<VV> Tire Conversion
Thu, 27 May 2004 21:00:55 -0400
These tire size converters or calculators are pretty cool. This one and
the one Bill Hubble posted. A couple of things to be aware of. They are
figuring the dimensions mathematically. This is great, but remember to
check the actual dimensions of the tires you're looking at in the
manufacturer's literature (or the TireRack web site). They will
probably be a little different.
Secondly, the revs per mile displayed by these converters appears to
assume the tires keep their diameter when loaded and turning. Obviously
this is not true. This is where the "loaded diameter" (twice the loaded
radius) comes in. For instance, this calculator shows a 225/50-16 to be
the correct diameter, 24.9". But it shows the rpm to be 811 revs per
mile. My Goodyear specs shows this tire to have 840 rpm - quite a
difference. What this means is that you can't use these rpm figures for
anything, like trying to get tires that match your Corvair's
speedometer calibration. The calculators are great for diameters and
comparisons, but just forget the rpm figures except for comparisons to
other tires. Since these figures are directly proportional to the
diameters, I'd simply use the diameters for comparisons.
On May 27, 2004, at 4:48 PM, Jim McLott wrote:
> Check out http://www.powerdog.com/tiresize.cgi
> Over the years, I've culled a number of useful web sites from the
> postings of this list, so I'm happy to have the opportunity to share
> this one. I got it a couple of years ago and wish I could remember
> who first poted it so I could give credit where credit is due.
> Jim McLott & Christine, the 1966 Monza convertible she-devil
> Member: CORSA, Corvair Atlanta and Group Red
Bruce W, Schug
CORSA South Carolina
CORSA member since 1981
'67 Monza. "67AC140"