Anyone else that has adjusted there tire size have there speedo off? I had it set at 31's in the tuner and my speedo was off by like 3-5 mph so i moved it down to 30.5 and its still off by 2-3 mph. I'm gonna put it down to 29.75 because that should add about 2ish mph to it and see how that works. I know gps units aren't always the most accurate but its dead on if i take the tune of with the gps so i think its pretty accurate. Just curious if anyone else has had a similar problem.

 

If you compare my door sticker to what I have now, there's aboiut a 1-1.5" difference or so in height.

Had my dad follow me with cruise at 55. his truck (all stock) registered 54 or so. So no difference on my end.

 

yeah when i set my speedo up, said i was going 3 mph then i really was at 75. i turned it back down, idc

 

hmm did you change your tire size in the superchips? it started when my dad took it to the mountains and he never speeds usually like 5 over maybe and he said he was cruisin with it at 60 in a 55 and was getting his doors blown off and then there is a sign that tells you your speed on 322/22 right before 15 and he said it was registering 45 when he was going like 49-50ish...i'm gonna change it when i get gas before i head home today to 29.75 i think you can go in quarters and see how it acts then hook up the gps when i get home and see what it says my door jam's say 235/75r15's stock and i have 31x10.50's on it so i set it to 31...idk though i'll have to figure something out lol my girlfriend always followed me home last year and she always said that when i told her my cruise was at 60 she had to back off because when her's was at 60 she would ride up my ***

 

yeah, i forgot to mention it was with the superchips