Overhead millage difference w/35' tires

[AllGoodHaywood]

Any experience with this? How much should the overhead be off from stock tires? I was seeing 17. 5 - 22 MPG, but with the new tires and Rokktech sensor I am only seeing 14 - 18?

 

[MRosinski]

with 35's my overhead went down to 15 but hand calc went up to 17 from mid 15's. Thats with a corrected spedo.

 

[fozzy]

When I went to 35" tires my speedo was off by eleven percent. The dealer got it down to one percent. Good enuff for me. I used a hand held GPS and charted the speed difference at 30,60 and 90 MPH to get the avarage. The overhead was closer than the truck came stock. By the way, it took the dealer two times to get it that close.