Tire Weight vs Rolling Resistance

[Astro14]

Well, when you get to 1% changes in efficiencies, there really isn’t a practical difference. A 1% change can be measured across big samples, like a fleet, but for an individual and single vehicle, that change will be lost in the noise of the data.

It won’t make any difference in your MPG.

Since you’re choosing between two AT tires, pick the one you like better on the basis of noise, traction, tread life, or even looks, because the MPG difference between your choices won’t be measurable.

 

[CapriRacer]

And won't you take a gas mileage hit just because the tires are new?

Yes, new tires have a higher rolling resistance than worn tires, because of the increased amount of tread. I've estimated that the difference would be bout 5% on vehicle fuel usage.

Would I be right in thinking that all terrain tyres would generally fall into the grades with higher rolling resistance. I wonder how the OP determined that one tyre had a higher rolling resistance than the other. Even with no grading system yet in place, figures for the two tyres coefficient of rolling resistance in Kg per tonne could be translated in an effect on fuel economy.

Yes, for 2 reasons: Increased mass of tread rubber and the tread rubber composition. Tires designed for any sort of off-road usage will use rubber compounds that will be worse for RR.

I too wonder where the OP got the RRC values.

So allow me to explain the problem with translating RRC into actual fuel economy: Rolling resistance is distance dependent. To calculate the effect RRC has on fuel economy, it is proportional to the distance. But for steady-state driving the effect the car has tends to dominate things.

HOWEVER, there is a small speed effect - faster is worse. That's due to the additional distortion speed does to a tire.

But the effect the weight of a tire has on fuel economy is related to acceleration - frequent speed changes increases fuel consumption. In other words, weight has more effect on fuel economy in city driving, and less in country driving. But the weight of tires is relatively small compared to the weight of the vehicle, so the effect of tire weight gets overwhelmed.

So it is difficult to accurately estimate what change in RR has on actual fuel economy. Yes, better RR will result in better fuel economy, but how much? In my opinion, removing stuff from the car would have more effect.

 

[Boodro1]

I wonder how the OP determined that one tyre had a higher rolling resistance than the other.

Came from this online review: https://toptirereview.com/continental-terraincontact-a-t-vs-bfgoodrich-trail-terrain-ta/ taking this for what it's worth, but it's the only number I can find regarding rolling resistance. I also understand that I can be splitting hairs here, but I'm a sucker for optimization.

 

[mile9c1]

Putting a few more psi in the higher RR tire will get a lot more than the 1% back.

 

[mile9c1]

I recently bought a set of Vredestein Pinza AT tires for my 2019 Tacoma 4x4, and I love them!

I tried a set of set of LRE Pinza's earlier this year. And they exceeded my expectations. But they were noticeably stiffer than my previous highway P rated tires (duh). And I would have lost maybe 1.5mpg if I didn't pay attention... driving slower and coasting up to stops gained most of that back. Heavy tires like to roll!

 

[meep]

I'm in the process to researching new tires for my truck. 2019 F150 fx4, 95% pavement, and about 60 highway miles per day. Currently have Pirelli Scorpion All Terrain Plus XL's. They've been good but are getting loud and uncomfortable, so looking to go with a milder on-road all terrain tire. On my radar are the Continental TerrainContact AT2, and the BFG Trail Terrain T/A+. The Continental lists higher rolling resistance and lighter weight, while the BFG lists lower rolling resistance and higher weight by a few pounds.

My question is, what will have a more significant impact on fuel mileage, performance / feel, etc.. rolling resistance or weight?

I don't have much experience with different tire weights nor am I very familiar with the impact of rolling resistance differences. Thanks in advance for any guidance.

Having owned 2 sets of the continental AT I can say from experience that the mpg loss is not significant when staying in size. 1 mpg or less. Lifetime average (excluding towing) in my 2018 f150 was 20.9.mpg.

I also ran the Yokohama G015 and didn’t notice a difference that could be traced to the tire.

For an on-road AT, as these are called, they are IMO one of the best. I did keep them a few psi above placard, usually 35-36

 

[Sequoiasoon]

When I went from highway tires (Michelin LT bought at Costco) to AT tires (Nokian nAT) my MPG took a minor hit. Minor, but consistent.

If MPG is important, I would consider a highway tire like the Michelin Defender LTX. They were remarkably good in the snow, too.

Weight, on the highway, doesn’t matter much. Around town it certainly does. On the highway, rolling resistance is king, and the highway tire is the way to go.

@Boodro1 - I don't think it was noted or I missed it. What is the 5% off road that you do (sand/mud/rock crawl/other)? Where do you live and is snow an issue?

Like @Astro14 before he switched, I have Michelin Defender LTX M/S on my Pilot. I've had previous iterations of the same on multiple SUV's. They take me on the beach, state forest roads, gravel/rocks/light mud to hunting cabin. They have not let me down at any time. Mine will age out before wear out but might be same that goes on. Do they have that rough, tough off-road look, nope. But for me they work great in the daily drive, towing small trailer, quiet, good wet and dry. I can't say about snow as I run full winter.

You are focusing on rolling resistance for MPG. The more highway versions would be a better choice.

What parts are you looking to improve on, besides noise from the Pirelli? Tires are not an inexpensive investment but unless you really hate them, probably won't switch until worn out.

My 81yo father-in-law "needs to have" that look at me, I'm macho off road look. Reality he needs a Defender LTX M/S but wouldn't be happy with the look. The most off road he does is when he misses my driveway and ends up on part of the lawn or drives over a curb because he missed a driveway apron somewhere. I do think the Cooper looks great for that and bonus that they are quiet. The previous Falken Wildpeak AT Trail was also good for looks, it stayed quiet the whole time. It lasted about 30k of around town driving but so did the Pirelli Scorpion AT and OEM Falken Wildpeak HT01.

Focus on the needs of your daily use with priority, factor in some off road traction for what you actually do. In my opinion, rolling resistance when on a Ford F150 used for daily commuting should be way down if not off the list.

For me daily drive on 5-7 vehicles priorities - wet, dry, noise, use scenario, treadlife/cost, fitting appearance for vehicle. I don't think in 40+ years I ever worried about the LRR. If they happened to work out that way, great. I bought a naturally aspirated V6, I muzzled the cylinder deactivation, I want it running on 6, not concerned with the possible slight MPG increase running on 3. If I'm that concerned on the rolling resistance than I need a different vehicle (like the old school Honda insight I saw today driving home). Of course YMMV.

 

[Boodro1]

@meep I appreciate the info. I lost about 1.5mpg going from stock goodyears to the Pirelli's, and I don't have an appetite for another negative mpg hit. I'm not against another XL tire, but due to weight I'm looking to go back to an SL tire. The only towing I do is a 2000# bass boat.


@Sequoiasoon My use case has proven that the XL Pirelli's were a bit more than I need, so if I can go milder and improve MPG then that's what I want to do, which is why I'm looking into the two tires I mentioned. I had the LTX M/S 2 or defenders on every truck I've had before this one, so I'm very familiar with how great the tire is. The 5% offroad I deal with can be handled by the TerrainContact or the Trail Terrain. The Pirelli's have 43,000 miles on them and are getting close to the wear bars.

My focus is to better understand the different impacts that weight vs rolling resistance have on efficiency, since these tires have opposites of each.

 

[FZ1]

@meep I appreciate the info. I lost about 1.5mpg going from stock goodyears to the Pirelli's, and I don't have an appetite for another negative mpg hit. I'm not against another XL tire, but due to weight I'm looking to go back to an SL tire. The only towing I do is a 2000# bass boat.


@Sequoiasoon My use case has proven that the XL Pirelli's were a bit more than I need, so if I can go milder and improve MPG then that's what I want to do, which is why I'm looking into the two tires I mentioned. I had the LTX M/S 2 or defenders on every truck I've had before this one, so I'm very familiar with how great the tire is. The 5% offroad I deal with can be handled by the TerrainContact or the Trail Terrain. The Pirelli's have 43,000 miles on them and are getting close to the wear bars.

My focus is to better understand the different impacts that weight vs rolling resistance have on efficiency, since these tires have opposites of each.

Here's what I observed when I replaced oem Michelin Energy Savers LRR with Michelin Defender 2's on my '17 Camry. Highway mpg dropped about 10-15%, City mpg dropped 2-3% Defender 2's coast better. Think the Defender 2's are a tiny bit heavier. Ymmv.

 

[TacoFergie]

I think there is somewhat of a correlation, but it's not extreme in the same size, tire type and similar weights. On our 21 Subaru Ascent I have Falken AT Trail tires for summer and Nokian R5's for the winter on 2 sets of Fifteen52 17" wheels. The Falkens are a total of 63lbs each and the Nokians are 56lbs each while classified as low rolling resistance tires. I do notice that the car feels a little lighter on it's feet when I install the Nokians. However fuel economy is at best 1 mpg of eachother with the Nokian being slightly better.

On my previous Tacoma going from an E Load tire to a an XL tire dropped weight by about 15lbs per wheel, same size tires. Much more peppy feeling and picked up about 1-1.5mpg. But that 4.0L doesn't have much power to begin with and it's much more noticable on something like that.

 

[barryh]

Putting a few more psi in the higher RR tire will get a lot more than the 1% back.

It would need to be more than a 10% pressure increase to get 1% improvement in mpg and even then it's subject to a law of diminishing returns with subsequent increases in pressure producing smaller gains in mpg. If the manufacturers recommended pressures have already been upped to chase fuel economy, and they often are these days, then the easy gains are already gone and your are already into diminishing returns with any further increases. Much easier and much more comfortable to choose a low rolling resistance tyre in the first place.

 

[bdc101]

On my previous Tacoma going from an E Load tire to a an XL tire dropped weight by about 15lbs per wheel, same size tires. Much more peppy feeling and picked up about 1-1.5mpg. But that 4.0L doesn't have much power to begin with and it's much more noticable on something like that.

Over how many tanks and what method did you use to measure?

 

[edyvw]

I'm in the process to researching new tires for my truck. 2019 F150 fx4, 95% pavement, and about 60 highway miles per day. Currently have Pirelli Scorpion All Terrain Plus XL's. They've been good but are getting loud and uncomfortable, so looking to go with a milder on-road all terrain tire. On my radar are the Continental TerrainContact AT2, and the BFG Trail Terrain T/A+. The Continental lists higher rolling resistance and lighter weight, while the BFG lists lower rolling resistance and higher weight by a few pounds.

My question is, what will have a more significant impact on fuel mileage, performance / feel, etc.. rolling resistance or weight?

I don't have much experience with different tire weights nor am I very familiar with the impact of rolling resistance differences. Thanks in advance for any guidance.

BFG will suck in wet, ESPECIALLY compared to Continental. That would be first thing. Second, yes, unsprung weight definitely affects performance and mpg.
My choice would be Michelin Defender LTX M/S2 (I have them. Phenomenal tire) or Continental TerrainContact HT.

 

[TacoFergie]

Over how many tanks and what method did you use to measure?

241 total fuel logs in Fuelly. Without doing the math anddeep diving in Fuelly I'd say it was probably around 60 tanks (around 13k-15k miles) with the heavier tires before I sold them because I didn't like the ride quality and about 80 with the lighter tires before selling the truck. I filled up around 200-250 miles or once I hit a 1/4 tank most of the time. One other thing I noticed is less down shifiting to make climb certain hills on the highway when switching. I went from a Kenda Klever RT to the Duratrac RT. Both were fantastic as far as gripin many conditions goes.

 

[Vexorg]

I have literally never met a truck owner who cared to log their mileage or even put two seconds of thought into it, so I haven't seen any trustworthy data on the subject. Not like your average Prius owner who will keep a detailed gas log and write down how many minutes they used their A/C on every tank. (Which is a bummer because truck owners are the ones who would benefit from gas logging far more than any prius owner, simply because they typically use several times more gas as the average Prius owner)

My personal conclusion from almost 20 years of gas mileage logging (albeit not being a truck owner myself) is that there is no measurable difference in gas mileage when switching from a heavier tire to a lighter tire. I have also never been able to measure a difference between an LRR tire and a normal tire. Take all this with a grain of salt because it's just the limited data set I have been able to collect with my personal cars. I also don't drive that much over the past 10 years, so I don't buy new tires as often as I used to.

Maybe this is a great opportunity for @Boodro1 to do some empirical testing and come back with a conclusion?

I have 12 years of mileage logs for my 2014 Ram and over 3 sets of tires I can 100% guarantee there's no measurable difference in same sized tires. That said, if I removed the dates on the charts, I can tell you where I was going and if I was towing the holiday trailer or not.

 

[bdc101]

241 total fuel logs in Fuelly. Without doing the math anddeep diving in Fuelly I'd say it was probably around 60 tanks (around 13k-15k miles) with the heavier tires before I sold them because I didn't like the ride quality and about 80 with the lighter tires before selling the truck. I filled up around 200-250 miles or once I hit a 1/4 tank most of the time. One other thing I noticed is less down shifiting to make climb certain hills on the highway when switching. I went from a Kenda Klever RT to the Duratrac RT. Both were fantastic as far as gripin many conditions goes.

Excellent! Post the data or a link to your Fuelly page!

(I've been using Fuelly too, for all my cars since 2009) https://www.fuelly.com/driver/bdc