Re: 275 55 20 ? will it fit on stock 20s
My dealer adjusted the speedo as close as possible after installing the A/Ts on the aftermarket Mopar black wheels. It still shows my MPH just a shade below my actual speed. Prior to that, I inquired with a Hypertech dealer, I decided to use their aftermarket speedometer calibrator. Long story, it didn't work and the ABS light remained on even after upgrading the firmware. No issues returning it, but I'll be waiting for SuperChips to release theirs. (they post on this site)
It doesn't void any warranty, but remember that your actual MPH is slightly higher. (mine is approx. 5% off right now +/-) Since I don't have the 430N radio which shows how fast you're going, I usually take a look at those stationary signs that display. (which are probably not the most accurate) It usually places me about 3mph over my speed if I'm going between 55 and 65. Hope this helps.
2011 Jeep Grand Cherokee Overland. Dark Charcoal. 18" black cast aluminum wheels. 275/65/R18 Nitto Terra Grapplers. (replaced the Firestone A/Ts in the pic) Rock rails. Skid plates. Tow hooks. Huskyliners. 44K miles as of 11/13.