New tires: MPG way down

[NJGuy]

Originally Posted by silvergga

To me, tires' main purpose is to keep me safe and alive. mpg is just another parameter of cost to run a car.

I don't disagree with you, but some people don't need all the extra traction and put cost high on their priority list. Maybe the LTX isn't the tire for them.

Originally Posted by silvergga

What is the per mile cost to run your tires? Will they actually last until the manufacturer's warranty? If not, how much does it cost to install another set? Do the tires ride safe until 2/32" or do they ride unsafe at 4/32" and force you to replace them pre-maturely, thus increasing the per mile cost?

For some people, the cost may be significant. I did some quick and dirty calculations, pitting up the cost of 2 sets of GY integrities vs. 1 set of LTXs, assuming a treadlife of 100k for the Michelins and 50k for each set of the GYs. I came up with a cost difference in favor of the GYs of about a hair under $20 per month, and it looks like fuel cost trumped the tire acquisition/installation costs over the life of the tires. The cost difference was about $0.02 per mile; but over the life of the tires, that's almost $2k.

Other assumptions: $3.50/gal, 1k miles/month, 2.5 mpg difference (between the 2-3 mpg) reported by OP, today's tirerack.com prices plus $60 per set for delivery & $80 per set for installation.

1. I hope my math and methodology were correct . If not, feel free to throw in all your criticism; I'll put on my flame suit.
2. I kept the costs fixed for simplicity.
3. Yes, there are so many variables that I may not have even considered... but again, I wanted to keep it simple.
4. YMMV

[silvergga]

Originally Posted by NJGuy

I don't disagree with you, but some people don't need all the extra traction and put cost high on their priority list. Maybe the LTX isn't the tire for them.

For some people, the cost may be significant. I did some quick and dirty calculations, pitting up the cost of 2 sets of GY integrities vs. 1 set of LTXs, assuming a treadlife of 100k for the Michelins and 50k for each set of the GYs. I came up with a cost difference in favor of the GYs of about a hair under $20 per month, and it looks like fuel cost trumped the tire acquisition/installation costs over the life of the tires. The cost difference was about $0.02 per mile; but over the life of the tires, that's almost $2k.

Other assumptions: $3.50/gal, 1k miles/month, 2.5 mpg difference (between the 2-3 mpg) reported by OP, today's tirerack.com prices plus $60 per set for delivery & $80 per set for installation.

1. I hope my math and methodology were correct . If not, feel free to throw in all your criticism; I'll put on my flame suit.
2. I kept the costs fixed for simplicity.
3. Yes, there are so many variables that I may not have even considered... but again, I wanted to keep it simple.
4. YMMV

Yes, I agree a difference in mpg will cost more vs tire cost, especially if it is 3mpg. However, I also doubt the difference will be that high over the life of OP's new tires. OP was comparing mpg of worn out tires vs brand new tires, and the LTX M/S2 were not known for mpg. In CR's test, the LTX M/S2 only received "good" for rolling resistance despite being rated for the best overall, FWIW. There are tires that are rated "very good" and "excellent" for rolling resistance.

The bottomline is, most drivers liked the LTX M/S2 not because of their mpg performance, and apparently OP put a lot more focus on mpg vs the average driver.

[xGS]

Originally Posted by NJGuy

1. I hope my math and methodology were correct.
If not, feel free to throw in all your criticism; I'll put on my flame suit.

3. Yes, there are so many variables that I may not have even considered... but again, I wanted to keep it simple.

Two factors not consisdered:
1) The new tires have higher rolling resistance, which will reduce over time.
2) The new tires have a larger diameter, which will reduce over time.

It's highly likely that the observed difference in mpg is entirely due to the combination of smaller diameter and lower rolling resistance of the old, worn-out tires versus the larger diameter and initially higher rolling resistance of the brand-new, tires with full tread depth.

Refer to this explanation: Tire Tech Information - Tire Rolling Resistance Part 3: Changes to Expect When Switching from Worn-Out to New Tires

[silvergga]

For people interested, below are 4 instrumented MPG tests by tirerack on passenger and SUV eco-friendly tires. These are apple-to-apple comparisons, and are all within, at most, ~2% of each other, except for 1 test involving the Continental LX20 w/ EcoPlus which showed -4.4% for that tire.

It actually correlates well with CR's rolling resistance score of just "good" for the LX20, despite its "EcoPlus" name. "good" is just the middle score - 3/5. FWIW, the LTX M/S2 also scored just "good" on CR. It appears that MPG difference due to tire choice shouldn't be more than +/- 5%, with everything else being equal, which is about 1mpg for the Pilot?

Tire Test Results : Eco-Focused All-Season Tires: Do They Deliver on the Promise?
Tire Test Results : Eco-Friendly All-Season Tires — How Does Performance Measure Up?
Tire Test Results : Testing Eco-Focused Crossover/SUV Touring All-Season Tires
Tire Test Results : Testing Eco-Focused Crossover SUV All-Season Tires in Real World Conditions

Too many factors outside of tire design affect mpg - tire wear, alignment, engine condition, air filter condition, etc etc... I am really interested to find out when OP's tire have 30-40k on them, whether the mpg difference is still 2-3mpg, or closer to 0-1mpg (~5%). Personally, I think we are splitting hair on an item that our lives depend upon.

[NJGuy]

Originally Posted by silvergga

Yes, I agree a difference in mpg will cost more vs tire cost, especially if it is 3mpg. However, I also doubt the difference will be that high over the life of OP's new tires. OP was comparing mpg of worn out tires vs brand new tires, and the LTX M/S2 were not known for mpg. In CR's test, the LTX M/S2 only received "good" for rolling resistance despite being rated for the best overall, FWIW. There are tires that are rated "very good" and "excellent" for rolling resistance.

The bottomline is, most drivers liked the LTX M/S2 not because of their mpg performance, and apparently OP put a lot more focus on mpg vs the average driver.

Ok, then let's say over the entire life over the tires, the mpg difference is less. A 1.5 mpg difference comes out to $900 over the tire lifetime, and a 2 mpg difference is about $1400. Still not insignificant.

I think that the LTX M/S 2 is an incredibly sexy tire, and I understand why it receives so much praise. For many, it is close to perfect; but the slight mpg hit is a tradeoff. You'll always hear the owner's praise its performance, but you'll hardly ever hear about a reduction in gas mileage. After all, it's a truck/suv tire, purchased mostly by men. And it's mostly men who pay attention to and care about tire performance specs, and the mpgs much less .

Yes, we're splitting hairs here... but for some people, the hairs may be a bit thicker . I just felt like stirring the pot a little, that's all .

[rocky]

There is more than mpg to the trade off v GY tires

GY grip in rain and snow is disgraceful. Confidence and less likelihood of an accident have value.

Hell, even a 05 owning buddy of mine who would win the cheapskate of the year award anytime, bought the LTX MS2 without knowing I had them.

Tire life is significantly more with the LTX. I got 48k from my GYs before they turned into sieves and couldn't hold air any longer. after 50,000 miles on the LTX I still have at least another 25-40k wear to go. with the GYs I would now be spending another $600 on new tires.
The michelins cost $684 for a set of four from Tirerack less a $70 rebate = $614
The Gys costs $520 for four from Tirerack.

Regardless of my point of view, you need to make your own decisions, based on your own needs, wants, preferences and desires.