Bought it cause I put 35's on my Tundra and I was about 5mph off comparing to GPS. Also noticed shift points were off along with gas mileage. This calibrator not only allows you to fine tune the speedometer but it also brings the shift points back to factory settings. I am now back to 18+mpg on highway and 13-14 aound town and I am heavy on the right foot. Easy install, just make sure to zip tie to prevent rattles behind the dash. Highly recommend.
2015 Toyota Tundra 5.7L
Awesome product!!! Great step by step instructions. Had 0 problems with the installation, it took about 45 minutes from start to finish. I would recommend you measure your tire to get the exact size. I upgraded to a 22in wheel with 35s and programmed 35s first and it was still off 2 MPH. Once I measured and saw that it was really a 34, I programmed that in and it was perfect. Much smoother shifting too. I also noticed a 2mpg gain too!!! This is a must if you have a lift Tundra with 35s or larger