Tire Size and Fuel Economy

[Mushroom_Cap]

Just curious if anyone has any "real world" fuel economy numbers they'd like to share.

T4R currently has the stock size 265/65/70 tires on. I was pretty set on going up just a bit in tire size to 265/70/17 when I get new tires.

Several of my buddies are tying to persuade me to go with 285/75/17 (pretty sure that's the size....could have been a 70 series....I forget). Their argument is that this will look better and give me a bit more ground clearance.

I'm not too keen on going this big as I believe these tires would kill my fuel mileage, and be too noisy on the highway. Buddies say the difference on both of these will be hardly noticeable.

Would anyone care to comment?

It should be noted that I will be installing (well, a shop will be installing) a full OME front and rear lift which should give me 2.5-3 front and 1.5-2 rear lift.

It is also worth mentioning that if I stick with the 265/70/17 I can still get a P rated A/T tire (Duratrac), whereas if I go to the 285's I will have to go to a LT rated tire.

Am I being unreasonable? Will a 285/75 impact my fuel mileage that much? We do a lot of highway driving so gas mileage is a factor that must be considered.

I DO agree that the bigger tires look nicer, I just think the drop in fuel mileage and possible road noise negate the gain in appearance.

Finally, right now our 4Runner gets about 11-12 l/per 100km of mixed city/highway driving. Closer to 10 L/100km if all highway driving the speed limit. Tires are 265/65/17 Cooper Discoverer AT3.

 

[LOBO79]

I went with the Bfg KO2's 275/70/18 that are E rated which is a heavier tire, and I lost about 2.5 to 3 mpg. With that being said I wouldn't go back to stock size tires if it gave me 5 mpg. There is very little if any added road noise with the KO2's.

 

[Rocket61]

I went with the Bfg KO2's 275/70/18 that are E rated which is a heavier tire, and I lost about 2.5 to 3 mpg. With that being said I wouldn't go back to stock size tires if it gave me 5 mpg

yea if you're going to lift and run a larger tire, forget about the .5 mpg difference between 275 vs 285 or P rated vs LT.

 

[kevinpt]

Just curious if anyone has any "real world" fuel economy numbers they'd like to share.

T4R currently has the stock size 265/65/70 tires on. I was pretty set on going up just a bit in tire size to 265/70/17 when I get new tires.

Several of my buddies are tying to persuade me to go with 285/75/17 (pretty sure that's the size....could have been a 70 series....I forget). Their argument is that this will look better and give me a bit more ground clearance.

I'm not too keen on going this big as I believe these tires would kill my fuel mileage, and be too noisy on the highway. Buddies say the difference on both of these will be hardly noticeable.

Would anyone care to comment?

It should be noted that I will be installing (well, a shop will be installing) a full OME front and rear lift which should give me 2.5-3 front and 1.5-2 rear lift.

It is also worth mentioning that if I stick with the 265/70/17 I can still get a P rated A/T tire (Duratrac), whereas if I go to the 285's I will have to go to a LT rated tire.

Am I being unreasonable? Will a 285/75 impact my fuel mileage that much? We do a lot of highway driving so gas mileage is a factor that must be considered.

I DO agree that the bigger tires look nicer, I just think the drop in fuel mileage and possible road noise negate the gain in appearance.

Finally, right now our 4Runner gets about 11-12 l/per 100km of mixed city/highway driving. Closer to 10 L/100km if all highway driving the speed limit. Tires are 265/65/17 Cooper Discoverer AT3.

if your wanting to get a bit more ground clearance and not wanting to kill your gas mileage you could go with 255/75/17(32")

 

[Tooltime19]

I lost about 2mpg at most. I love my tires, the load range and the clearance so like someone above said, you can have my lost mpg. The added safety of the grip off road is worth it in my book. Im building an off road rig not a silent road car like my daughters Prius.

 

[srs034runner]

4.7 V8 AWD
Currently running 33" mud terrains, with 3" lift, and grabbing about 15.3 city/17.9hwy/16.7 combinedishhhh ... very happy with it, i'm not a grandma either! lol

 

[wadle5]

Agreeing with [MENTION=77471]kevinpt[/MENTION]. But instead of getting a wider tire you could always get a set of pizza cutters like him or me being cautious went with 255/70/17. I previously had 265/70/17.

What you need to take into account is in calculation of MPG's your tripmeter and speedometer is going to be off due to your difference in tire size. This is going to read different on your lie-o-meter. So what you would need to do before you can even compare accurate mileage would be a speed-ohealer or get a GPS with mileage and tripmeter and than use those figures when calculating your fill up.

Good Luck!!

 

[S p a r k y]

We have all been in your shoes at some point. If you go with 285/70 chances are you won't wonder what if, unless 35's have been in your thoughts.

285 LT Dura's will be less mpg than a 265 P Dura n o doubt. I have 285's and so glad I do, looks awesome. I do consider going smaller to save mpg but when it comes down to it, I don't want any smaller now that I have 33's, I may at some point go narrower though. I get avg city/highway 16mpg

If your wanting taller and tougher looking with keeping good mpg. I would definitely suggest the (P-rated) Dura's in 265/70 or 255/75. 255/75 is half inch taller than 265/70. 265/70 is half in wider than 255/75.

 

[S4TA]

I have said it before, but I wish they made a 265/75/17. It is about the same overall diameter as 285/70, but obviously not as wide.

 

[Dylan]

if your wanting to get a bit more ground clearance and not wanting to kill your gas mileage you could go with 255/75/17(32")

x2 on the 255/27/17 size.

I went with the Firestone Destination A/T...it's about 32.5" tall, so nearly a 33". It has less width at 10" than stock at 10.5", however, so less rolling resistance.
It's 43lbs, so heavier than stock at 36lbs. It's C rated so it's lighter than an E rated but still a LT.
I wanted a LT tire but didn't feel the need to go all the way to a E load range.

 

[CXS]

I'm running DuraTrac 285/70/17's which is a pretty good size for my use but I'm thinking of going skinnier since I rub on the swaybar and fender well when stuffed off-road. The mpg hit is about 2mpg though I'm guessing.

Anyone running skinnies? What size and brand do you like?

 

[wadle5]

I'm running DuraTrac 285/70/17's which is a pretty good size for my use but I'm thinking of going skinnier since I rub on the swaybar and fender well when stuffed off-road. The mpg hit is about 2mpg though I'm guessing.

Anyone running skinnies? What size and brand do you like?

I recently just switched to General Grabber's and love them thus far.

 

[CXS]

I recently just switched to General Grabber's and love them thus far.

What size you running?

 

[wadle5]

What size you running?

Since I still have stock UCA's and such I just did 255/70/17. Definitely looks mean compared to my fatter BFG A/Ts.

 

[Dylan]

I'm running DuraTrac 285/70/17's which is a pretty good size for my use but I'm thinking of going skinnier since I rub on the swaybar and fender well when stuffed off-road. The mpg hit is about 2mpg though I'm guessing.

Anyone running skinnies? What size and brand do you like?

Define skinnies....mine are 10" wide and 32.5" tall

 

[CXS]

Define skinnies....mine are 10" wide and 32.5" tall

That sounds like what I'm interested in, what's the metric size? That stuff confuses me, why they switched is beyond me.

 

[Dylan]

That sounds like what I'm interested in, what's the metric size? That stuff confuses me, why they switched is beyond me.

255/75/17, I have mine on stock 5-spoke 17" wheels.

You might also have luck with 33x10.50r17 which is pretty similar in the High Float tires.

 

[CXS]

Thanks Dylan!

 

[Mushroom_Cap]

Thanks for the replies guys.

Some good thoughts on going with the skinnier tire, 255/75/17. Personally, though, I don't like the look of the skinnier tire. Looking at a spec sheet here for the duratracs...I see the 255/75s are a 32" tire, and comes in P rated. The 265/70s are a 31.7 inch tire. So the difference in tire height are pretty negligible as far as I can tell.

The tire I'd like to get if looks were the only factor are the 285/70/17. They look sharp! However we do drive a fair bit on the highway so the # of miles I am getting each tank is somewhat important. The mileage took a bit of a hit going from a HT tire to an AT tire. I can live with that as the HT tire was not suitable for the type of driving we do in the fall when we hunt/fish/camp.

However I'm a bit worried about "mileage shock" going up to a 33" e rated LT tire. I'll have to re-read a few comments and convert the mpg to L/per 100km and think about it.

Buddy I work with had a good suggestion today. He said get your new OME shocks/struts installed and drive it around for a couple months. Give it a bit of time to "settle" a hair or two. Yeah it'll look a bit goofy with the stock tire size on but who cares. THEN, go to a tire shop where you plan to buy the tires and have them put the 265/70s on. If you are happy with the look, then get them.

I am hoping I like the look of the P rated 265/70/17 duratracs. If I think, nah, they still look too small, have them pop them off and slap on the 285/70s. Assuming there are no major issues with rubbing, get the 33" tires and just live with the drop in mileage.

LOBO79: how do you find the E rated tires ride? Pretty hard on the bumps? Or hardly noticeable? I am also a bit worried that an E rated LT tire will be too harsh on small bumps on rough roads.

 

[jacob7071]

I'm kinda in the same boat. I want to add a 1" BL and go up to 285s when my tires are done - most likely this summer or surely before next winter - but I also want to stay with a P rated. I know the Toyo Open Country AT 2 comes in a P285/70/17 (and I believe the Cooper Discoverer AT3 does also). I've had the Coopers in a P265/70/17 for about 50K miles. They've been great, but have been tough to balance over the past 5-10K miles. I'm pretty sure I'll be going with the Toyos when it's time to replace