Looking for Tire recommendations for my 2020 Prime

I had my tires filled with N2... but with the same observation. I didn't have an accurate recording then, but the overall observation was similar. It made almost no difference. Nitrogen fill is the biggest scam in the tire industry. I would never pay for it, but I had a free service with the gas, so I gave it a try.

Besides, it does not matter why my tire psi fluctuates. The fact is it does fluctuate on daily bases, and I never had an alignment problem. So, the point is, that tire pressure changes are a normal variation of cars, at least for my cars, but that does not warrant a daily alignment correction.

 

Found this article: "http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73"
Somehow the link is not working but copy and paste url should work on a browser.

The results of the TireRack experiments were:

1. With an ambient temp change of 67° to 85° Fahrenheit (18F differential) and the direct sun hitting the tire, the tire pressure changed from 35 psi to a high of 40 psi.
2. With tire's flexing, a total 40 min of road driving condition increased the pressure by 4-5 psi.

Add those two together, if my tires see 30F temperature differential, and the car is parked in sun during high temp of the day, and I drive 20 miles or about 45 min on that tire, yeah, it is totally possible to see a 10 psi daily tire pressure fluctuation.

 

I guess this is as good a thread as any to throw out some questions. Just over 1K on the new PP, and it does indeed have much improved handling over my old Gen III. My car has the factory Bridgestone Ecopias, and they're not bad (car is much quieter than my Gen III, and has decent cornering) BUT I would love to have a stiffer sidewall. The question is how bad a hit does the economy/E-range take by going to say, H-rated tires? When I put V-rated on my Gen III I lost at least 3-4 mpg, maybe more. Do they make an H-rated tire that is low rolling resistance? Or that just a non-starter? Would like to hear some experience with those who've tried stiffer sidewall/better handling tires on the PP.
Interestingly, my winter wheels have Michelin X-Ice, and they actually corner somewhat better than the Ecopias, even though they're not rated H or V either. The Ecopias aren't terrible, btw, they just give a lot before they "take a set" which doesn't inspire confidence for making sudden adjustments, like swerving around a pothole. I miss the V-rated sure-footedness, but I don't want to lose a lot of E-range.

 

Probably not.

Consumer Reports also rated the T-speed-rated Firestone All Season (no other descriptions in the name, just All Season) excellent in rolling resistance. They didn't rate the Enasave, NanoEnergy, and Ecopia though.

 

All of them

 

Just found that the Ecopias are also offered in H rating - has anyone tried them?
https://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Ecopia+EP422+Plus&partnum=965HR5EP422PL&vehicleSearch=true&fromCompare1=yes&autoMake=Toyota&autoYear=2022&autoModel=Prius%20Prime&autoModClar=LE

 

Yes. The Ecopia 422 Plus sold in the US has three different versions. If you click on the Spec on the TireRack page you linked and look for all sizes, you will see there are three iterations of this tire. One made in Japan is the OEM version that comes with Prius or PP. The other two are aftermarket versions and either made in the USA (4 ribs) or made in Mexico (5 ribs) and they have different tread patterns. I have not tried aftermarket ones on my PP but had them on my Gen3 and also on the other car. I did not have them on the same car, so I can't make a direct comparison, but they were all very good in terms of efficiency. Two aftermarket versions are slightly less efficient primarily due to the weight of the tire being heavier than the OEM. 5 rib version has a higher max inflating pressure, so if you do overinflate that is a better choice. But as far as the ride and comfort go, in my experience, they were all not so plushy rides nor most quiet tires. Also, they do not do so well on icy or snowy roads. I didn't notice much difference in handling or performance but that is one of the areas I never pay much attention to. One thing is that aftermarket ones come with 70K miles tread warranty, but mine did not last anywhere close to it. However, that could be due to where and how I drive. I have not had any tire that actually lasted to the claimed tread warranty limit.

On my PPs (I had three), 2017 and current 2021 came with Dunlop Enasave. I really like this OEM tire. It is not the best tire for wet and snow, but it is excellent on dry pavement and has the best efficiency. On my 2020 PP, I had OEM Ecopia 422 Plus with 91S, I did not drive much on this tire, but it felt the same as the other two aftermarket 422plus tires I have used on other cars. I have not purchased a new set of tires on my PP yet. Buying a new car was cheaper than buying new tires for one thing. But on my other cars, I have had the same size 195/65R15 Conti TrueContact and Yokohama Avid Ascend. IMHO, they were better than Ecopia. Both are still available, I think in newer designs. Yoko Avid Ascend GT and LX, Conti TrueContact Tour, are all Eco focus (LRR) tires and come in a 91H rating.

From the TireRack site, you can filter the tires for H or above speed rating and also select Eco focus. There is only one V-rated LRR tire. Micheline CrossClimate. I would like to try it myself, but it is too expensive for my liking. If H-rated LRR is OK, then, certainly, there are plenty of choices for 91H rating tires (a total of 12 listed in TireRack).

 

Here is a web page from a retired tire engineer detailing speed ratings and how a cap ply to get at least an H rating is important to minimize the standing wave in the tire body as it rolls. Barry's Tire Tech Look on the sidewall that lists the tire plies for a single nylon ply or something similar under the tread...that's probably the cap ply under the tread to give the tire body more stability. Don't be surprised if the tire sidewall has only one or two plies of cord listed. That's how tires have been made for many years. (The V-speed rated tires on my SUV have 2 polyester plies in the sidewalls, and 2 polyester, 2 steel, and 2 polyamide plies in the tread.)

So...an H speed rating or better is important for more than just the speed you'll drive.

 

I've had two sets of the Bridgestone EP422 Plus tires on my Gen 3 Prius (the US made ones). Never had any problems with them, but the tread life could have been better. I'm going with Michelin Defenders this time as the current set of Bridgestones are down to 4/32" tread. Consumer Reports rated the Defenders the best for this sized tire. The OEM Dunlop Enasaves on my PP were good but tread life was short and I got some flats with them towards end of life. I currently have Yokohama Avid GTs on my PP. These seem like good tires but I don't know how many miles I'll get out of them.

 

Do you take TireRack's "eco-focus" check mark seriously? For example, nothing else, including Michelin itself, lists Michelin Crossclimate+ as having low rolling resistance.

 

Just checked it on Consumer Reports: Michelin Crossclimate 2, the successor to Michelin Crossclimate+ that claims 10% improvement in fuel economy over it, received a poor rating on rolling resistance. So much for TireRack's eco-focus designation. Simply ignore it altogether.

 

Nop. I don't take the whole notion of "LRR" seriously. I think it is mostly just a marketing gimmick. Some tires are lighter and maybe have less aggressive tread patterns and special rubber compounds which are supposed to give a boost to the fuel economy, and others have more aggressive tread patterns and are heavier and harder compounds that affect the fuel efficiency negatively. There is no industry standard for LRR. The manufacturers can call their tires LRR or Eco focus or whatever if a particular model of the tire has a better fuel efficiency attribute. The TireRack is just calling whatever the brand with environmentally conscious manufacturing attribute, the Eco focus. It may or may not have lower rolling resistance, per se.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=334

 

Europe is ahead of the US on this. Tires now have fuel-economy and sound-level, in addition to wet-, snow-, and snowy-hill-performance ratings as well:



Tyres | European Commission

 

The tire attributes are always some compromise. If one expects less rolling resistance then the traction is going to suffer. If one wants better tread life, then fuel economy is going to suffer. You just have to prioritize what is the more important attribute for you. I do read and use objective tire reviews and tire ratings for the process of selecting my own tire. But in the end, it boils down to my own very subjective preference and opinion. Since I can't buy and test all tires, I usually end up picking one that is affordable, available, and attributable (for my priority).

 

D you use Walmarts Douglas on a 3rd gen? How does it feel on ice, or in downpours? What's the noise like? And how long do they last? I love the price, and I'm worried about how safe they are.

 

Yup. I have said that in a number of posts

 

They're terrific. The treadwear on them is somewhere around 500 the temperature and traction are A, the 60 profile tires have a speed rating of V And they last longer than many others I've tried. We get downpours here in Florida and these things are great. If you have to deal with snow you can't get a 60 profile because it'll be sitting deeper in the snow and that sucks but we don't deal with snow here and I'm loving the 60 profile. Don't take my word for it Read the specs on the sidewall. Never trust someone else's opinion because when they overpay for something they'll tell you how awesome it is. Lamborghini Gallardo is a perfect example. The car is junk you can't get 10,000 mi without the clutch going bad

 

This would be the tread pattern to avoid if you like staying alive in the rain. The problem isn't unique to just this brand of tire. We are finding that this tread pattern is downright deadly in the rain no matter who makes a tire with this pattern. We've had this pattern on a Jeep and a Camaro and in both cases it cannot handle water. We are finding that longitudinal siping is the best for water. Stay far away from this tread pattern at all cost

 

You need to drive slowly through flooded sections. Hydrodynamic lift force is directly proportional to the speed, and no matter what tire you have, you will hydroplane beyond a certain speed. See the Stribeck curve, which is the fundamental curve of lubrication theory, below.

 

Sipes (thin slits molded or cut into the tread blocks) are always transverse, not longitudinal. Tire grooves can be longitudinal.

How deep was the directional tread that you say was poor in hydroplane conditions? Tread depth is critical to allow deep enough grooves for the water to drain away. The directional tread tires I've owned have been no better and no worse that others. My Bridgestone and Michelin snow tires have directional tread somewhat like that shown, and they've been great in both deep slush and deep water in heavy rains.

There is no industry standard for low rolling resistance tires. And, we put quite stiff & heavy Bridgestone DriveGuard run-flat tires on our Prime, and the battery endurance distance is about the same. I'd buy a similar tire again, hopefully an upgraded version that runs smoother and quieter. Don't compare the fuel consumption of old thin-tread tires with new deep-tread tires. The new tires will always cause more fuel consumption.

Douglas tires are a brand name that Goodyear puts on tires for Walmart. Goodyear (and their Kelly brand) is a major manufacturer of private label tires. That does not mean the tires are especially good or especially bad, but for Walmart they're probably cheaper construction with less tread life and other corners cut to keep the price down. I'd bet that identical tires are made by Goodyear with other brand names for other private label customers. For some drivers "good" tires are round, black, and not bald all the way across. For others "good" tires must have great traction, great handling, and usually long tread life, also smooth & quiet. I find myself in the latter group.