Speedometer Correction 2021 Dually

[Texas Black Betty]

Anyone know how to get speedo corrected on a '21 3500 diesel dually with automatic. I'm running 37" tires. Off 10mph.

 

[healthyrx]

Several options available,
Flash tuners can usually adjust speedo if you have one.
AlfaOBD is another option
JSCAN is what I used on my 1500 with no issues. I
Im sure others will chime in with more options.

Also I gotta request some pics of this rig you have

 

[Quick_Shifter]

Anyone know how to get speedo corrected on a '21 3500 diesel dually with automatic. I'm running 37" tires. Off 10mph.

Depends if its an early or late 21' we've been having issues with calibrations on them. Hypertech isnt out yet, Snap on isnt out yet. There is about an 80% chance it can be done as of today

 

[olyelr]

The tazer ram dosnt work for the new models yet?

 

[olyelr]

Anyone know how to get speedo corrected on a '21 3500 diesel dually with automatic. I'm running 37" tires. Off 10mph.

Fyi, it Is only off by 10mph at a certain speed. Changing tire size makes the speedo off by a percentage, not just a set number of mph. So, while it might be off by 10 mph at say 65 mph, it could be off by 20 mph at 100…or 2 mph at 20 mph.

 

[Rlj2]

Fyi, and no idea if its true. I purchased a pulsar tuner for my 2022 with 5.7, when I adjusted tire size my parking sensors quit working. This was tech supports response
"
We have seen the parking sensors disabled if the vehicle is equipped with the parking assist feature. I’ll do my best to explain, the Pulsar is not really the direct cause of the sensors being disabled after adjusting tire size. It has been seen on our sister companies Flaspaq tuner/Flashcal devices and any calibration device that adjusts tire size even if it’s not our brand. Our engineering team I looking into it but we do not have an ETA as to when a fix would be available if we are able to bypass this. "