Rough Country Speedometer Calibrator for 19-22 Chevy/GMC 1500/2500HD - 90045
Rough Country Speedometer Calibrator for 19-22 Chevy/GMC 1500/2500HD - 90045
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Rough Country Speedometer Calibrator for 19-22 Chevy/GMC 1500/2500HD - 90045

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Key item features

  • Resets your speedometer to accurate readings for larger tires.
  • Easy Plug and Play connection with Option to return to stock settings
  • Updates OE ECM Shift Points to accommodate larger tires
  • Recalibrates Electronic Stability Control to work with larger tires
  • Backed by Rough Country's Limited Lifetime Replacement Warranty.
  • Resets your speedometer to accurate readings for larger tires.
  • Easy Plug and Play connection with Option to return to stock settings
  • Updates OE ECM Shift Points to accommodate larger tires
  • Recalibrates Electronic Stability Control to work with larger tires
  • Backed by Rough Country's Limited Lifetime Replacement Warranty.
Current price is $259.95
Price when purchased online
  • Free shipping
  • Free 30-day returns

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Arrives by Mon, May 18
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Sold and shipped by Rough Country
4.5825471698113205 stars out of 5, based on 424 seller reviews(4.6)
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Customer ratings & reviews

4.9 out of 5 stars
stars1,276 ratings1,276 reviews
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Reviews summary

Pros

  • : Simple to operate with clear instructions.
  • : Installation takes 10-30 minutes with simple steps.
  • : Shifts at correct rpm and gear ratios.
  • : Allows for simple input of tire size and gear ratio for calibration.
  • : Corrects speedometer reading to match actual speed.
  • : Offers value compared to similar products.
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Showing 1-3 of 1,276 reviews

Jun 18, 2025
Brian H.
5 out of 5 stars review

Seller Verified Purchase

Worked perfectly. Must have for Ram owners with 37” tires

Install was a little more than what I expected not a simple OBD plug in. You have to plug this in behind the gauges and getting there you have to pull a lot of your dash apart. I left in the usb cable and ran it down near the OBD port plug in so if I needed an adjustment I did not have to remove this you will want to as well. I had my son download the software update on his computer and it was straight forward. You can adjust by tire size difference or speedo reading vs GPS mph if you have that info. I did from my radar detector showing that at 70 on my speedometer I was actually going 77. After I put everything back together my gauges did not turn on so I had to take everything back apart and plug in the harness better so make sure you push the harnesses together firmly the first time so you avoid that 2nd dash strip down. After trying I was amazed at how accurate it was at all speeds to the exact MPH. 33 is as on the GPS, 75 is 75 on the GPS ect. This also cured the MPG calculation offset as well as reset the factory shifting points as if you had stock tires. I had been getting some weird shifts in low speed situations when trying to drive slow though like parking lots and this device really smoothed that out. Overall this is a must have and well worth the money. Highly recommended

Review from roughcountry.com
Helpful?29ZLE17ZOA8W859209554
Oct 2, 2025
16ram6. 7.
5 out of 5 stars review

Seller Verified Purchase

Ram 6. 7l 2016 2500 works great!

i paid the extra $20 for fast shipping and got it next day delivered from fed ex. plugged it into my windows computer. installed update, it was easy just fallowed directions that popped up on screen. plugged it into my truck (obd2 port) and fallowed on screen instructions (37/12. 5r18) and it worked GREAT! it change my shift points and truck seems to shift a lot better and my fuel mileage went up a lot to 21mpg (it is d&t). before it would shift to 6th at 55mph and now it shifts to 6th at at 65/70 and that is perfect! my only complaint is; it dose nothing else other than change gear ratios and read codes. it would be nice to dial down my factory rear tire pressure from 80psi. because big tires can't hand big air pressure.

Review from roughcountry.com
Helpful?29ZLE17ZOA8W859209554
Jun 9, 2025
Tiger L.
5 out of 5 stars review

Seller Verified Purchase

Works on 2017 Ram 3500 6. 7 Cummins

Worked great. Simple and easy to use. Had my truck re-geared to 4. 10 with 37” BFG KO2s and this was able to adjust my speedometer accordingly. Be sure your batteries stay above 12. 5v if you have a Ram truck or else ECU damage can occur. Use of a multi meter and battery tender is encouraged while doing any tuning/OBD related tasks on these trucks to make sure voltage doesn't drop below 12. 5v.

Review from roughcountry.com
Helpful?29ZLE17ZOA8W859209554