Not thrilled with the Continental Pure Contact "Eco Plus" tires

the eco part is a scam. they are not really LRR. i was duped into buying them and the MPG immediately went down from about 65 to 55 (city driving, P&G style, same commute and same everything). if someone else told me i wouldn't believe it. 30,000+ miles later still stuck on 55 MPG. Fortunately gas is cheap or i would be furious. they are wearing very nicely though with 50% more life (clear evidence they are not LRR, can't have it both way).

too bad they are still listed in the LRR tire sticky thread (probably only because of the name).

 

First off, older tires will have lower rolling resistance than new tires because the worn tread and harder rubber reduce tread squirm. Give it some time. Second, unless you're testing in controlled conditions, I wouldn't put much stock in "I was expecting XX mpg but I'm only getting XY mpg" assessments; mileage is affected by a tremendous variety of factors, and the effect of tires is just one small part.

 

....ditto on GY losing wet traction when the tread was still OK, my wife actually had a minor accident in the rain just 1-day before our appointment to install the Tire Rack tires. We went with the Conti True Contacts though. Our GY were the Assurance ComforTred an earlier version.

 

Tire Rack shows them as LRR.

 

I've put over 40k on my current PureContact tires now and I can say that my MPG has finally gone back up to what I used to have. I originally bought these tires because they have excellent reviews on its handling. I was never impressed with the OEM Bridgstones' dry or even more scary, wet, handling so that's why I replaced them even when they have more than 10k of tread left on them.

The Continentals have a 70k miles warranty and they still have a little less than half the tread left. Handling is excellent in both wet and dry and even lightly dusted snowy paths. One bad thing about these tires is that they get pretty noisy after about 30k miles of driving.

Tire that contributes excellent MPG is important but when you have 100-mile commutes every day, I'll take ones that have better ride and handling over MPG any day.

 

I have only two tire requirements: 51 psi sidewall pressure, and revs/mile to correct the speedometer and odometer to be <1% off. However, I am surprised the wheel rims were damaged.

The only way I could imagine that would be if the air wrench were set to 'torque impossible' and the technician crushed the alloy wheels at the hub. In which case, if there are cracks, the wheel rims would be unsafe. 'Shaved' metal would be bad but not necessarily a safety hazard. In either case, the lug nuts would be too tight to allow a human to change a flat tire. Take pictures and let the service company 'do the right thing.' Pictures are lawyer fodder.

The other thing I do is buy a 'life time alignment' service (mine is from Firestone but I understand Goodyear has one too.) Typically $100+, it is fair to have an alignment checked at least once a year. Share the report so we can see both the front and rear wheel alignment: toe and camber for each wheel.

Bob Wilson

 

Thanks,

We needed to understand:

The metal scratch is potentially a problem. My concern is small fractures that are not visible to the eye. Over time, metal salts will find these cracks and do their damage. Need to check the inside rims too (for piece of mind.)

In a perfect world, dye testing would reveal micro fractures. At a minimum, after the current repairs, a clear coat would keep corrosive road salts away from any fractures. Or just check them once a year.

GOOD LUCK!
Bob Wilson

 

I'm thinking they just relay the manufacturer's claims. They'll often accompany the spec. with the manufacturer's expression, for example "ECO", or "GreenX". There seems to a quite a gamut of LRR, and often tires that don't even claim to be LRR best the claimants. You have to be sceptical, consider the LRR claim, but research the heck out of it too.

 

Here is a simple explanation on why mileage always go down after putting in the new tires. New tire diameter is probably 1/2 to 3/4 of an inch larger ( more thread) than worn tires. Car computer assumes some constant tire diameter when calculating mpg. So new tire will give you larger distance covered vs old tire, with the same number of rotations. With the tire diameter of About 30 inches ( can't remember exactly) , that would correspond to ~ 2 mpg decrease provided everything else is equal.

Alex

 

Alex, everyone knows about the 2% mpg loss due to taller tread. throw in the extra tread squirm and softer new rubber and we have about 4% loss (consistent with your 2 mpg in a prius). this is what i expected. instead that i got about 15% loss (everything else was equal). furthermore, not much has changed 2 years and 35,000 miles later. explain that, please.

traction is good BTW, but not as greater over the OEM tires as i expected either. they really shine in tread longevity.

 

There's some question of what makes LRR tires LRR, but I'd say if a place/manufacturer advertises them as such, you might be able to file a complaint with the FTC.

 

The most fuel efficient tire in North America is and continues to be the following.
Michelin Energy Saver AS, 195x65x15. On my 2nd set with our 2010 Prius. Last fillup 55.6 mpg calculated. So far indicated for over 300 miles is a dash indicated 63 mpg, which is about 59.5 calculated. 65 to 70 thousand miles on a set...

 

I think that A/S is great tire but in areas with snow/ice that's where the rankings are not as good as say Conti True Contact

 

I looked at that with a spreadsheet, a while back. Comparing the stock 15" Prius tires, brand-new vs down-to-the-wear-bars, the revs per mile varies by a factor of 0.985, which means if you were getting 50 mpg with the new, under the same conditions with the worn tires you'd be getting 50.76 mpg.

 

Try again! The distance a loaded tire travels per revolution does not change in direct proportion to its change in unloaded diameter as it wears, as someone else explained in detail in another thread recently. Even IF it hypothetically did, and if we accept your 0.985 number, that only means if you were getting 50 apparent (uncorrected) mpg with the new and got the same actual mpg with the old, then the apparent mpg with the old would've been 50.76.

The main reason new tires yield worse fuel economy than otherwise identical worn ones is their higher rolling resistance, not the change in unloaded diameter.

 

I agree, was actually trying to say: even the theoretical difference in diameter is trivial.

 

I just replaced my Michelin A/S Energy savers with Michelin Defenders and yes I took a major hit. I'm guessing four to five mpg's and I can say I have less than 1,000 miles on them so I expected a hit. We'll see once I make sure my Scan Gauge is properly calibrated at my next fill up what the hit really is. I was seeing only around 46 mpg at 65 mpg yesterday with the AC on. Normal is closer to 51-52 with the AC. Anyway back to the subject new tires will always cost you upwards of 5% hit on fuel mileage. It may be anywhere between 5K and 10K miles before you start to see an improvement in fuel mileage.

From Cummins on the effects of a trucks tires on fuel economy. This information applies also to automobile tires on a smaller scale.

From page 16

Tread Depth and Pattern According to Bridgestone, the tire tread accounts for 60–70% of the tires’ rolling resistance

Not only do the tires differ in rolling resistance when new, but as the tread wears, the rolling resistance of the tire changes.
A 7/32 tread wear represents ~10% reduction in rolling resistance (5% better mpg) compared to a new tire.

Rib tires at all wheel positions will provide greatest fuel efficiency
Tread pattern is important be cause lugs have deeper tread (more rolling resistance) than ribs.
If we take a new ribbed tire as the standard, a new lugged tire is less fuel efficient by about 6%

A worn tire is about 7% more fuel efficient than a new tire.

Link to the Cummins Study on Truck fuel economy. If you get some time it is well worth the read.

http://cumminsengines.com/uploads/docs/cummins_secrets_of_better_fuel_economy.pdf