MPG Tire Size Comparison

I'm looking for some new tires. I'm getting 33" tires but I haven't decided on 10.5 or 12.5. Right now I have 31x10.5 and average about 19 on the highway, 17 City. So those with oversize tires, what size do you have and what's your MPG?

 

You're likely to see anywhere from a 2-10 MPG drop. lol

C-rated pizza cutters and re-gearing are by far your best bet to maintain as much MPG as you can. I'm not aware of a 255/85r16 tire in a C though, at least a good tire. But the E rated 255's are still lighter than a comparable 285/295.

 

Haha that's quite the margin. I might just have to accept the fact my MPG will go down drastically, which I can live with. I'll shop around but it seems like some K02's would be the best option for a decent on and offroad performance.

 

The other thing to consider is: do you find your self loosing traction or needing taller tires so you don't scrape bumpers or belly pans?

31's can get you in to, and out of, some pretty hairy situations. A lot of people just feel they "need" 33's because that's what everyone else has.

If MPGs are your main concern, I'd take a hard look at if you really need them. As with anything, it will be a compromise. My truck isn't a daily driver, and I haven't actually tracked my MPGs (even when it was a daily driver) for nearly a decade, lol, so for me MPGs aren't a factor. I'm going with 255 KM3s for performance reasons.

 

I have been in some situations where I really wish I had a larger tire. There are lots of washed out roads around me and I always find myself in the ruts (thank God for the e locker) where a bigger tire may reach the bottom or be able to claw out easier.

 

ahh, cool, makes perfect sense.

Have you thought about if you want a mud terrain vs an all terrain?

 

Don't forget you need to factor in the mileage difference between running stock tires and 33s since your odometer will be off...your MPGs will probably look to be worse than they really are if you're just going by the numbers your trip odo is showing

 

I think tread design makes a bit of difference as well. MT's will always give you worse MPG's then AT and street tires (but who actually runs those???). I'll have to pay attention to what my mileage does on my new cooper AT3 295's. Going from 255 Toyo MT's on Steelies to the Cooper's on F5's I lost about 12lbs per tire... BUT I'll have more rolling mass making contact with the road... my guess Is I'll see about the same MPGS

 

Hmm haven't thought much about that. Some mud terrains are a little too much but there are a few (like the BFG KM3 and Grabber X3) that I love.

 

Good advice! I knew my speedo would be off but never gave much thought to it affecting mileage too.

 

I've never bothered to actually calculate but I've read somewhere on here that it's roughly a 7% difference with 33s

 

I avg 20.1mpg on 285's. Manual trans w/ 4.56s. I once saw 23mpg with stock 225/70r16s when my truck was still a prerunner automatic

 

Man that's good...I'm lucky to get 15mpg city/highway. Added weight and supercharger doesn't help. I'm also on the stock 4.10 gears

 

Gears make a huge difference. My old truck was 3.4 auto 4x4 w/4.10s. Once I added 285s I was 15-16mpg, once i regeared to 4.88s i was close to 18mpg

 

Okay so my original tire (according to my sticker) was 225 = 28.3". That means it had a circumference of 91.1" or 7.58'. That means that for every mile driven the tire would revolve 695.7 times (5280/7.59). A 33" tire revolves 611.8 times per mile. 695.7/611.8 = 1.14. So there is a 14% difference. That means when your speedo reads 60 mph you're actually going 68.4 mph. So just multiply your speed or mileage by 1.14 and you'll know exactly how fast/far you are going

Side note: This is a great way to keep mileage off our trucks haha.

 

yeah it's kind of funny how you don't hear much talk about odometers being off due to larger tires when people are buying/selling 1st gens. Not that it makes a huge difference for most but for some higher mileage ones it might

 

One of those good for the seller bad for the buyer scenarios; especially so when you consider how much harder the truck worked it's whole life to push the bigger tires.

 

I went with 265/75 KO2's in an E rating, and I'm not seeing a change in mileage really. I live in a small-ish town and not far from work, so most of my driving is slower (45 mph or less) and sitting still at lights that take forever to change. I think I went from 15.6 to 15.9 -- so actually BETTER mileage with a (slightly) larger, heavier tire. And surprise -- it seems to shift better! I think the slightly added load may be making it wait a little longer to shift and does less hunting back and forth. I haven't gone on a longer trip yet, which is usually loaded for camping and gets me up to the 18/19 range. But it doesn't look like there will be a material difference.

 

Good to hear! This is on your 2018?

 

I have had P265/70r16’s and 235/85r16’s on the stock 4:30 gearing. Now I have 255/85r16’s and 4:88’s.

Predictably, I got the best MPG bone stock, around 21 city 24 highway. With 235/85r16’s and a growing collection of mods, I was getting a reliable 19 city 22 highway.

I’m still breaking in my new gears so I don’t have accurate MPG for 33” tires and 4:88’s. But if you want an accurate speedometer/odometer with 33’s and 4:88’s, you need a 33403-39415 speed sensor gear. @turbodb figured that out so thank you! I’ve only got 50 miles on my new gears and tires but so far compared to GPS data, the new speed sensor gear is accurate.