Speedometer off?

In my TRD OR MT, I noticed that the analog speedometer was reading about 67 MPH while the digital one was 70 MPH. Anyone has similar off reading? Also, my truck has all original tires and wheels.

 

They are all like that.

 

When I had my FJ, the analog speedometer and GPS were reading exactly the same throughout the range. In Tacoma OR with GPS, is the digital speedometer fed from satellite?

 

Nope. Mine is off 7-8% with my tires

 

When I compared with my real GPS the digital readout is closest to being correct. Odometer is short by 2.5%.

 

Posted this in the 0-60 thread but it belongs here too

Going to court on a ticket and I just had my speedo calibrated to provide documentation for the judge, according to this certifying agent, my speedometer is off from a calibrated dyno and my tire size was only increased one size up from stock. 265/75 instead of the OEM 265/70.

This is a copy of the results, signed copy is with the lawyer for submission.



Even with the tire upsize, according to the tire size calculator, it should only decrease indicated speed by less than 2mph at 65. Speedo certifying agent says he typically sees Tacoma speedometers reading about 3-4 mph too slow which is about what we see here on the dyno when you account for the tire change.

According to him, manufacture tolerance is about +/- 5% so 3 mph at 60 is about right. Needle reading may also be affected due to parallax.

 

I have stock sized tires and my speedo readout is 2 mph slower after 55 than actual speed.

 

On my 2012 my speedometer was off as well, when I upgraded my tires to one size bigger it was dead on accurate.

 

It looks like digital reads GPS as it matches my handheld GPS.

 

Wasn't that Hillarys excuse? Ignorance still makes it illegal.

 

Keep your politics to yourself.... never plead "not guilty" to any infraction, just used it to reduce an automatic wreckless driving charge (+20 mph over) to a simple speeding ticket (less than 19 over) and to show your speedo even with the right sized tires can be wrong.

 

so you changed the tire size but it's toyota's fault? You do realize that every tire brand is different in actual size even though they are the "same". BFGs run notoriously small and some other brand run large.

 

Never said it was Toyota's fault, I'm saying the speedo can be inaccurate up to 5% from from the factory and a tire change can amplify it worse than the tire calculator indicates.

Not running BFG either, running a less aggressive tread.

 

problem with the calculator is it assumes are tires are the exact same size. in the real world they aren't. BFG 35's are known to run around 33" tall

 

But my point in all of this and the topic of this thread is the speedo may be in error from the factory based on what the dyno guy has seen and confirmed by my dyno run.

 

you didn't measure the speedo on factory equipped tires though.

 

I still have the OEM tires so I can measure the diameter of both sets, the TGs that were run on the dyno measure actual 31 inches, the OEM measure actual 30.5 so using some math for circumference does not equate to a five mile difference in speed at 70mph.


Are you done arguing yet?

 

go have the test done and I'll stop arguing

 

No need, math proves my point.

 

Not really. Like I said, tires aren't the same. One brands 265/75 could be an inch off of another brands