Michelin, and Toyo
web sites. Toyo was the only one to offer a "loaded radius". Michelin's
site was a waste of time and Goodyear gave almost no circumference, and
if it did, it was all "over the map" with the results. Sometimes the
circumference listed would be smaller (by calculation) that the diameter
and sometimes it would be larger. The point being that no racer would
rely on the inaccuracies listed in the tables. BTW one used to find
Goodyear Bonneville tires under the Vintage/Sport car area. Now, I
couldn't find any reference to Bonneville tires anywhere!
Even if a "loaded radius" was published; due to changes in ballast, CG
shift, and aero loading, the actual race conditions obviously vary from
published data. All I was trying to do was give a tool that would allow
the flexibility to adjust to actual conditions rather than rely on a
diameter that is fairly useless. In any case, the published Toyo "loaded
radius" is always SMALLER than 1/2 the diameter which make the "168"
formula more accurate that the formula with the "336" constant. -Elon
-----Original Message-----
From: Albaugh, Neil, Subject:Gear Ratio Formula?
Elon, et al;
Tire data sheets usually list either the "revolutions per mile" or the
"rolling radius" for a race tire. Either of these figures accounts for
the tire load distortion. (snip. . . )
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