Speedometer Calculation
Asked by Roger Nov 03, 2014 at 04:04 PM about the 2011 Chevrolet Silverado 1500 LT Crew Cab 4WD
Question type: General
I had 265/70/18 tires installed on my 2011 Silverado 1500 4wd. I think the speedometer is
off now. Is there an easy DIY solution? Thanks in advance. The factory tires were
265/65/18.
4 Answers
You can use this conversion table to calibrate your speedometer: http://tire-size-conversion.com/speedometer-calibration/ OR you you can reprogram the ECU to make the MPH correct on the gauge with a tool like this: http://www.hypertech-inc.com/products-speedometer-calibrator.aspx
After entering your tire sizes, you're only about 2 mph off (slower) on the MPH gauge than the stock tires. Not much to worry about unless you want to get the speedometer dead accurate. Going from a 70 to a 65 series is not a huge jump so it's not that far off.
When I calculated it from http://tire-size-conversion.com/speedometer- calibration it says + 2 mph not - 2 still not a major difference, but you stated (slower).
Ahhh.. Sorry about that. Yes you are correct. My mistake. Smaller tires = faster speedometer. Thanks for the correction.
