Trip mileage difference

So just completed a 500 mile trip in my 2018 4runner. My buddy has a Tacoma. We both run the same lift and tires. We reset our trip odometers at the same time and drove the same route together. At the end, his trip was 26 miles less than mine. Now I never expected them to be exactly the same, but that seems rather excessive. Anyone have ideas?

 

Just talking out of my ass.

But the Tacoma has a little smaller tire from the factory? I'm assuming both tiress are larger than stock now?

Bigger tires will show less miles traveled. Since the difference in tire size is greater in the Tacoma it would show less miles traveled. Looks like its about a 3% tire size difference.

 

Is your speedometer correct?

 

Both tires are the same.
Speedometer is as accurate as it can be with larger tires. Never re-geared as it was only a jump to 285 from 265. Not sure why that would matter if we both start from point A and end at point B and take the exact same route together.
The only thing I can think of is a chip malfunction or an issue with a sensor. Was just curious if anyone else has had an irregularity similar to this.

 

I think the first response by Dillusion is on track.

Both tires may be the same, but the spedo calibration for the two stock vehicles is different because their stock tire diameters are different so your baselines are not in line to start with and the actual variance between the two on the same aftermarket tire is going to produce different results.

 

They both came with 265's as stock. So while there is certainly some slight variation from brand to brand, is that enough to cause that much difference? Not saying you're wrong, I'm just struggling to make sense of it all.

 

^Stock Tacoma tire is 265/70-16 or 265/65-17 (31"). Stock 4Runner tire is 265/70-17 (32").

 

265 is the width. Need to look at all the numbers.

 

Your ass must be pretty smart. This is exactly what I was thinking as well.

^^^this!

265 is the tire's width. The second number is sidewall height, as a percentage of the width. Last number is the rim size.

 

The speedometer is dead nuts on with 285’s. Stock size 265’s make speedometer read 1 mph faster than actual speed hence you accumulate miles quicker on odometer than actually traveled.

I’ve run both tire sizes through speed traps to determine these results.

 

Alright, I'll buy that. So in essence we're both cheating the actual miles lol

 

^The speedo over-reports by 1-2 mph but the odometer does not. Been that way for over 20 years.

 

If what you say is true, that’s a relief. I was bothered thinking that the odometer was overstating mileage. Thanks