Mileage ratio for bigger tires

So I got 285/75/16 tires on my truck with my life and I was wondering what the mileage ratio is. I know when you're going 20 on the speedometer you're actually doing like 22, and 65 is actually 69. And I've read that your truck tracks ### on the odometer but to get the real mileage you multiple ### by another number to get the correct ratio.

My question is, what's that number? How many actual miles is 100 miles on my odometer. I've read 1.1, I've read 1.2, I've read 1.17... So what's the actual ratio?

 

There is a tire size calculator on here and it will tell you different speedo readings it might have what your looking for.

 

No I know that, I'm talking about actual mileage, not the speed. I've tried to do it by hand, but it doesn't seem to make sense. I just wanna know how far I've actually gone if my odometer has reach 100 miles

 

It tell you the difference of miles traveled compared to another tire. That should figure it out for you.

 

Use a GPS. Mine is .9

 

Use the tire size calculator as stated above. when you have the numbers take N1 (current tire) / N2(stock tire) to get a ratio which you will multiply your ODO reading by. for instance with my tires (285/70/17) The ratio is 1.07:1 meaning if i multiply the miles on the ODO by 1.17 I get the actual number of miles I have traveled. Orrrr buy an UltraGauge and set it to calculate miles and MPH for you...

 

Every truck will be a little different, they are allowed a +/-5% tolerance from the factory. You will need to calculate it for yourself. Use a GPS to track your actual distance traveled over a long trip or find your true speed for a given value on your speedometer.

 

See this is what I was looking for, you say 1.07. Then you say to get correct you multiply by 1.17, why? Haha

But your tire change is the same as mine so I'll just use 1.17

 

I didn't know that, I must of completely looked over it

 

The true speed I'm not too worried, cause in my town even if I wanted to go over the speed limit, traffic and habit won't let me haha I'm used to driving the speed limit. So if it's a little faster, it works for me!

But I'll use my GPS tracker vs the odometer to see

 

Odometer mileage and speedometer MPH both come from the same source. So your difference will be the same for both.

 

Because I have big fingers and cant type. Sorry for the confusion. Multiply by 1.07 not 1.17.

 

Okay thanks!