Speedo calibration

[Ryanj5049]

anyone aware if i can/need to recalibrate speedo if i fit larger tires????

 

[Jonmc1]

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.

 

[GETGONE]

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.

 

[Jmzvet]

I have 295/70 18s and mine reads 62mph at an actual speed of about 65

 

[clstark7]

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.

 

[Transient]

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.

 

[The Raven]

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.

 

[Ryanj5049]

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

 

[Jonmc1]

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.

 

[Mmill93]

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.

Is this still the case that there's no options for refresh models? I've got a 24 TB, just had a lift and 35s put on. According to GPS speedo I'm running 67 when truck speedo says 60. Also MPG dropped from 26-27 to 17.5, I know that's not accurate but I'd like to know how much the mileage changed in all actuality. I've called 7 shops and keep running into the same brick wall. No help. If course the guys at the shop swore "it won't be much of a difference in speedometer reading..."

 

[Stormin08]

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.

there is a solution for the refresh models, HP Tuners CAN do both ECM / TCM...but it is pricey. if wanting both, it will run right at 3K+

Jeremy Swenson <[email protected]>​ ​	Wed, Apr 10, 9:29 AM
to me

Hi Shawn,

Yes, we can tune your truck. It is more costly and more involved than normal because that is a global b ecm. We need to remove the ECM and TCM and send them to hp tuners for unlock $999.99 and $399.99 plus shipping. Then it also requires 12 credits total which is another $600 before we even begin tuning. The tune cost is $850 for the engine and $250 for the transmission.

Let me know if you're still interested.

Thanks!

Jeremy

 

[Grey]

there is a solution for the refresh models, HP Tuners CAN do both ECM / TCM...but it is pricey. if wanting both, it will run right at 3K+

Jeremy Swenson <[email protected]>​ ​	Wed, Apr 10, 9:29 AM
to me

Hi Shawn,

Yes, we can tune your truck. It is more costly and more involved than normal because that is a global b ecm. We need to remove the ECM and TCM and send them to hp tuners for unlock $999.99 and $399.99 plus shipping. Then it also requires 12 credits total which is another $600 before we even begin tuning. The tune cost is $850 for the engine and $250 for the transmission.

Let me know if you're still interested.

Thanks!

Jeremy

Im a big HP tuners fan. I have the software and use it on my ls1 Camaro. It is sort of wild that it is SO expensive on these trucks. its an apples to oranges comparison though, because I know my Camaro was only 2 credits to tune, and 4 come with the software, so it was basically free. unlocking the ECM and buying all the credits necessary are huge for up front costs, but then you basically have a blank slate to change whatever you feel like. I don't trust myself enough to touch anything on this truck, but in the right hands im sure you could make some noticeable changes in drivability/mileage/performance.

Ive just got the Pulsar on a pre-refresh truck, so this convo isn't relevant to me, but I don't know that I could justify the cost if I didn't have serious plans with the motor to go HP tuners.

 

[Ryanj5049]

anyone aware if i can/need to recalibrate speedo if i fit larger tires????

so comparing to a GPS speedo app i'm still only 1mph off with 34" tires.

 

[The Raven]

so comparing to a GPS speedo app i'm still only 1mph off with 34" tires.

At 27mph, you'll be off by exactly 1mph (so your speedo will read 28mph). At 75 you'll be off by almost 3mph.

When I calibrated mine, it was off by 5mph at 70mph. I have 35's though.

 

[Ryanj5049]

At 27mph, you'll be off by exactly 1mph (so your speedo will read 28mph). At 75 you'll be off by almost 3mph.

When I calibrated mine, it was off by 5mph at 70mph. I have 35's though.

i don't necessarily trust the free app i used () but was still surprised. the (up to) $3K to get recal done properly isn't anything i'm in a rush to do. may try another couple of better speedo app's or wait until i get a ticket.