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Speedo calibration

Ryanj5049

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anyone aware if i can/need to recalibrate speedo if i fit larger tires????
 
I’m going to recalibrate mine. I went went up to 295/60r20’s with no other modifications. Not sure how far off the speed is, but my shift points are pretty bizarre. At highway speeds it constantly shifts up and down a gear. Truck is a 2019, 5.3, 8 speed.

Original tires were 275/60’s.

On another conversation about tire sizes the moderator advised me to just use a handheld to change the tire size as opposed to spending hundreds on some guy telling me the ecu needs to be completely tuned. I’m going with his advice if I can find enough info on a good handheld. Any suggestions would be appreciated.
 
On the pre-refresh trucks Hypertech and Rough Country sell an inline calibration module. I have it but haven't installed it sine I haven't put my 35's on yet. You hook it to your computer and enter the stock tire size and new tire size and it sends the updated size to the speedo.
 
I have 295/70 18s and mine reads 62mph at an actual speed of about 65
 
anyone aware if i can/need to recalibrate speedo if i fit larger tires????
If you don't adjust, just be aware that you will be going faster than your speedometer says. It will be a very minimal difference at slower speeds, but it could get you in trouble at highway speeds. Pull up Google maps and plug in a destination for navigation. Take it on the highway and it should show your GPS speed. Compare that to what your speedometer says, and remember that difference if you don't want to purchase a device that helps you correct it.
 
I have the Rough Country speedometer calibrator installed in my truck. As somebody said above, plug it into your home computer, install/download software, ever requested data, remove from computer and plug into truck. The whole process took me about 15 minutes. There's enough cable to tuck out of the way.
 
For the 2019-2022 pre-refresh trucks, you want to use the Hypertech/RC module. It's important - not just for the speedo readout, but because the pulse that it adjusts is very important to pretty much every operating function of your powertrain. The transmission won't shift right without it, ABS can be affected, your fuel mileage and trip meters will read incorrectly...all kinds of weirdness.

For the 2022.5-24 refresh trucks, there is no known solution, and may never be. This is a big problem.
 
For the 2019-2022 pre-refresh trucks, you want to use the Hypertech/RC module. It's important - not just for the speedo readout, but because the pulse that it adjusts is very important to pretty much every operating function of your powertrain. The transmission won't shift right without it, ABS can be affected, your fuel mileage and trip meters will read incorrectly...all kinds of weirdness.

For the 2022.5-24 refresh trucks, there is no known solution, and may never be. This is a big problem.
good to know. appreciate the heads up
 
Thanks for the module recommendations guys. I’ll take a look at them and post later on which one I go with as well as the results.
 

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