1979-1993 & 94 Conv [Subscribe to Daily Digest] |
Size ~ sidewall height ~ total height ~ rolling circumference ~ rev per mi
-185/65r15 = 4.73"/120.25mm = 24.46"/621.28mm = 76.8"/1950.72mm - 843 rpm
-195/60r15 = 4.61"/117mm = 24.22"/615.19mm = 76.1"/1931.69mm -- 850 rpm
-195/65r15 = 4.99"/126.75mm = 24.98"/634.49mm = 78.4"/1992.30mm - 829 rpm
-205/60r15 = 4.84"/123mm = 24.68"/626.87mm = 77.5"/1968.38mm -- 837 rpm
-205/55r15 = 4.44"/112.75mm = 23.88"/606.55mm = 75.0"/1904.57mm - 859 rpm
-205/50r16 = 4.04"/103mm = 24.08"/611.63mm = 75.6"/1920.52mm -- 853 rpm
-205/55r16 = 4.44"/112.75mm = 24.88"/631.95mm = 78.1"/1984.33mm - 831 rpm
I've posted this before...but stuff gets burried in the archives, so here it is again. Those figures were all from one specific tire from one manufacturer to ensure an apples to apples comparison. I believe the tire I used was a General Altimax HP, with one exception due to unavailibility in one size (prob the 205/55R15 - not much to chose from), where I picked the next closest model. Specs will differ between manufacturers & from tire to tire.
Don't forget that the rolling circumferance will be reduced with wear. As the miles rack up, a 205/60R15 will eventually end up "smaller" & turn more RPM/roll faster than a new 195/60R15. It's all relative. Section width varies greatly between brands & I have personally seen 205's rub lower front spring mounts & rear wheel wells (esp w/cargo). Different cars have different quirks & individual results will vary.
Re speedo error.......ck your speedo & odo against a GPS device, or the measured mile markers on the interstate. Also helpful are the unmanned police radar speed check portables set up near schools...though how accurate those are is up for debate. If your speed reads too fast & miles traveled are too many, you can counter it w/a "bigger" tire. Under reading speedo/odos can be corrected by using a "smaller" tire. Both within reason of course.
posted by 76.118.12...
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