Hi all!
I have 245/75-17 tires on my truck now, and when it's time to replace them, I am thinking of going with 285/70-17's (on the stock 7-lug wheels). That would be swapping a 31.4" tire (OEM) with a 32.8" diameter tire, or 663 vs. 635 rpm's (revs per mile). That's a 4.4% difference. Would I notice? Would anything be negatively affected?
I have heard conflicting information - including:
- that 2011 and 2012 trucks with the EB engine can't change tire sizes at all,
- that I can only change to something that's also an OEM option and the computer needs to be re-programmed
- that it's not an issue at all.

Does anybody know for sure? Even different dealers seem to say different things. Has anybody here done this?

Thanks a lot!

 

toooo many people running wider and taller with no issues. i think people just like to stir the pot so they put out some questionable information. it will just slightly increase the load and that can't have any real impact on a truck.

on the speedo reprogram. i'm running 285's on raptor wheels now and i was told they just programmed it close as they could and i was good to go.

 

You can put them on just fine, and you can go all the way up to a 295/70 tire and have no rubbing issues. My 5.0 lost around 2 mpg when I swapped from the stock tires, and the speedometer is a few mph off. Any dealer can recalibrate your speedo and I believe its around $100. It is not required, but if you want the needle to match your actual speed it needs to be done.

 

Thanks guys!
jtwoodall, which tires did you have OEM, and what did you go to? What was the weight difference per tire? A 2mpg loss sounds pretty steep, I guess it really depends on the tire weight gain.

 

My truck with the stock tires runs 3% slower than the speedo reads. Most stock cars run a little slower. So you will likely be driving 1% faster than the speedo, which is negligible.

Is your truck 4x4? If so, as mentioned, you can go up to a 33" tire. If not, stock is as big as you can go without as leveling kit.

 

Truck is a 4x4, thanks!

 

I went from the OEM Hankook Dynapros from the dealer to a set of 295/70-17 Nitto Terra Grapplers. Definitely heavier but I don't remember by how much.

The 2mpg loss is a rough estimate and that also includes a level and a heavy steel brush guard.

 

Oh. That makes sense now. If I looked that up correctly, then you went from a 41 lbs tire to a 56 lbs tire, that's a 36% increase. I can see the the 2 mpg drop. Thanks a lot for your input.