tire size

Hi,
If I put 265x75x16 on my 97 excab,in place of the 245's, they are around an inch taller. Would I really need to get the computer recalibrated?
Thanks,
Bob B

Just the speedometer.

I run 265's in the summer and back to 245's (studded) for winter on my '98 Sub K2500. Difference between the two is about 4 mph. I use a HyperTech tuner to adjust the speedo each time. So if you put the 265's on and don't recalibrate you'll be going about 4 mph faster at highway speeds than the speedo shows.

According to the tire size calculator at http://www.csgnetwork.com/tireinfo4calc.html there is about 1.2" difference in diameter. This accounts for 2.24 mph difference at 60mph. In other words at 57.76 mph with the 265's you will be going 60mph.

I run 265's in the summer and back to 245's (studded) for winter on my '98 Sub K2500. Difference between the two is about 4 mph. I use a HyperTech tuner to adjust the speedo each time. So if you put the 265's on and don't recalibrate you'll be going about 4 mph faster at highway speeds than the speedo shows.
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Great!
Thanks for the answers.
Currently the well worn 245's have me going 3-4 mph faster. so it should equal out.
Thanks,
Bob B