March 10, 2011I called to Ford dealer the other day to find out about adjusting my speedo and computer for the 35 x 12.5 tires that I am running. They told me that the Super Duties in 2005 will only adjust up to a 33 inch tire. Is this true is there any way around this and paying 110dollars for the dealer to readjust the speedo?
Forums : Super Duty : Speedo adjustment (785 Views)
March 10, 2011A couple things I have heard people doing is find your actual speed with a GPS, then you`ll just have to kind of remember the difference when driving. I had the same problem as well when trying to get mine adjusted, they said only up to 33`s also. If you buy a tuner, that`ll fix it, plus give you some extra power, plus void your warranty, (possibly). Other than that, not much else I can think of. Hope this helps!
March 10, 2011Thanks yeah I did the GPS think with my phone app and another car. We figured I`m about 4mph off. Thanks for the info is there any programmer you suggest? I have a 6.0 Turbo Desiel.
March 12, 2011persoanally i would not pay the dealer, not only do you have to do it every time you change tire size, you do not have adjustability, so if they do not get it perfect, you have to deal with the error.
There are absolutely companies that make speed correction devices for the F250 + trucks
search in google... you will find them
There is the super lift truspeed and others... you can check google...
"controls for speedometer correction"
March 14, 2011I was looking at a programmers for the truck but someone told me if I get one that isn`t live monitoring that the Ford software just reverts back to the stock tire setting once unplugged from the programmer.
March 14, 2011My problem was on my 03 I could not find a programmer to do the speedometer adjustment, so thats how one of them out there came to be, I made my own.
Anyway I do not know what if any programmers will do what you are saying, you can make an EXCEL sheet and reference to it, or put an inline speedometer adjustment box.
I did hear that on newer trucks the SCT X3 will do the speedometer adjustment for larger tires, I personally have never witnessed it though.
Good luck man
March 14, 2011supposedly auto enginuity will recalibrate the speedo, but i have yet figured out how to do it.
March 14, 2011I have found several that claim to be able to adjust. SCT, HyperTech, and Edge all make a model that adjusts speedos.
March 15, 2011most tuners, such as SCT, only take tire correction into account for tranny shift points, not to correct the speedo. To correct the speedo you need something like the superlift Truspeed device. I believe Hypertech and Superchips tuners can correct the speedo, but the real reason for a tuner is to load custom tunes for additional power and the SCT is the way to go on the 6.0 in regards to tuners and running custom tunes.
March 15, 2011here`s a bunch of calculators that will help:
March 15, 2011The programmer I had claimed to fix the speedometer too, it did not, so I invented my own adjustment device.
As for the speed calculators, they are accurate but you would be better off finding your multiply factor then making an excel spread sheet out of it.
new tire / old tire = multiply factor
now take that number and multiply it by the speed your speedometer reads, thats the corrected speed. That is the logic behind the device I made and works well.