How to adjust speedometer for larger tires?

I went from stock 29s to 31s and now my speedo is dead on. I have gotten 10 speeding tickets and each one was exactly what I was going.

 

I think you may need to slow down a wee bit.

 

Well when I got my truck it came with 245/65/16s and I went up to 265/65/16s and my spedo is now dead on. verified with gps and the speed things the cops put on the side of the road.

 

... I'll slow down 1 MPH just for you!

 

That's a start thanks.

 

http://www.dakotadigital.com/index....tegory_id=287/home_id=59/mode=prod/prd126.htm

I had one of these in my 99 and it worked like a charm

Justin

 

man i really need to get one of these or something b/c i know when my truck tells me in going 71 im really going 65mph. i dont have 35in km2 on my double cab with a 6 inch lift. i need to get one to tell me how many miles i really have

 

I tested my speedometer last night against a GPS and it was perfect. Between the two there was not more than 1 mph difference.

Thanks everyone for your help!

Killer