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On a recent trip in my new purchase-2011 LT 5spd-I noticed a discrepancy between the GPS and the car's speedometer. My 15" wheel equipted Aveo ALWAYS read 2 mi/hr SLOWER than the Garmin. My theroy is that the 15" wheel uses the same calibration as the 14" models. Thus, if one is traveling @ 65 car speed, radar would show 67mph.Someone put your GPS to work in a 14" wheeled Aveo and LMK the results. Thanks!
Wheel size makes absolutely no difference with speedometer. Tire size does. And if the sizing was off it would be more off at higher speeds. I.e. 2mph off at 30 would be 6 mph off at 90
ps my speedo is 2mph high. its just the needle that's off though. my scangauge gives me the same speed as my gps
Thanks to Pickles and Petrified.rabbit for your insights.Before I run my mouth, I will run some numbers to gain a better understanding of wheel size vs speedo readings. I could buy the 14" wheels from the 2007 Aveo in the salvagfe yard here, under "parts" and by manipulating the aspect ratio of the tires, the speedo reading would not change?
correct, the 185/60r14 (stock) versus the 185/55r15 (stock?) are very close.
You are right on....the 185/55-15 compared to the stock 14 came out only 1.2% difference: 887 rev/mile(14"); 876/mile (15") . When I locate an extra wheel and buy premium tires, I will consider an aspect ratio that will yield fewer rev/mile for longer life, better mpgs. Looks like as one increases the aspect ratio, the rev/mile decreases, but what about the handling? Will need to do some research...might go to an a.r. of "65" x 15. Thanks for the calculator and say warm!!