Speed accuracy

So, it appears my speedometer is not accurate - maybe. On my second truck as well.

I have Waze running most of the time so I can see where others have reported speed traps, etc. It also shows you how fast you are going and what the speed limit should be. When I first start driving and my speedometer shows 80, Waze is showing 85-87 in my Tundra. I shrugged it off and presumed the GPS information was just 'off' a little. The more i drove the more I noticed it is always off when first driving but eventually begins to match up - after 15-20 miles. Every time.

This is occurring in my Capstone I bought last week. It also occurred in my Limited I traded in on the Capstone. Both are 2023 Hybrid 4x4's.

Saying all of that, I use Waze in my other vehicle and it does NOT show that much of a discrepancy.

Now I am wondering if my speedometer is off or if the Tundra is making the GPS signal report inaccurate data. I would like to think it is the GPS' issue and not the truck, but I am not sure.

Anyone else done an accuracy test on their truck or put their phone driven Speedometer next to the truck reporting one?

 

Have you added larger tires to your truck? My speedometer is off 5-7 mph at 60+ mph, but I have 35” tires installed. Adding larger tires throws off your speed.

 

Should have specified. Both trucks are completely factory.

 

GPS apps are more accurate then the speed indicators on any vehicle. example, to display the current speed, some cars measure the actual speed, then multiply this value by a defined speed factor and add between 2 and 4 kph (1-2 mph). This should eventually cause an industry-accepted accuracy of 10% for the displayed speed reading, which in theory means that the difference at city cruising speeds shouldn’t be higher than 8 or 9 kph (4-5 mph).

 

I have this same issue happening in my truck. It happened with stock tires and now also 33" (only ~1% larger). The speed is always off by 5-7 MPH vs. waze. I don't know which number to trust. It's a little frustrating to know that the odometer and MPG calcs may also be affected. In the end, doesn't matter a ton unless I get ticketed for going 88 in a 75...

 

Drive next to someone you know, on speakerphone, with a vehicle which matches GPS speed. If the problem's on the truck side, it's likely that the discrepancy gets worse the faster you go (typical for speed inferencing from a pulsed signal), so do this on the interstate to see the biggest differential.

 

Ive noticed on my truck, that the truck's speedo is saying im going 2-3 mph faster than gps. I just figured it was more Toyota shenanigans to say gas mileage is better than it really is

 

This is your GPS issue if the GPS speed and speedometer converge after driving some distance.

Usually the car’s speedometer is higher than actual speed and the difference in speed is larger at higher speeds vs lower speeds. Pretty much all manufacturers are like this because tires don’t stay the same diameter from new. As the tire wears down it gets smaller and the actual speed will decrease vs what the speedometer shows. If you were to install a larger tire, your actual speed will be the same or higher than the speedometer.

 

Question to OP-Paul

People are still having trouble finding one truck and you are on your 2nd 2023? How did you make that happen? Did you get a good trade-in value for your 1st one?

Earl

 

Per law, since your speedometer can’t legally be higher than your actual speed. Almost every manufacturer has it 2mph slower than the actual speed of travel

 

When the cops put up one of those speed sign trailers my truck is always matched right to it, FWIW.

 

IIRC OE is allowed a 5% tolerance, usually quicker than slower

Do a true mile for mile, not a truck to GPS test.

 

I settled for the first one and didn't get the level I wanted. I then just got lucky on the second one even though it is a level higher than I wanted to spend. 23's are all around central Texas. You just can't be tooooo picky. I wanted a 1794 as I had one before but no 4x4's so I went with a Capstone 4x4. Trade was not bad at all, I lost very little.

 

Thanks for all of the replies.

 

My 20 actually has the correct speed now with 33” tires. I have checked and verified with a gps.

 

My 22 platinum showed 2-3% too high on the Speedo when stock

 

Agree with this. I traded in an Audi for my Tundra. My A6 and wife’s Q7 were both 4 mph fast at highway speeds. The Tundra Speedo is pretty accurate. I’ve used GPS to get an idea about how far off and then keep in mind when driving. Also, it seemed to be a percentage so at 15 mph it may be dead on, while 75 may be 3-4 mph off etc.

 

Those seem to be the worst indicator of speed and if you blow through them fast enough they don't even light up...

 

I find it funny that they are always higher. It’s never lower. Wonder how big of an impact this is on mileage? Because technically you reach your warranty mileage faster.

 

My truck on 35’s only shows 2-3 mph difference be Speedo at 80mph (legal speed limit in Idaho)

 

I changed out my tires to the BFG KO2 in 275/70/18 and the speedo is an exact match to GPS.

 

So, many of you are saying it is usually higher. Mine is lower, like 6-7 MPH lower than my GPS is saying. That is ticket territory, especially if I am speeding above what I think I am going by 5.

 

Reread my post and determine which device has the error - phone or vehicle. If the truck is at fault, something is throwing your CAN message off. Since the speed 'magically' gets corrected after some time, I'm wondering if the hybrid controller isn't at play.

 

Hello,

I just bought a ‘23 Platinum Tundra Hybrid and am having the same issue with Waze (using Apple CarPlay). I took my truck in today to get a couple of things taken care of and they put me in a ‘23 Highlander. Same issue with Waze there. Sometimes it shows the same speed as the vehicle but most of the time it shows 5 to 7 mph higher on Waze. My previous vehicle did not have this issue and I believe I know why. In my previous vehicle I didn’t have “wireless” Apple CarPlay and the speed was always accurate. I believe the issue might be the “wireless” part of using Apple CarPlay. Once I get my truck back, I am going to remove my iPhone 14 Pro and reinstall via USB-C cable to see if this fixes the issue.

Anyone else have similar issues?

 

Scratch that…just tried it out in the Highlander and it is still off by 5 to 7 mph. Must be on Toyota. Hopefully they will send out an update to correct. I am assuming the speedometer on the vehicle is correct and the audio system is casing the error. Seems odd that Waze…being GPS driven for the speed…could be affected by the audio system but it must be!

 

My speedometer is closer to accurate with 33s than the 32.4s it came with. Radar still has me 1mph slower than indicated at 70 mph.

 

Come out here and I’ll aim a radar at you. If you’re off by quite a bit, I’ll write you a ticket voucher to go get it fixed and then pay court fees to have it dropped. Easy.

 

typically toyota speedo are 1.6 kmh off (1 mph lower) from the factory across all models.

 

Mine matches the stand alone speed stations as well and I have 33" tires on mine.

 

I had Waze show a different speed than my speedo the other day. Restarted Waze, no dice.

Then I restarted my phone, started Waze, and the speeds matched to within 1mph.