Speedometer Calibration with 39's

[derichio02]

Hey Gang,

Has anyone attempted to calibrate/correct the speedometer with 39" tires? I know with the non-Raptor's trying to go beyond 37 and the system doesn't like it and wont update. Has anyone attempted this with the Raptor? I planning on putting my doors back on this weekend to try but wanted to see if anyone else has had success?

@mrandol , @TheBraptor you all have 39's has you attempted this?

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[mrandol]

Hey Gang,

Has anyone attempted to calibrate/correct the speedometer with 39" tires? I know with the non-Raptor's trying to go beyond 37 and the system doesn't like it and wont update. Has anyone attempted this with the Raptor? I planning on putting my doors back on this weekend to try but wanted to see if anyone else has had success?

@mrandol , @TheBraptor you all have 39's has you attempted this?

I have Nitto 38s which are pretty much the same size as a BFG 39 (the bfg run small) and was able to do it with the whipple tuner when I installed the tune. You can’t go any larger then that but you can go there and it would solve your issue. Do you have the whipple tune by chance? It’s my favorite mod so far and I have done a ton of stuff to mine.

 

[derichio02]

I have Nitto 38s which are pretty much the same size as a BFG 39 (the bfg run small) and was able to do it with the whipple tuner when I installed the tune. You can’t go any larger then that but you can go there and it would solve your issue. Do you have the whipple tune by chance? It’s my favorite mod so far and I have done a ton of stuff to mine.

Dont have the tune yet so would have to try via Forscan. I am really thinking about it. Did you do the intercooler too?

 

[mrandol]

Yes, I did the IC as well. You can try Forscan, I have never messed with it before but don’t go above 2890mm or you will throw an abs error.

 

[81wedgewood]

I have the same issue with my 40s. I’ve got past all the modules with forscan except for one! The new Forscan has features for each module to relearn from configuration. The AWD module throws a code immediately that says “tire circumference out of range.” I drove it a little ways down the road and never got an ABS light but the wrench light stayed on and everytime you start it, you’ll get a check 4x4 system/error. I assumed it has to do with the trail turn assist feature and the only way to fix it is to reprogram the AWD module with a new program but I’m not sure how to get that done. Forscan said they couldn’t do it. I’ve looked on other forums for the solution but haven’t found it. Tried fooling it by changing the gear ratio to a higher ratio but that didn’t work because it’s using the tone ring at the hub. I also thought about trying to find a way to add/subtract the number of teeth in the tone ring programming but never found where to do that or if that would even work. I’m not sure if we could physically change the tone with a different one. I haven’t given up, still brain storming.

 

[Turbo yzel]

So perhaps do the max setting at 2890mm
And it will be just a few MPH off ?
I would be ok with that

 

[81wedgewood]

2890 is the magic number for sure. I tried 2891 and after all the relearn only had a code in the pcm. Then I tried 2900 and got a code in all the modules. So the other modules may accept something between 2891-2899 but I didn’t take the time to find that number because no codes is what I’m after. I attached the codes I got when I exceed the magic number.

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