Speedometer calibration

[mrbullred]

Yes, Rams and Jeeps (DT, JT, JL, etc) will self-calibrate to new tires, but only if you have NAV so that the vehicle is ingesting GPS data. If you don't have NAV, you'll need to do it manually.

Since I already had a Tazer JL, I reused that on my JT, and now I'm reusing it again on the DT. Wonderful tool that does a lot including activating my LED headlights and foglights.

I have a 2020 Ram 1500 with the 12" with navigation. Waited over 1400 miles and it never calibrated itself. I ended up buying the Tazer DT and doing it manually.

Sent from my SM-N976V using Tapatalk

 

[Chrisdp23]

Yes, Rams and Jeeps (DT, JT, JL, etc) will self-calibrate to new tires, but only if you have NAV so that the vehicle is ingesting GPS data. If you don't have NAV, you'll need to do it manually.

Since I already had a Tazer JL, I reused that on my JT, and now I'm reusing it again on the DT. Wonderful tool that does a lot including activating my LED headlights and foglights.

My issue is both read the same speed but the GPS mileage over a travel period of time is higher than the odometer. So how is it that the speeds read the same but the mileage is different?

 

[WXman]

Put 35s on my truck yesterday. Plugged in my Tazer to adjust the speedo and noticed that the factory setting was 32.1" but my factory tires list at 31.9" on Falken's website and the true measurement on the truck was 31.25". How on earth my speedo matched GPS I have no idea...

Maybe these trucks are not like any of the FCA Jeep products.

 

[NewTruckWhoDis]

Yes, Rams and Jeeps (DT, JT, JL, etc) will self-calibrate to new tires, but only if you have NAV so that the vehicle is ingesting GPS data. If you don't have NAV, you'll need to do it manually.

Since I already had a Tazer JL, I reused that on my JT, and now I'm reusing it again on the DT. Wonderful tool that does a lot including activating my LED headlights and foglights.

I installed 35's on mine a few hundred miles ago. I've got the 12" screen and GPS. I'll check today if it auto-calibrated, but I highly doubt it. I'd love to see some source documentation on this claim.

Sent from my SM-N950U using Tapatalk

 

[NewTruckWhoDis]

Confirming that mine did NOT auto-calibrate. I am still off by ~2mph at speeds lower than 40, and around 5 mph for speeds in the 50-75 mph range. Would have been nice.

 

[ehk49]

For those that did have their speedo auto-calibrate, did you have to do anything with the navigation? For example, did you have to plug in an address and actually use the nav? My BH got lifted today and had 35s put on. I did about 20 miles on the highway and another 15 or so on country roads, and so far no joy for me. I'm off by about 6 MPH at highway speeds.

 

[Frambovt]

I have a 2020 Power Wagon, I knew I was going to buy bigger tires so I purchased a hypertech speed calculator ( i had one for my 2013 Power Wagon). Hypertech finally had one for the 2020 2500 6.4L in mid May. So I got it, today I had 35x12.50 duratracs put on, got it home to adjust the speedometer and found out instructions (junction boards) do not match up with the new 2020 2500 rams. It’s the right hypertech product from their website. So I called them and they said I was the second person to call in a day with the same problem. They said they need to get a Power Wagon in to look at it and it could take a few months. I’m kind of disappointed with that. I have the full navigation system and drove roughly 40 miles to see if the speed would auto correct but unfortunately it did not.
Then to top things off my spare will not fit under the bed.

 

[Tex_Ram]

Im about 1500 miles in after lift and 35s and still no auto calibration... I've got the 12", I've used the nav, any other suggestions?

 

[Bearman95]

OK this is what I did. Back in October I put on 33 inch tires on my Laramie sport 4 x 4. According to my Garmin which is not connected to my truck at all, my speedometer was off 2 1/2 to 3 mph over 60. I then downloaded the Waze app on my iPhone and used Apple CarPlay and according to Waze My speedometer was exactly correct. Last week I checked again with my Garmin and again my speedometer was off 2 to 3 mph. I then downloaded on my iPhone another Speedometer app and according to this app my speedometer was off 2 to 3 mph. In other words I was going faster than my speedometer said that I was. So i then completely disconnected my iPhone from my truck, no Bluetooth at all and use the Waze app strictly on my iPhone. The Waze app without the iPhone connected to my truck at all shows that my speedometer is off 2 to 3 mph, again I am going 2 to 3 mph faster than my speedometer says I am. I think if The Waze app is connected to the truck in anyway such as Apple CarPlay that the Waze app uses the navigation unit in my truck as does the Speedometer to determine the correct miles per hour. So I am installing a taser DT to correct the speedometer. I have one in my JL wrangler rubicon and I have never had any problems with the Taser.

 

[Sspearsau]

OK this is what I did. Back in October I put on 33 inch tires on my Laramie sport 4 x 4. According to my Garmin which is not connected to my truck at all, my speedometer was off 2 1/2 to 3 mph over 60. I then downloaded the Waze app on my iPhone and used Apple CarPlay and according to Waze My speedometer was exactly correct. Last week I checked again with my Garmin and again my speedometer was off 2 to 3 mph. I then downloaded on my iPhone another Speedometer app and according to this app my speedometer was off 2 to 3 mph. In other words I was going faster than my speedometer said that I was. So i then completely disconnected my iPhone from my truck, no Bluetooth at all and use the Waze app strictly on my iPhone. The Waze app without the iPhone connected to my truck at all shows that my speedometer is off 2 to 3 mph, again I am going 2 to 3 mph faster than my speedometer says I am. I think if The Waze app is connected to the truck in anyway such as Apple CarPlay that the Waze app uses the navigation unit in my truck as does the Speedometer to determine the correct miles per hour. So I am installing a taser DT to correct the speedometer. I have one in my JL wrangler rubicon and I have never had any problems with the Taser.

This has been my exact experience. I have nav, and it did not auto-calibrate. Only when hardwired in on Waze into the CarPlay does it show I am "calibrated," but as soon as I unplug, I am off 2-3 MPH.

Can anyone that claims to have auto-calibrated confirm their speed is the same as Waze when NOT plugged into the USB for CarPlay?

 

[Ellisstrong]

This has been my exact experience. I have nav, and it did not auto-calibrate. Only when hardwired in on Waze into the CarPlay does it show I am "calibrated," but as soon as I unplug, I am off 2-3 MPH.

Can anyone that claims to have auto-calibrated confirm their speed is the same as Waze when NOT plugged into the USB for CarPlay?

I used a speedometer app as well as waze. I have my rims off right now so I can’t verify

 

[Stryker6040]

Does anyone know with a trinity t2 using the tire size change menu what increments does it go in? does it only save in .25 increments even though you could enter 32.85? will that round up or down to 32.75 or 33"

 

[Stryker6040]

I just read through this whole thread and I can confirm that when using waze through ACP the speedos read the same but when using waze stand alone mine is 2mph off. i dont know if the trucks speed is getting displayed in the car play waze or the actual gps speed is showing in the trucks cluster, but it does not auto calibrate and stay that way unless you run waze through ACP all the time

 

[BGWS]

I have a Hypertext for sale. Model 752504 for 2018+ Ram 1500/2500/3500 $120 shipped

 

[19BlueStreakSport]

Well I just purchased the Rough Country 90019 for when I change my tires in a month or so. Right now I have Nitto RG 35x11.5x20 but that may change to Goodyear Duratrac 35x12.5x20 depending on if my friend buys my stock rims/tires for his GMC Sierra or not.

Anyhow, I got it for a good price $147usd ($200 CDN) plus my local taxes puts me at $179usd ($234 CDN) so I figured while I can get it at the price I’ll jump on it. I have 365 days to return the item from my delivery date so no worries If I don’t need it.

So reading this topic, it has been going back and fourth if the trucks self calibrate or not. Any definitive answer?

Also, the programmer states it corrects the shift points, having 3.21 gears I hear it could search between 7th and 8th gear at about 75mph (120km/hr which is the going speed on the 401 in Ontario). I don’t want it searching and I don’t want to put my truck into 8th gear lock out all the time. Any definitive answer on this as well? Has anyone noticed any shifting point changes and/or 7th/8th gear searching in the highways?

I will keep the package sealed once it arrives to see if my truck recalibrate itself (12” with navigation) and see how the shifting is. If both are ok I’ll return programmer. If the speedo if off after driving for a 1000km then I’ll use it.

I want to have the correct speed, and more importantly I don’t want to add unnecessary MI/KM to my odometer both for warranty and re-sale purposes.

 

[Jeffjad]

Well I just purchased the Rough Country 90019 for when I change my tires in a month or so. Right now I have Nitto RG 35x11.5x20 but that may change to Goodyear Duratrac 35x12.5x20 depending on if my friend buys my stock rims/tires for his GMC Sierra or not.

Anyhow, I got it for a good price $147usd ($200 CDN) plus my local taxes puts me at $179usd ($234 CDN) so I figured while I can get it at the price I’ll jump on it. I have 365 days to return the item from my delivery date so no worries If I don’t need it.

So reading this topic, it has been going back and fourth if the trucks self calibrate or not. Any definitive answer?

Also, the programmer states it corrects the shift points, having 3.21 gears I hear it could search between 7th and 8th gear at about 75mph (120km/hr which is the going speed on the 401 in Ontario). I don’t want it searching and I don’t want to put my truck into 8th gear lock out all the time. Any definitive answer on this as well? Has anyone noticed any shifting point changes and/or 7th/8th gear searching in the highways?

I will keep the package sealed once it arrives to see if my truck recalibrate itself (12” with navigation) and see how the shifting is. If both are ok I’ll return programmer. If the speedo if off after driving for a 1000km then I’ll use it.

I want to have the correct speed, and more importantly I don’t want to add unnecessary MI/KM to my odometer both for warranty and re-sale purposes.

If I recall reading the thread correctly the myth of self calibration has been "busted" and if you are going with a bigger tire this equals less revolutions which actually equals less miles over the life of the vehicle.
My speedo is off by about 4-5mph at 70mph. Doesn't bother me, simple quick math in my head keeps me on speed. I personally haven't noticed any difference in my shift points but I have 3.92.

 

[Bearman95]

After driving about seven or eight months without having my speedo corrected I also thought my shifting was good. That is until I corrected the speedo and now I see just how off the shifting was! I also have the 392 on my 20 Laramie.

 

[Jeffjad]

After driving about seven or eight months without having my speedo corrected I also thought my shifting was good. That is until I corrected the speedo and now I see just how off the shifting was! I also have the 392 on my 20 Laramie.

Did you have the dealer recalibrate or did you do it yourself? Do you feel like it improved your gas mileage?

 

[Bearman95]

I did it with a taser DT. It definitely improve my gas mileage that shows on the truck because before I was going more miles then was actually showing on the odometer. And since the shift points of improved I feel like that it will improve the gas mileage. It doesn’t stay in a single gear as long as it used to.

 

[Jeffjad]

I did it with a taser DT. It definitely improve my gas mileage that shows on the truck because before I was going more miles then was actually showing on the odometer. And since the shift points of improved I feel like that it will improve the gas mileage. It doesn’t stay in a single gear as long as it used to.

Good to know....are you running 35s?