Currently I have a 08 with the stock 17" wheels/tires. I'm upgrading to 18" wheels with some beefier Nittos or BFGs. When I get all of this done, will I need to have my speedo recalibrated?

 

If you get larger tires, then yes. You can do 2 things? Take it to the dealer and have them do it or buy a tuner and you can do it yourself as well as enjoy tunes on your truck.

 

Tuner it is!

 

... or you can save a little and get THIS

 

Yeah I saw that. I might consider that, but then again I know in the end I'm going to get a tune for the truck, so I might as well save some extra money and spend it on a XCal2 or 3

 

that actually depends on how big you go. when I put 33's on my truck. I thought I needed to recalibrate my spedo. I asked the dealer to change it for me. they said they checked it to gps and it was not off far enough to make a change. I was confirmed this by checking manually on the speedo check markers on the side of the highway. by my calculations it was off like arround 1 to 1.5 mph and 60 mph. then a year ago I got a gps that confirmed my spedo was off by only .75 mph or so at 60 mph. so I figured the spedo came from the factory off and I fixed it by putting the bigger tires on. although I am now going with 34's so I will either just figure out how far I am off with the gps and live with it or pay someone to recalibrate it or I am still looking at an edge programmer. which would be able to change it. I just wish the prices had not gone up from the prices they were a few years ago when I first considered getting one.