How off is my Odometer

So I got my truck lifted and put 285 70 17 on it. Like the title says, about how off is my odometer off? Does the odometer show more miles than actual or less? Thanks in advance.

 

Around 8-10%, your odometer will show less miles.

 

Thanks @Neutral a lot for the quick response man. I'll keep that in mind, I have the mileage from when I got done so I'll just adjust my current mileage.

 

If you have a good GPS unit it's easy to figure it out. Match it up with odometer and see the difference.

 

I came up with 1.075. Set your trip meter drive a tank full then multiply by 1.075 to get actual miles on a tank.

 

7.0% if stock is 265 65 17.

 

Mileage being wrong would drive me nuts

 

My truck is the limited and originally had the 18" wheels with i believe 265/60/18. Im now running 265/75/16. Like OP, how off would my speedo or odo be? How to correct?

 

Thanks for the responses, I was thinking resetting my trip odometer after a full tank would help me figure it out. I didn't want to ask as I figured there is probably already a thread...so again thanks for the responses and not just calling me out for not searching for it. Stock was 265 65 16 so I'll input that into the calculator.

I've seen some calibrators, does anyone have one? Are they worth it? Do they work? How much to install or can you do it yourself?

My main concern is for service but I don't drive that much; is it bad to just do it by month? For instance change the oil every 6mos vs every 5,000 miles? I don't know that much about cars but I'm trying to learn and this forum has helped a lot, so sorry if these are dumb questions.

 

If you are concerned about it purchase the Hypertech speedo recalibrator, it is just plug and play at the back of the gauge cluster and the software is extremely simple to use.