Larger tires, tricks our odometer and…

So I have been thinking, does running larger than equivalent oem tire size trick or give false mpg readings? Does this mean it also provides in accurate odometer readings, since larger tires equal more distance covered?

 

yes

 

This is the case for every vehicle ever, none can measure and adapt to changes in wheel size without reprogramming. Some guys go through the trouble most guys don't, I will be when I upgrade my tires.

 

Yes it does but I don't worry about it. I know the difference and compensate for it. In the old days of mechanical odometers it was a real pain to fix it.

 

Other brands allow you to adjust this in the computer but not Toyota. Gotta get an add on box to trick the tundra

 

So in a sense bigger tires, i will put slightly less miles on my truck!?

Thanks guys for the clarification.

 

Correct. One revolution on stock tires gets you x' down the road. One revolution on larger tires gets you further because of the larger circumference but your computer still only reads what stock tires would have traveled.

 

you can get a hypertech speedometer calibrator. a couple hundred bucks on Amazon. I got one after putting 20s/37s on and it got my speedometer to within 1 or 2mph of accurate speed.

 

Can larger diameter (than stock) tires affect your braking system in any way ?

 

Yes because they're heavier. More weight takes more effort to stop. That said, I have no braking issues after a 7" lift & 37s (might be different for the earlier gen Tundras, but my gen3 is fine. I'm not towing anything though.). That also said, I'm upgrading rotors and pads to heavy duty ones anyway because ...more weight more effort to stop. Plus I'd be much more able to brake effectively if/when hauling/towing.

 

Yes, based on the fact that you’ve got more weight in the tires, greater rotational mass, and increased inertia from that. So the brakes will need to work harder to stop the vehicle.

 

I like the performance so much on my truck it sounds funny! I swear i felt a decline in performance going e rated on 265 tire size!

 

I’ve tested my truck’s speedo (cruise control) against a GPS. My truck is actually 2mpg slower. When I go with slightly larger tires, it should be dead on.

Hopefully will fix the 0.5mph difference against my hand calculation as well.

So check your truck before buying any equipment to “fix it”.

 

Good copy!

 

Speed is easy with any instantaneous GPS app, but getting an accurate MPG will be a little trickier as the distance recorded by the truck is wrong too.
I think you'll have to GPS a route to get a known, fairly long distance, drive it as straight as possible, and then gas up and see how much you used. And likely you'll have to do this several times and get an average if you really want a pretty accurate reading.

 

This is pretty useful.
https://www.tacomaworld.com/tirecalc?tires=245-75r16-255-70r16