NEW SHOES SPEEDO QUESTION

[jbod77]

2019 limited, etorque, air suspension. So I put on a set of Nitto G2's in 285/55r22. Tire calculator says my speedo should be about 5mph off @ +/- 60mph. When using a GPS speedo on my phone it's spot on with the dash. Checked a couple of "you are going this fast" signs and everything matches. What gives?

PART 2
And if my searching proves correct, the dealer cant do a flash to tell the truck I've got bigger tires and I have buy a calibrator?

 

[Rob5589]

The Rough Country calibrator will do the trick

 

[jbod77]

The Rough Country calibrator will do the trick

What's it going to do if the Speedometer isn't off?

 

[Rob5589]

What's it going to do if the Speedometer isn't off?

In regards to his part 2

 

[spinxt]

Measure the actual tire. Just because a calculator tells you what the size should be, doesn’t mean that’s what it actually is. Mine was off almost 1-1/4” from calculator to actual.

 

[spinxt]

That said, I think the calculator you’re using is the problem. The difference between 275/55/20 (stock) and 285/55/20 is negligible and would result in less than a 1mph variance at 70mph.

Not worth the expense of buying a programmer

 

[jbod77]

That said, I think the calculator you’re using is the problem. The difference between 275/55/20 (stock) and 285/55/20 is negligible and would result in less than a 1mph variance at 70mph.

Not worth the expense of buying a programmer

285/45/r22 is stock on my truck. 285/55r22 should be 2" taller. That said, I'll hit them with a tape measure when i get out of work....

 

[spinxt]

285/45/r22 is stock on my truck. 285/55r22 should be 2" taller. That said, I'll hit them with a tape measure when i get out of work....

My bad...didn’t notice the 22”

 

[Raminit]

I just did the 285/55R22 Ridge Grapplers and I’m scratching my head also. I was looking at the Waze - Apple Carplay and it matches the speedo. I was definitely expecting there to be a couple mile difference. I always thought Waze-ACP was satellite based speedo, what gives?

 

[jbod77]

I just did the 285/55R22 Ridge Grapplers and I’m scratching my head also. I was looking at the Waze - Apple Carplay and it matches the speedo. I was definitely expecting there to be a couple mile difference. I always thought Waze-ACP was satellite based speedo, what gives?

I downloaded a free GPS Speedo from the appstore just in case there was some sourcery tying carplay/unconnect GPS's to the speedo. Run the Speedo app alone and not plugged in to a usb port just to try and validate my findings. I 've posted in some 5thgen groups on facebook and didn't get any insight there either.

 

[Bearman95]

I put 275/60/20 on my Laramie sport and the speedo is off 2 mph at 75. That’s according to my Garmin GPS which shows 2 miles Per hour more than The speedometer. Does not bother me one little bit! Transmission shifts as it always did!

 

[saturn298]

2019 limited, etorque, air suspension. So I put on a set of Nitto G2's in 285/55r22. Tire calculator says my speedo should be about 5mph off @ +/- 60mph. When using a GPS speedo on my phone it's spot on with the dash. Checked a couple of "you are going this fast" signs and everything matches. What gives?

PART 2
And if my searching proves correct, the dealer cant do a flash to tell the truck I've got bigger tires and I have buy a calibrator?

You can get alphaobd and a Bluetooth obd scanner and change it cheaper and do many other things, vs getting a speedo calibrator from RC or anyone else.