Setting arbitrary tire sizes for speedometer calibration

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lenko
Posts: 169
Joined: Sat Dec 24, 2016 6:40 pm
Vehicle: 2015 Lincoln MKC, 2.0 Ecoboost

Re: Setting arbitrary tire sizes for speedometer calibration

Post by lenko » Tue Jun 04, 2019 10:54 pm

Tried a number of settings in the BCM 726-12-01 xxxx 0862 xxxx and none seem to work. Used the calculator posted elsewhere as well as the hex to decimal/ decimal to hex in the 2015 MKC. There has to be another area to change to get the speedo right. I added a digital speedometer in the centre of the dial one and that digital is right on with Garmin, satellite and other speedo programs on my S7 Galaxy phone. The dial speedo is fast, about 4 mph at 70 mph. I don't want to buy new larger radius tires now just to correct the speedometer.
When I do replace tires then I will go a little bit bigger unless a solution is found here.

snowman
Posts: 1
Joined: Mon Feb 25, 2019 7:47 pm
Vehicle: 2016 F350 6.7 diesel

Re: Setting arbitrary tire sizes for speedometer calibration

Post by snowman » Sun Jun 23, 2019 1:37 am

I found this for my 2016 F350 XLT Dually, in the BCM under 726-45-01 if this will help others.

I have been able to adjust my Speedo using the spread sheet and putting in new tire size. Still trying to fine tune it, but I think I may have to live with it being off 1 MPH one way or the other. :lol:

Thank you OP, for taking the time to put this together.

Edit: I was able to dial in my speedo. On my setup with 255/80R17 BFG KM2. The BCM line 726-45-01 reads xxxx-09AE-xxxx.
Hope this may be helpful to some one in the future.

Randy2015
Posts: 7
Joined: Thu May 17, 2018 10:05 pm
Vehicle: 2015 Ford F250 6.2 flex
Location: Houston Tx

Re: Setting arbitrary tire sizes for speedometer calibration

Post by Randy2015 » Wed Jun 26, 2019 1:06 pm

720-45-01 is where mine is on my 15 F250



j.osbourn80 wrote:
Mon Oct 31, 2016 8:33 pm
I'm trying to recalibrate the speedo on my 2001 f250 superduty for the 35x12.50r17 tires that are on it. PROVING to be difficult to do as I am not certain where to find it or how to do it wi th forscan. Any help would be appreciated.

kmoney25
Posts: 1
Joined: Sun Jun 23, 2019 5:14 pm
Vehicle: 2019 F-250 6.7L

Re: Setting arbitrary tire sizes for speedometer calibration

Post by kmoney25 » Thu Jun 27, 2019 7:41 pm

Guys, I'm running 35X12.5X20 Toyo A/T II on my 2019 F250. I'm trying to dial in my speedometer using the good spreadsheet and line 726-12-01, but I'm still 6mph off. Has anyone had any success with a 17 and up 250 and the same tires I'm using?

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