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Speedometer miscalibrated?
- Thread starter EarthPIG_0311
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I had a big issues with this on my Mini Cooper. I was commuting 190 miles round trip to Spearfish SD to complete my Bachelors Degree. I know exactly how far it is from my door to the campus parking lot. This was based on driving the Subaru outback we had before we traded it for the Countryman and also using maps. The Countryman's tripometer would say it was 212 miles. So a total of 22 miles per trip in extra mileage I was getting hit with. Add that by 3-5 days a week of driving and multiply that by 16 weeks per term. It was adding up quickly. I honestly think they do it by design to shave off miles for warranty claims. When I purchased the proper size tire and put that on the Countryman the miles registered correctly. It also really skews the gas mileage before the tires I was getting around 30-31 mpg and after I was getting 24-25 mpg. So if they can skew the numbers to squeeze out a few more MPG by running like this then they can meet the efficiency guidelines. Some of this loss in mileage was related to the heavy tire I imagine. But when its says you're going father than you are and using the same amount of gas that screws the math up.
Someone should approach Toyota directly about this and see what the options are.
I also do a lot of weekly long distance highway mileage and would prefer to have accuracy from a service and warranty perspective.
I also do a lot of weekly long distance highway mileage and would prefer to have accuracy from a service and warranty perspective.
OP
OP
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Yes definitely should. I'm guessing Toyota Corporation would be the best route? Or any suggestions on who to reach out to in Toyota.
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I just found this thread. I've been wondering the same. My ORP came with the TRD wheels but pretty sure the tires are what I would have gotten with the stock wheels (the spare confirms that). Comparing to Waze or Google Maps, my speed on the dash is always 2 mph higher than the reported GPS speed. I used to own a VW TDI during the emissions scandal so a small part of me wonders if this speed error would artificially boost average mpg figures for the 4R to meet federal requirements. 
I wonder if anyone has explored some real world testing to compare how this affects the odometer as well? My local roads and highways don’t have clear mile markers to confirm if 1 mile really equals 1 mile.I just found this thread. I've been wondering the same. My ORP came with the TRD wheels but pretty sure the tires are what I would have gotten with the stock wheels (the spare confirms that). Comparing to Waze or Google Maps, my speed on the dash is always 2 mph higher than the reported GPS speed. I used to own a VW TDI during the emissions scandal so a small part of me wonders if this speed error would artificially boost average mpg figures for the 4R to meet federal requirements.
There are numerous other threads on this topic. Sounds like manufacturers have to report actual speed or below to avoid over reporting.
On a recent trip to Colorado, my wife got a bogus speeding ticket on the Million Dollar Highway for 24 over. She was going, at most, maybe 5 over. Unfortunately, the Ourey officer was on a mission to issue a ticket and we don’t have a dash cam to back up evidence of not speeding on our end. Made for a rough day since we were on the way to the closest ER after a mountain biking crash high above Silverton.
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All of my Toyota trucks over the years have showed MPH as being 2-3 over what speed I’m actually going. 2025 4R is no exception.
I’ve personally never noticed that, but my only reference points were a 2000 4runner, 2014 4runner and a 2008 Highlander hybrid. GPS accuracy has also drastically improved in recent years and more support for app speed display on iOS, so there’s a chance I just never noticed before.
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The warranty issue is not a factor for me as I will be doing about 7K a year so, I'll hit the three year time limit before 36k. However, I do think Toyota should fix this issue for those on OEM wheels and tires running the recommended air PSI. For those that run non-ohm wheel and larger tires, I feel there should be a service to recalibrate, with a fee of course.
The Rough Country speedo calibrator looks like it's a perfect albeit costly solution. One thing it mentions is shift points for the transmission can be impacted by larger tires. Quote - "Rough Country’s Speedometer Calibration Devices don’t just simply change your in-dash readout, they update your vehicle’s ECM, ensuring accurate shift points and proper electronic stability control."
If I get larger sized tires, I'll probably get the calibration tool too. Shame Carista cannot do this.
The Rough Country speedo calibrator looks like it's a perfect albeit costly solution. One thing it mentions is shift points for the transmission can be impacted by larger tires. Quote - "Rough Country’s Speedometer Calibration Devices don’t just simply change your in-dash readout, they update your vehicle’s ECM, ensuring accurate shift points and proper electronic stability control."
If I get larger sized tires, I'll probably get the calibration tool too. Shame Carista cannot do this.
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When I’m doing 81 mph on the speedometer Waze is showing 78 
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Did you ever get an answer from Toyota? My TRD OR (came with the 33" tire option) does the same thing. I now have 34's and the speedo still shows faster than GPS by 2-3 mph!
If a manufacturer's speedometer is showing even the tiniest bit over the actual speed they are wide open to lawsuits. Mechanical speedometers used to be off by much more and always on the optimistic side. I don't know if all new vehicles calculate speed the same way but if a vehicle uses the wheel speed sensor with teeth on it (I could be wrong but I think all vehicles have these for ABS) then the manufacturer has to include a "conservative" tolerance since there is variation in the parts (tires and toothed wheels) involved with calculating speed.
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though displayed MPH is typically 2 over actual with OEM tires,
the odometer is accurate or even more generous. I've
done painstaking measured mile runs on both my rav4
and this 4runner and odometer is giving me free tenths
every 5 miles. so it seems to be 100% intentional by Toyota
to have a ~2mph offset in displayed MPH.
On both rigs I got bigger diameter tires to get really close to accurate
displayed MPH and (even more free tenths on odometer)
though displayed MPH is typically 2 over actual with OEM tires,
the odometer is accurate or even more generous. I've
done painstaking measured mile runs on both my rav4
and this 4runner and odometer is giving me free tenths
every 5 miles. so it seems to be 100% intentional by Toyota
to have a ~2mph offset in displayed MPH.
On both rigs I got bigger diameter tires to get really close to accurate
displayed MPH and (even more free tenths on odometer)
do measured mile testing,
you'll likely find the odometer is not cheating you.
mph is ~2 off but odometer on my rav4 and 4runner is giving me free tenths
over 5 miles, so no, my 36,000 miles displayed is not occurring at
less than 36,000 miles. I got bigger tires to fix the displayed MPH and
now I get even more 'free tenths ' on odometer
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