Tuner/Big Tires/Speedo
 

Greetings all,

First post for me here. 2007 Duramax 6.6 diesel. I run 37/13.5/17 on my truck and I was screaming past people on the interstate at 65/mph on my speedo. Figured my tires made me a bit faster maybe 10/mph. So, I just put in an Edge Evolution tuner which has the ability to compensate for larger tires. So, I put in my 37's and guess what...it is exactly opposite of what I expected. At 65/mph it show on my tuner that its like 60 maybe. I would have expected just the opposite. Am I missing something? Any suggestions are welcome. BTW, the power is friggn unreal on the extreme setting, go figure....
dk