Those references are relative measures. And to expand upon that, a tire with higher tread-depth but lower tread-wear won't perform as well either. Factors like choice of when to replace or even how often to rotate come into play. Then of course, simply driving slower reduces risk rather substantially. If we were striving for the highest efficiency, there are poor choices available. If we were striving for the highest safety, there are excellent choices available. So, the best approach is to ask what the owner actually wants. What are they looking to improve? Some consider the factory tires a safety issue, others consider them just fine. Some of us just want to find the best balance of many performance aspects, as well as price. I wouldn't consider a 0.5/32 difference as big as that implies. The devil is always in the detail... EP422 = 10/32 Energy Saver A/S = 9.5/32
I'm sure some mountains just do not lend themselves to Prius MPG techniques, but this is not an all or none approach. If you manage 1/2 the mountain with good fuel economy you are that much ahead in the game. I drive over the continental divide every week in New Mexico. The posted speed limit is 70 mph, so I hit 70-75 mph by the start of the incline and then set the fuel pedal at the beginning of the power band. By the top of the mountain my speed has often slowed to ~ 50 mph. Since the road is lightly traveled and has a passing lane in each direction I do not bother or prevent a hazard to anybody. This technique handles all but a handful of places.
I'm basing my opinion on the needs of the person who asked the question and the large number of surveys/reviews I've read on the three tires in question. The ESAS is simply rated lower in snow traction than the other two tires. The EP422 offers the same tread wear warranty and the PureContact offers a longer warranty. For snow the ESAS is a poorer choice compared to the other two tires. For wet weather the EP422 is a poor choice. The PureContact is good in both but slightly less efficient. *shrug*
I looked over my ES A/S and there is no direction arrow. Also I checked the tread depth and I think it was 10/32 not 9.5/32. I'll check it again tonight to make sure. Maybe Michelin added the .5/32 to get a little more wear out of the tire ? If it is 10/32, that is the same depth as the defender.
A lot of tires tend to measure higher than their official rating. Also check that you have the T rated version.
They are the T rated ones. That I remember because the OEM Yokohama was a 89S and this was an 89T. Sure glad I'm safe up to 118 mph instead of 112 mph
After ~26k miles, I'm up for new tires for my 2010 (w/ 15" wheels). I live in Massachusetts, so we get hit with all seasons. Snow in the winter, but not as much as upstate NY; rain, but not as much as in the PNW. I started looking into tires a few months ago and I thought I had settled on the Ecopia (422 or 20? What's the difference?), but now I'm seeing a few more options. My tires are bald, which caused me to fail my inspection earlier today ( ), so I really need to get tires today or tomorrow, depending on how quickly they can get them in stock. My local BJ's (big box store like Costco) currently has a $70 discount on Michelin, and they're able to get the Energy Saver A/S, but it seems like it would be a bad choice for my local climate. If I search by tire size (EMetric 195/65/15R), they also have the Primacy MXV4 and Defender (both are in club). I don't see any Bridgestone or Continental tires when I search (P)195/65/R15, and it doesn't look like either of those companies are running promos right now. I'd say all-weather traction (i.e., safety) is the highest priority, with fuel economy and cornering/performance closely behind. What should I get?
For your needs I'd suggest the PureContact. They never run sales on this tire because it is already inexpensive compared to the Michelins. TireRack.com sells the 195.65/15 for $87! Continental PureContact with EcoPlus Technology
Shipping is about $45, and after installation, the price will probably be on par with the Primacy. Do you think the PureContact is a significantly better tire for my needs?
I do. It has better snow traction, is more fuel efficient and lasts longer. The Primacy MXV4 is a great tire and is more comfortable but if I had to choose for your conditions I would go with the PureContact. Its wet weather traction is in a class all its own.
How does the 15 inch PureContact on Prius compare with the OEM Yoks mpg and road noise? I'm getting down to the point where I need to start looking at tire replacement. I don't like to run the Prius on the snow here, since our road crews use so much salt. When we do take the Prius, it's only after the roads have dried and salt won't coat the car. In 2000, we decided to buy a used Saturn Wagon ('99) to sacrifice to the salt gods. The body won't rust away, but the metal underside bits are now probably on their last year, unfortunately! The old wagon rides on dedicated snow tires all Winter (aggressive Pirelli Winter Carving, second set) and has done a great job of getting me and my wife to work in the worst Maine Winter conditions without drama. One thing I have to note, definitely impressed and surprised at the amount of snow grip that the Yokohama Avids produce. A good friend uses his 2010 Prius all Winter on the OEM Avids, and I've driven this car to the ski areas. Was concerned at first, but they actually performed very well on snow covered roads, even though they were significantly worn by last season and are now down to the wear bars this fall! Will probably recommend that he replace his Avids with the PureContacts... but would like some feed back on this tire's noise level, since Prii are not well isolated from road rumble. He's going to purchase tires next week. Any input/comments on part or all of the above would be greatly appreciated.
The EP20 comes in very limited sizes, maybe just 195/65R15? It's good for RR, has tread pattern that looks identical to their Insignia SE200. The EP422 has different tread pattern, comes in a much greater range of sizes, various profiles. If I was looking for 195/65R15 I'd be inclined to go with the EP20, it's likely cheaper. It has decent wear, runs/tracks well. Get's a little noisy when worn. Personally I wouldn't consider snow capabilities of an all-season, switch to snows on separate rims, more-or-less 5 months of the year. I can attest to the EP20 being pretty much hopeless in snow, once the tread starts wearing down.
FWIW, the Energy Saver A/S need relatively high PSI to get the mileage... Our tire dealer put 36PSI in them (for the 205/60 R16 sized tire rated to 51PSi) and then we had a cold snap that reduced them to 35 cold PSI. Mileage dropped on our prius v 2 down from 51ish to 43ish MPG. After reading this thread, i just put them up to 44 front/42 rear and will see if that gives a better balance of comfort and MPG and especially braking distance. I wonder if there is a test of difference i braking distances at different PSI levels for similar LRR tire models?
Well, fwiw, found the answer to my question kind of... http://m.iopscience.iop.org/1742-6596/364/1/012014/pdf/1742-6596_364_1_012014.pdf Bottom line is there is a sweet spot for braking performance below max which most gearheads know... The report suggests 32PSI approx for best braking, but that negates the whole reason for the LRR tire. Then shows that roughly 38 PSI (2.5Bar) stopping distance increases 4 meters (~13 feet). The max in the report data goes to 3Bar or 43PSI roughly to show contact patch decrease at that pressure but doesnt give stopping distance info. Figure slightly less than linear degradation in braking above 38 PSI since the contact patch net difference in size (vs32psi) is less as psi increases to max pressure for the tire... And you'll never get to zero contact patch unless you have a flying DeLorean wih flux-capacitor! Anyhoo, I'm sure everyone was just as eager to hear this (not so) earth shattering news!
Your drop in mileage is likely as much due to the temperature drop as the associated tire pressure drop. The car monitors ambient temperature, and changes warm up behaviour, and will generally take longer (if ever) to get to fully warmed. 'Till then fuel economy will be less than optimum. Lower tire pressures contribute too, but...
I have a little over 700 miles on the new Energy Saver A/S P195/65R15 on my 2010 Prius, and have been very happy with the calculated MPG at 50.8 given the cold weather. Running tire pressure at 42/40 front/rear. Road noise is higher than I expected, and the noise really varies depending on the road surface. Traction and handling have been very good. Will be interesting to see MPG with warmer weather...
We have snow here and temps well below freezing now. The tires have proven a nice choice for handling that.
Wanted to post an update. Weather this week has been warmer here in Central Texas; between 40's and low 70's, and the calculated MPG on the last tank was 53.4 (56.1 on the computer). Driving was 50/50 city/highway. I attribute the MPG to the new tires (never got this MPG with the OEM Goodyear FuelMax with this type of driving/weather).
There's been mention here of new Pirelli Cinturato P7 All Season Plus. Available in 215/45R17 (and alternate) 205/50R17. It's described as LRR. Just to put it on the radar. Pirelli Cinturato P7 All Season Plus
