Al:
Using the Tire Rack Formula (section width in mm/ 25.4= section width in
inches x aspect ratio as a decimal= 1 sidewall height x 2 + diameter of
wheel= rolling diameter in inches
Stock Tire (I've heard different numbers on aspect ratio..including 83)
185/83-15 = 27.08
185/79-15= 26.50
Replacement Tire
205/70-15= 26.29
205/65-15= 25.49
The Tire Rack Old Car Tire Conversion Chart shows Eurometric 185-15 tires
as an aspect ratio of 82- go to this link to see all tires that are a
direct sub for the stock TR6 tires.
http://www.tirerack.com/tires/tiretech/general/size_conversion.htm
Generally, the shorter the side wall, the better the handling as the tire
does not "roll over" as much with a shorter sidewall..however, you also
have to account for section width vs. rim width (ie not having to wide a
tire on too narrow a rim).
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Date: Wed, 28 Nov 2001 17:19:24 -0800
From: "Alan Lindner" <A.Lindner@STRATEDGE.COM>
Subject: Stock tire aspect ratio
Is the original stock tire a 185-80? If the overall height of the tire
should be 26.50", that makes the aspect ratio 79.
I am trying to decide if I want to go with 205-70 or 205-65 and I am
comparing the percentage of speedometer error. I also want very
good handling. No matter what, it will be different than the 225s I
have on now.
William Whitmoyer
69 TR6
90 BMW iX
91 CRX Si
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