Mileage loss low Rolling Restance to std tire?

[sceva]

Hello all;

The tires on my 2014 Corolla, 205/55R16 89H Michelin MXV4 are on their last winter. They have been pretty good tires and still have decent tread left at 49000 miles but are not anywhere near as good on snow or wet that when newer. I will be replacing them before next winter and am strongly considering the General RT43's. I put a set on the wife's car and they have been great and at $86 compared to $124 each they are a bargain. My question is: The Michelin MXV4's are Green Technology Low Rolling Resistance tires while the General RT43 tires do not appear to be Low Rolling Resistance. Will I see any significant difference in mileage due to a switch in tire type?

Thanks

 

[Alex_V]

Can't offer a scientific perspective on this, but my Cruze had Firestone FR710's on it from the factory (a LRR tire as I understand) and switching to Uniroyal Tiger Paw (non-LRR) lost me 2.5 MPG. So there is a difference.

 

[Vuflanovsky]

I think that low rolling resistance is both a marketing and relative term in a lot of ways as I don't believe there's an official designation spec these tires would have to meet.

Having said that, I don't believe the RT43 is a particularly inefficient tire and that's probably backed by the Tire Rack comparison tests that include the RT43 where comparative MPG is listed. If I remember correctly, there's a web page either from General or a tire dealer organization that talks about the development of this tire...and fuel efficiency was part of the equation.

IMO, you'd probably see more of a difference between a strictly Eco tire versus the difference between the Michelin and the RT43.

 

[stephen9666]

Consumer Reports tests rolling resistance as part of their tire testing. I'm a subscriber so I just checked, and the RT43 H-rated is rated "very good" by CR in rolling resistance. The MXV4 is too old to be in their current testing, but the current Michelins tested in the all-season categories (Defender and H-rated Premier) also get "very good." The V-rated Premier does worse. Not that many all-season tires get CR's top score of "excellent" in rolling resistance.

Long story short, the RT43 is pretty highly rated as far as rolling resistance. It's not one of the few very best in that regards, but it's similar to or better than most.

CR measures rolling resistance on a dyno as part of their tire testing.

 

[CharBaby]

We have used both LRR & non-LRR tires on several vehicles and we can't notice any real measurable differences in mpg and, we measure the mpg on every tank of gas. They have all seemed about the same over several years and vehicles. In fact, some of the non-LRR tires have often done slightly better or as well as the LRR's.

 

[Virtus_Probi]

Here's what TireRack had to say about the RT43 vs. three other tires in a head to head showdown for which it had the highest road test scores for performance...
"Fuel Consumption Results

Our Real World Road Ride features a relatively flat 6.0-mile loop of 65 mph expressway, 55 mph state highway and 40 mph county roads along with three stop signs every lap. Our team drove each tire approximately 500 miles over the course of several days. Since we wanted to compare fuel consumption results that typical drivers would experience, our drivers were instructed to maintain the flow of traffic by running at the posted speed limits and sustain the vehicle's speed using cruise control whenever possible. They did not use hypermiling techniques to influence vehicle fuel economy.

Tire

Test MPG* - Gallons/Year@15,000 Miles - % vs. Most Efficient

BFGoodrich Advantage T/A Sport 31.4 477.7 -4.5%
Firestone Champion Fuel Fighter 32.8 457.3 --
General AltiMAX RT43 32.0 468.8 -2.5%
Pirelli Cinturato P7 All Season Plus 31.6 474.7 -3.8% "

215/60R16

http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=220

 

[barryh]

This doesn't help specifically but gives an insight into the range of savings possible from low rolling resistance tires.

There is Euro standard that requires tires to be labelled with one of 7 fuel efficiency grades A to G with a 7.5% spread in fuel consumption from best to worst. In practice the best fuel efficiency tires get an A grade and other good quality tires would be C grade or perhaps D at worst. For the most part only really cheap Chinese tires are worse than D.

What this means in practice is the best tires are typically 2% more fuel efficient than other quality tires and perhaps 4% or at most 5% better than the cheapest and worst tires.

 

[Kuato]

Based on the above - probably. And at $38 a tire or $144 for the set it would serve you well to calculate the fuel cost difference. If it is similar to what Alex_V experienced it may very well be less to buy the Michelins.

 

[sceva]

Looks like it's a close call.

Based on the Tire Rack tests the savings are the same as the increased fuel costs - So it's a wash

Based on Alex V's results ( 2.5 MPG loss ) LRR vs a Tiger Paw the extra fuel costs MAY be more than the savings.

I will probably go ahead and try them as, with retirement looming I will be driving less BUT I do want the apparently better Winter driving results the RT43 shows over the MXV4.

Thanks All

 

[nthach]

I saw a small MPG on between the OEM Goodyear Integrity and the Michelin Primacy MXV4, despite the fact they had the Green X LRR mark, and a bigger drop with the Defender XT. I now have my parent's old car and I have 40.1MPG on a fresh pair of Defenders. The best I saw was 45MPG on the OEM tires, 44MPG on the MXV4s.

Michelin originally introduced their Green X tech along with their Radial XSE casing, it was on all US-bound Mercedes S-Classes/BMW 7 Series and the Accords during the late 1990s as the Energy MXV4. The Integrity was born from a Chrysler or Ford need, but Toyota embraced them for the Prius.

 

[circuitsmith]

Keep in mind that the rolling resistance of a tire goes down a little as the tread wears down.
So you might see an MPG drop when replacing well worn "regular" tires with new LRR tires.
Rolling resistance is less important at high speed cruising because wind resistance is greater.
Same with stop and go city driving because so much energy is lost to frequent braking.
I got the best ever MPG in my current Matrix (38mpg) and my '88 Accord (37mpg) driving on the country roads of the Maryland eastern shore at ~50mph with very few stops.
This is the condition where rolling resistance would make the most difference.
I look forward to seeing how my Continental PureContacts (which are LRR) do out there this summer.

 

[sciphi]

Yep. There'll be a difference. Not sure how much, since it's dependent on the tire.

In my case, my Cruze had a set of LRR tires from the factory. Replacing them with a sportier tire made for a 10% drop in fuel economy.

 

[CharBaby]

On our Lexus RX that we owned for 14 years, we never saw much difference in MPG between(NONE are labeled LRR):

1) OE G/Y Integrity's...which show to have a low(er) rolling resistance!
2) G/Y Assurance Comfort Tread...which show to have a high(er) rolling resistance!
3) General AltiMAX RT43...again, show to have a low(er) rolling resistance!

In 14 years of reading my own MPG on each tank of gas on this particular Lexus RX(or any car), I never saw anything significant to make me want to spend more money on an LRR tire. Sure, I would occasionally have a really high or low tank/MPG but, that could be anything/reason. Incidentally, I have been reading my own MPG on all of our vehicles for over 40 years.

I have had(in the past), a tire brand/model or an oil brand/grade that gave me surprisingly better 1-2 MPG consistently over a lengthy period of time but, it's seems rare in my case.

What MPG that I do notice a difference in(since I am the one that fills the tank), is the difference between drivers of a particular vehicle. I achieve slightly better MPG per tank than does my wife. She does more stop&go and side street driving than I do. However, for highway driving, we're about the same per tank.

 

[i6pwr]

FWIW, any mileage loss is significant. When I went cheap and switched from my worn out Michelin Cross Terrain to a Kumho Ecsta, I lost 2-3 mpg. This was when gas was $3-4 gal and while my Envoy doesn't get the best mileage, I went from 270-280 miles per tank, 50/50 city/hwy to 230 miles per tank.

At 17K miles I sold the tires and went with the Lattitude Tour (Non HP) and regained that lost MPG.

At 40-50 miles per tank at about 16-17 MPG 50/50 mix driving, that's almost $12 per tank, almost $50 per month.

Not as bad now @ $2.10/gal, but I won't use anything but a LRR tire. I have the Defender LTX now and it's a supreme tire.

 

[sceva]

It makes you think

From the Tire Rack tests, The Pirelli Cinturato P7 did worse than the Altimax RT43's yet the Pirelli is a LRR tire while the General isn't rated as one.

Test MPG* - Gallons/Year@15,000 Miles - % vs. Most Efficient

BFGoodrich Advantage T/A Sport 31.4 477.7 -4.5%
Firestone Champion Fuel Fighter 32.8 457.3 --
General AltiMAX RT43 32.0 468.8 -2.5%
Pirelli Cinturato P7 All Season Plus 31.6 474.7 -3.8% "

 

[Vuflanovsky]

Yep, and...I'm sure the possibility exists that those MPG figures would be reversed in another test. There are several Tire Rack tests of the RT43 and, while I didn't look, I'm sure they don't perform in a lockstep manner with every MPG test.

Personally, I view the TR tests ( including the MPG data ) as more suggestive than something that's going to be particularly relevant to my vehicle and driving style. They typically use BMW test mules which are significantly different from my daily driver which is smaller, lighter, geared differently, etc. You might be able to extrapolate things but if the difference is .3 MPG, I have a hard time thinking with certainty that having that same tire put on my car is going to yield the same results as on their BMWs.