255/75/17 or 265/70/17
- Thread starter Nashvillerunner
- Start date
CJ3Flyr
Super Moderator
I had a rare, bizarre issue with my 255/75's that got me out of them. I loved them. I thought they looked good, worked well and I also noted equal or slightly better mpg.
My calculation method for my mpg was as follows:
-using a GPS tripmeter I figured out odometer error. I then went and figured out odometer error using the measured mile sticks on the interstate. They matched. Once done with that I figured a correction factor of roughly 5.5% (under reporting). Mine under-reported miles by 2.5-3% with OE tires but the speedo was dead-on.
-using the correction factor at virtually every tank of fuel I determined that my mileage was the same or a little better. For certain types of driving such as slow interstate driving (55-65mph) it was a lot better, a full mpg when running 36psi.
-I know about the hazards to the evap system but I 'brim it' every fill-up anyways so there's no variation between fill-ups.
I am on super-easy rolling 265/70 Toyo H/T's now. They are great tires. My around town mpg is fine but my fast highway driving mpg is down a touch from the 255/75's. Basically I went from 265/65/17 Michelin CT's to the GYSA's with no mpg penalty which was amazing IMHO.
I'm all about the 255/75's for the 4Runner and I like tall skinnies in general. Wide tires, to me, just equal hydroplane, poor mpg, hard to balance etc. They do give great dry traction and work well on the beach I guess but those don't matter much to me these days. I drive like an old fart and don't get on the beach much...
Good tall-skinny article here: Expeditions West: Tire Selection for Expedition Travel
My calculation method for my mpg was as follows:
-using a GPS tripmeter I figured out odometer error. I then went and figured out odometer error using the measured mile sticks on the interstate. They matched. Once done with that I figured a correction factor of roughly 5.5% (under reporting). Mine under-reported miles by 2.5-3% with OE tires but the speedo was dead-on.
-using the correction factor at virtually every tank of fuel I determined that my mileage was the same or a little better. For certain types of driving such as slow interstate driving (55-65mph) it was a lot better, a full mpg when running 36psi.
-I know about the hazards to the evap system but I 'brim it' every fill-up anyways so there's no variation between fill-ups.
I am on super-easy rolling 265/70 Toyo H/T's now. They are great tires. My around town mpg is fine but my fast highway driving mpg is down a touch from the 255/75's. Basically I went from 265/65/17 Michelin CT's to the GYSA's with no mpg penalty which was amazing IMHO.
I'm all about the 255/75's for the 4Runner and I like tall skinnies in general. Wide tires, to me, just equal hydroplane, poor mpg, hard to balance etc. They do give great dry traction and work well on the beach I guess but those don't matter much to me these days. I drive like an old fart and don't get on the beach much...
Good tall-skinny article here: Expeditions West: Tire Selection for Expedition Travel
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Conspearasea
New member
I don't have much of "dog in this fight" so to speak, but have been reading along none the less. I am rather surprised at the loss of mpg that the +1 guys are reporting. I would not have expected such a hit just going to the 70s over 65s.
Prior to my recent lift/wheel/tires swap, I hand calculated my mpg w/ GPS miles over a 750 mile trip. One tank netted me 20mpg the next tank was 19mpg. My average speeds run around 75-78, occasionally faster, fairly flat interstate driving.
Installed a 3" Toytec ultimate lift kit, 275/70/17 BFG ATs, and new Pro Comp wheels. My wheel well measurements at the center of the rim were
Before- Front 33.25", and Rear 35" (average between driver and pass)
After- Front 39.5" and Rear 39.5" (again avg between driver and pass). Pass side is slightly higher
Between the suspension lift and larger tires, I gained more than I actually expected. Much more than others have reported w/ this lift kit.
I ran the exact same 750 mile trip after the lift, and calculated again by GPS miles and I got 17 MPG.....my last tank I actually believe is going to be more like 17.5 mpg.
I figure I lost between 2-3 mpg, but that's with a substantial lift, 275/70 E rated BFGs.....actually about what I expected. I would have never thought that the guys running 265/70 w/ a 1-2" lift would have had a hit like mine or even close.
Prior to my recent lift/wheel/tires swap, I hand calculated my mpg w/ GPS miles over a 750 mile trip. One tank netted me 20mpg the next tank was 19mpg. My average speeds run around 75-78, occasionally faster, fairly flat interstate driving.
Installed a 3" Toytec ultimate lift kit, 275/70/17 BFG ATs, and new Pro Comp wheels. My wheel well measurements at the center of the rim were
Before- Front 33.25", and Rear 35" (average between driver and pass)
After- Front 39.5" and Rear 39.5" (again avg between driver and pass). Pass side is slightly higher
Between the suspension lift and larger tires, I gained more than I actually expected. Much more than others have reported w/ this lift kit.
I ran the exact same 750 mile trip after the lift, and calculated again by GPS miles and I got 17 MPG.....my last tank I actually believe is going to be more like 17.5 mpg.
I figure I lost between 2-3 mpg, but that's with a substantial lift, 275/70 E rated BFGs.....actually about what I expected. I would have never thought that the guys running 265/70 w/ a 1-2" lift would have had a hit like mine or even close.
Kmvreter
New member
Sorry if I'm confused reading this.
You love them and go on explain the mpg so what is the rare, bizarre issue that got you out of them?
CJ3Flyr
Super Moderator
The tires I had wouldn't play well with my rims and they would rotate on the rims. This made it impossible to keep them balanced for more than a couple of hundred miles at a time. I, admittedly, out of frustration, dumped them. My tire store wouldn't buy off on sanding the rim where the bead contacts. I should've insisted. It was some crazy issue about the paint on the rim and the rubber not "sticking", not a high enough coefficient of friction...
I suspect scuffing the rims would have taking care of it.
:cheers:
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I think you got your measurements wrong or you measured from the ground to the wheel well and part of that 6.25/4.5" lift came from the tire height. Never the less, 2-3 mpg isn't too bad with that lift and tires. If you'd slow down you might even get back to around 19-20
By the way, what is the offset on your rims? I like how far they sit out.
Conspearasea
New member
Yep the measurements were from the ground to the top of the wheel well, including the difference in tire height. Each measurement was taken at the center of the wheel on flat concrete. Reason I posted those is to show how much of an overall lift the vehicle got related to my mpg loss. The truck really does sit pretty high now, higher than expected, which I like!!
My wheels are 17x8 w/ 4.5 inch backspacing and zero offset.....They work out perfect for the 06+ wheel wells. They barely stick out in the rear, looks great to me.
Again, I was shocked that my mpg loss wasn't too bad, and you are right! slowing down would give me much better mpg, but w/ a 750 mile ride ETA is more important than MPG for me after 12 hours in the car.
Good luck to all no matter what tire you use, I just wanted to share that my mpg hit wasn't much more than skinny 32" tires based on some experiences here.
My wheels are 17x8 w/ 4.5 inch backspacing and zero offset.....They work out perfect for the 06+ wheel wells. They barely stick out in the rear, looks great to me.
Again, I was shocked that my mpg loss wasn't too bad, and you are right! slowing down would give me much better mpg, but w/ a 750 mile ride ETA is more important than MPG for me after 12 hours in the car.
Good luck to all no matter what tire you use, I just wanted to share that my mpg hit wasn't much more than skinny 32" tires based on some experiences here.
gm350reratliff
New member
I have seen and heard of other goodyear tires doing this. Kind of scary to think about. Thanks for letting us know.
WXman
New member
Old thread...but everybody says "use the search function" so here ya' go. For you guys that've been running 255/75 for a while now, what's your overall MPGs looking like compared to stock?
I am averaging 16.5 on my daily routine bone stock (small lift kit) right now. I just picked up some 255/75-17 Kenda MTs and they are pretty beefy at 51 lbs. each. With the taller tire, knobby tread, and more weight.. I'm concerned that my fuel economy might drop off the cliff.
In the past, I've always seen about 1.5 MPG loss from upsizing tires just a little. Are you guys still finding that to be the case with your 265/70 and 255/75 sizes?
For you guys that've been running 255/75 for a while now, what's your overall MPGs looking like compared to stock?I am averaging 16.5 on my daily routine bone stock (small lift kit) right now. I just picked up some 255/75-17 Kenda MTs and they are pretty beefy at 51 lbs. each. With the taller tire, knobby tread, and more weight.. I'm concerned that my fuel economy might drop off the cliff.
In the past, I've always seen about 1.5 MPG loss from upsizing tires just a little. Are you guys still finding that to be the case with your 265/70 and 255/75 sizes?
phqduphead
New member
I have had my 255/75/17 GYSA for two years now and get around 18.5-19 highway at 65-67 mph and get 14-15 city. This is with the V8 4WD and 3" front 1" rear. The tires ride very nice.
WXman
New member
Yeah one thing I noticed when I got this 4R is that with the 265/65 tires the speedometer was about 2% fast. I figured this out using GPS.
Now, with the 255/75 it seems to be about 2.5% slow.
The reason this is important is that the display always read 2.0-2.25 MPGs too high at the end of the tank. Since adding the 255/75 tires, the display is reading a lot lower and it makes it seem like I've lost a ton of gas mileage, but I'm hoping that it's just because the display is reading closer to reality now.
These tires are certainly heavier, taller, and have deeper tread....all which will work together to destroy gas mileage. But I'm hoping that the true drop is only about 1.0 MPG instead of the 2.0 MPG that the display is indicating.
Now, with the 255/75 it seems to be about 2.5% slow.
The reason this is important is that the display always read 2.0-2.25 MPGs too high at the end of the tank. Since adding the 255/75 tires, the display is reading a lot lower and it makes it seem like I've lost a ton of gas mileage, but I'm hoping that it's just because the display is reading closer to reality now.
These tires are certainly heavier, taller, and have deeper tread....all which will work together to destroy gas mileage. But I'm hoping that the true drop is only about 1.0 MPG instead of the 2.0 MPG that the display is indicating.
MAST4R
New member
265 to 255 comments?
Can anyone who switched from 265 70 to 255 75 on a 5th generation comment on road performance?
For now, I remain happy with my P265 70 17 Wildpeak, but I am not comfortable without a plan B.
255 75 17 offers light weight, mild load capacity yet strong offroad choices whereas 265/275/285 width sizes do not. Specifically, there are LT-C MT tires with 3-ply sidewalls in 255 75 and the taller tire will add comfort on and offroad.
BUT, these 255 75 17s come with dismal speed and load ratings. No, I don't go that fast. But speed ratings matter not just for top speed. 111Q is the typical 255 75 17 MT tire and that just looks awful on paper when the Wildpeaks are 115T (though take 10% off for being P-metric on BoF SUV).
I am specifically interested in hearing about the cornering performance of 255 75s and especially of MT 255 75s.
Can anyone who switched from 265 70 to 255 75 on a 5th generation comment on road performance?
For now, I remain happy with my P265 70 17 Wildpeak, but I am not comfortable without a plan B.
255 75 17 offers light weight, mild load capacity yet strong offroad choices whereas 265/275/285 width sizes do not. Specifically, there are LT-C MT tires with 3-ply sidewalls in 255 75 and the taller tire will add comfort on and offroad.
BUT, these 255 75 17s come with dismal speed and load ratings. No, I don't go that fast. But speed ratings matter not just for top speed. 111Q is the typical 255 75 17 MT tire and that just looks awful on paper when the Wildpeaks are 115T (though take 10% off for being P-metric on BoF SUV).
I am specifically interested in hearing about the cornering performance of 255 75s and especially of MT 255 75s.
