Now, I know that larger tires set the Speedo off a bit.. howeverm when my truck was on the highway yesterday, my speedo went ALL the way past 85MPH , when I was barely going 70. Now, it's never done this before. When I got off the highway, every time I'd start out from 0, the needle would wave back and forth between 0 and 25, and eventually settle down when it reached a higher speed. Today, it stopped the craziness, and is back to it's old, incorrect self. But, I was wondering if you guys would have any ideas as to what would set it off like that. I only remember the waving incident once before, when I was on the highway from muddin. But it has never went past the 85 MPH mark. Any ideas would be appreciated. http://billybob.coloradok5.com It's all fun 'n games, till someone gets stuck.