I just put new tires on my car that have about 1" bigger diameter than stock. I used a tire calc and it said I am about 4 mph off. Any way I can adjust this so it's more accurate? Can I take it into a shop and how much would it cost. Thanks.

 

Nope no adjustments.
the digital to analog converter has no adjustment.

 

So i'm stuck with my speedo being off?

 

pretty much, just have to be aware that it is off, and 4mph? seems like alot, according to the radar things that the police put up say I am 3mph off, and I have 18s on mine.

 

It doesn't matter what diameter wheels you're using, the tire's rolling diameter can still be off. What tire is listed on the door jamb sticker and what size tires do you have on? Give us the XXX/XXRXX format

 

The tires are almost an inch and a half bigger in diameter. They barely don't rub. I don't have to numbers now and I don't feel like getting dressed and going outside on Thanksgiving.

I believe the stocks were: 185/70/14

And the new ones are: 205/65/15

 

You can fix the speedo by installing an Apexi Rev & Speed meter. Might be a bit more expensive than you'd like, but you can adjust your speedo in % with it.