Wheel weight and mpg

Donstar · June 17, 2016

In the past, I have noticed wider tires harm MPG more than say a tire that is narrower but a bit taller. Wide tires have a bigger contact patch, which is good for traction in some cases, but it also adds a huge amount of rolling resistance.

Example, I have seen better MPG with say, a 34 inch tall tire that is 11 inches wide, over a 33 inch tire that is 12.50 inches wide. Don't get carried away with the width. Also, the lightest A/T truck tire is the Duratracs. Check a tires weight before you buy. Some smaller Toyo A/T tires are still in the 70+ pound range. Compared to stock tires that weigh 45-48 pounds, it is a HUGE difference.

More sidewall, less wheel. Tires can flex, wheels can't. Always go for a smaller wheel and more sidewall. Big wheels like 20s and 22s put a real damper on performance and economy.

Stock tires on my truck are 255/70/17. I am looking at 265/7017. This is not much of a size difference but look better IMO. I often thought that 255/75/17 may be even a better look. A 275 is not available on a Michelin 70/17 and 285 is getting a little too big for my needs and wallet!.

kstruckcountry · June 17, 2016

I didn't know they put 255/70R17 on any. I thought they were all 255/75R17. 265/70R17 has been plenty of tire for me.

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Donstar · June 17, 2016

I didn't know they put 255/70R17 on any. I thought they were all 255/75R17. 265/70R17 has been plenty of tire for me.

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You're correct in saying that the 265/70r/17 is plenty of tire. It wasn't that long ago that this would have been considered a huge wheel and tire size combination!

tyrich88 · July 27, 2016

So I just posted this in another thread, but i think I may get better feedback here...

Anyone have any experience with oversized tires that are NOT 10ply?
I have 275/70/18 BFG KO2's right now, and while i love them, they MPG loss is pretty substantial because they are pretty heavy.
I'm debating going to some 285/70/17s with new wheels. Nitto makes a terra grappler G2 in a standard P rated casing and I'm not offroad much at all and don't tow much either so wondering if these would be a better option for me because of their lighter weight.

They are a similar outside diameter (275/70/18 is about 33.2 and 285/70/17 is about 32.8 but since BFG's run small in my experience, they are probably about the same diameter). They are the height i would prefer to have as i like the look. But the weight of the lighter casing tires is quite a bit less. The nitto Terra Grappler in a 285/70/17 P casing is 44.5lbs while the BFG AT KO2 i have in 275/70/18 Load range E 10-ply casing is 57.7 lbs (weights are according to Amazon). So losing about 13 lbs per corner just in the tires. (The wheels i'm looking at, I believe, are lighter than stock as well)
Just wondering how the tires perform in this casing as i feel like they will help with gain back some power loss from the heavier tires and get some MPG's back as well.

newdude · July 27, 2016

You already have GM's lightest wheel they make for the 1500 truck. The factory tire (Bridgestone Dueler HT D684 p255/70/17) comes in at 36.41lbs. P load 265/70/17 Michelin Defender LTX MS comes in at 39.9lbs. In LT265/70/17 E that tire is 48lbs. You will have picked up 11.59lbs per corner with the LT Michelins, and 3.49lbs if you went P Load Michelins. Size changing doesn't really add much, and the LT jump isn't that big either to where it should hurt MPG (Probably 1mpg or less, maybe closer to 1/2).

An LT tire will add weight, sure, but the penalty might not be really noticed if you set the pressures right (lower pressure = more resistance, higher pressure = less resistance). So it could be counteracted by going above the door PSI to say,45-50psi. Your ride may change a bit however going P to LT. My experience? Not that much ride difference. Bumps is where you may feel a change but highway, they ride near equal.

I didn't know they put 255/70R17 on any. I thought they were all 255/75R17. 265/70R17 has been plenty of tire for me.

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The standard tire was 245/70/17 on the GMT-900 with optional 265/70/17. For 2014, because they added 1/2 an inch to the wheel width, they had to make the base tire wider, hence the base tire is now a 255/70/17 and the optional is 265/70/17.

newdude · July 27, 2016

Also, the lightest A/T truck tire is the Duratracs. Check a tires weight before you buy.

...And in what size might that be...?

Andy Seibel · July 27, 2016

Increasing the weight of a tire by 10 pounds should really only affect mileage during acceleration. So I would have to believe two equal sized tires of different weight would have negligible difference on mileage on the highway. If you are in stop and go traffic, yes it will affect the results more.

The bigger issue is that heavier tires likely have more aggressive tread, or are wider, and both of those will hurt your mileage more.

I still laugh when people want to spend $1000+ to change their tires on a truck just for looks, but are concerned about the gas mileage. Larger tires will always lower your mileage. Its science.

kstruckcountry · July 27, 2016

Going from a 32 to a 33 alone would change your gearing by 3% or so.

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tnchevy · July 27, 2016

Tread pattern has a lot to do with what kind of mpg's you are getting. Add that with a taller - wider - heavier tire then you are going to lose mpg's. My company work trucks lose about 2.5 mpg's on average when we ditch the factory tires and put on bigger LT tires. That is with the speedo corrected.

tyrich88 · July 28, 2016

Tread pattern has a lot to do with what kind of mpg's you are getting. Add that with a taller - wider - heavier tire then you are going to lose mpg's. My company work trucks lose about 2.5 mpg's on average when we ditch the factory tires and put on bigger LT tires. That is with the speedo corrected.

Tires arent any wider, they are taller and a lot heavier though.

I figure I lost 2-3 moving to the 10plys, i also think i lost a few adding a grill guard to my truck. My highway mpg is down to around 15 from the 20+ I used to get. So I'm just curious how much each of those would play into it... maybe I can find a happy medium.

kstruckcountry · July 28, 2016

The best I could do on the highway in my 2006 pre bumper was 18.5. After, the best I could do was 18.5. It didn't change a thing. And it's more substantial than most.

I went from 4 ply SR-A's to 10 ply Cooper ATP's, still 18.5 on the highway. I did stick with stock diameter. Maybe they hurt in town mileage some, like any addition in weight, but driving style is the biggest factor.

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tnchevy · August 1, 2016

The best I could do on the highway in my 2006 pre bumper was 18.5. After, the best I could do was 18.5. It didn't change a thing. And it's more substantial than most.

I went from 4 ply SR-A's to 10 ply Cooper ATP's, still 18.5 on the highway. I did stick with stock diameter. Maybe they hurt in town mileage some, like any addition in weight, but driving style is the biggest factor.

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I think a lot of it how these new 6 speed (and now 8 speed) transmissions work when it comes to mgp's and bigger/heavier tires. My 2002 with the 4.8 motor/ 4 speed trans/ and 4.10 gears was similiar to your 2006. It got pretty much the same gas mileage for my driving style with both the factory street tires and the heavier Nittos and Cooper LT tires that I later put on it. I had several work trucks during that time period that didn't lose much mpg's either with heavier tires. My current work truck is a 2012 Ford with a 6 speed, 5.0 V8, and 3.55 gears and it lost 2.5 mpg with a size bigger (and much heavier) Goodyear AT kevlar tires.

truckguy82 · August 1, 2016

P rated is fine, my Denali comes with Goodyear Eagle LS-2's P rated, they where the same tires on my 2013 Denali ok tire for stock, & I tow 7000lbs in the summer. I would replace with P rated Michelin if I had to buy new tires.

side note, I really do miss my AWD Denali, never had traction issues, theses' new truck's I can fry the tires, and when wet they are almost useless, I need tank tracks for this truck.

?

4wd auto, you should use it

I get horrible traction in the wet in 2wd, but in 4wd auto it gets considerably better traction than most run of the mill fwd bias AWD systems

15silver · August 1, 2016

if loaded or towing within the mfgr's spec for your vehicle - on a 1500 - a P rated tire is fine.

Going to an LT, you'll have to up the tire pressure.

Increasing tire diameter will affect MPG.

Adding weight affects the suspension via more un-sprung weight. Also accelerating rotating mass is aprox 3 times more energy than the same amount of vehicle mass ... so affects MPG too.

Likely won't notice much going up one size, but would notice a diff going to LT.

I was thinking of going to LTs, but after researching it, have decided to keep stock diameter and stay with a P rated tire.

Had it down to the Michelin Defender LTX's and KO2s. I like the look of the A/T's, but not sure I want more road noise, and a stiffer heavier tire. Only bad thing I can say about the Duelers that come with, is is they suck in the rain. If they didn't spin with very little pedal, I likely wouldnt be considering a change.