Yokohama Avid Envigor and Gas Milease Drop

Yeah it does, but nothing dramatic. Overfill is bad for other reasons though, so best to make sure they never fill it more than 1/4" over.

What happens with overfill is that the bottom of the cranks start to splash into the oil and it causes energy loss. Actually it's only increased "windage" on the crank at first but eventually the crank really splashes into the sump oil if it's high enough. A lot of people like to run their oil about 1/8" to 1/4" below the top mark (on the dipstick) for minimum losses, but seriously it's only a tiny gain, maybe one MPG extra by running at -1/8" compared to +1/8".

Wow you know you're hanging with the real hyper-miling freaks when you start obsessing over your oil level to the nearest 1/8" inch. LOL

 

Not disputing what others estimate to be a small MPG change due to overfill of oil. I am reporting my experience. My oil was overfilled by about 1/2" over max indicator on dipstick. I noticed a more sluggish accelerator feel and slower response time (engine responded slower to driver input) The dealer and a pep boys tech both told me that the effect would be minor and that they have had instances where their "non hybrid" was overfilled and they noticed no change in performance.
My opinion: perhaps because the prius engine is running or tries to run at lowest rpm's possible, I believe that it does affect performance and FE much more than a traditional auto. Once I removed the additional oil, the performance and FE went back to normal. The mpg went back to 57 as opposed to 52 with the overfill. Check your oil level, it is easy to do.
Good Luck

 

Yep. I think we always knew it was the tires.

I could be, I've never had a 1/2" overfill. The maximum that mine has ever been overfilled was about 1/4" and it seemed to only give a small reduction in mpg. The response is not necessarily linear. At 1/2" you might get some serious splashing while at 1/4" perhaps it's just a bit of energy going into waves and ripples from the windage. Who knows?

 

Just wondering: Could the drop in MPG be attributed to the error in the speedometer/odometer because of the change to the diameter of the tire? For example, if one was basing their previous MPG, using their normal speeds, (say at 65 mph), their "true" speed would be operating at some speed above 65, (or any other speed), due to the larger diameter wheel having to turn faster. This could be checked out using a GPS.

My theory would be if they operated at some speed less than "indicated" (on the speedometer), their MPG would be the same or greater than running on the smaller rims.

I inquired about getting our new Prius with the larger rims, but the salesman said we wouldn't be happy as the speedometer/odometer would be off. One would think this car, being so technically advanced, there would be a way to adjust the speedometer/odometer to reflect a larger wheel.

 

That's a huge drop in mpg with the change of tires. What's the secret behind the OEM versions ?

 

Can't comment about the different brands of tyres/tires you have in the US but I found immediate loss of mpg's when non low rolling resistance tyres were fitted to my car about a year ago.

I had them changed back to LLR tyres and the economy immediately shot back up to what it previously was. I posted a thread about this situation back then.

I have had two new tyres on the back of my car in the last few days with NO noticeable loss in mpg's. Both the new tyres are LLR Bridgestone Ecopia's which were stock on the car at new.

 

aginzu, thank you very much for posting the detailed review. That will be very helpful to the PC community and myself. Please report back after they are broke in. It will be great to see how the tires change or not.

 

So I guess that means when I'm getting 60 MPG on my AVID ENVigors I'd be getting even a couple of MPG better on lower rolling resistance tires. But then I'd be out the higher cost of the other tires (average LRR tire is something like $25-$50 more per tire vs the AVID ENVigor)

and fwiw I run higher tire pressure. I was doing 42/40 on the OEM Integrity but I'm doing more like 48/45 on the AVID ENVigors. Having a 51 PSI max sidewall rating gives me the confidence to push it a little higher.

I can see getting LRR tires for those who drive long commutes or a taxi or some other high miles per day usage. Myself I'm more likely to replace a set of tires due to dry rot than I am due to running out of tread so I buy based on traction/handling and cost per tire and that pushes me towards non LRR tires.

Oh, and that's not to mention when a tire manufacturer makes the same tire LRR at 195/60/15 but not LRR at 185/65/15 or any other workable size like the Kumho Solus KH16. There are plenty of other tires that only do LRR in one or two sizes out of dozens.

I'd love to know the actual RR of all the tires on my short list:

General Altimax HP
Yokohama AVID ENVigor
Hankook Optimo H727

But without that info I'm just going to assume that for people driving under 10,000 miles per year can safely choose a better handling tire for less cost than the LRR option and not worry about the difference in RR.

 

It's a Gen II 2005 with 15" rims so I'm running 185/65/15 in the mid 40s PSI wise. I use a 3 PSI diff from front to back when I'm running in the 40s going by the % diff of 35/33.

I also buy 100% gasoline (no ethanol aka E0) either at a gas station about a mile from the work end of the trip. Nearest 100% gas to my house is more than 6 miles away (not on the way to anything I do).

The commute to/from right now is ~16 miles each way with about 1/3 of that distance done at 65 MPH, about a 1/3 done at 45 MPH, and about 1/3 done under that (both ends of the trip involve either neighborhood or parking lot driving at lower speeds plus the feeder/backroads)

I used to try to keep the speed at 55 MPH on the highway portion but found out that I was getting better mileage at the faster speed (there are numerous downhill/uphill sections on the highway that push the Prius to very low MPG uphill at lower speeds). Maintaining momentum helped. But if I want every last drop of MPG I "drive with load" and do more like 70 MPH downhill and 50 MPH uphill and do the speed limit on the relatively flat portions.

It's also been low 70s to upper 80s on these runs. I use the AC when it gets too hot but the car is in a garage at home so AC doesn't stay on the whole trip.

OH, and the 60+ MPG I'm seeing is MFD (on the screen) so my tires being 850 Revs per mile + the over-inflation might be off slightly vs actual fuel consumption. I don't think it's off enough to invalidate the comparison though.

So short list is:

High PSI tire inflation
100% Gas
decent weather
a route that forces some low speed driving (not my choice)

 

Dhanson865, Your post is a bit confusing. Your state that LRR tires cost $25-$50 more thank the Avids which is only correct for a couple of tires and untrue for the majority. Your also make the assumption that people replace perfectly good tires with new LRR tires just to save a few mpg.

I 'mcurious what brought about this post.

 

Just replying to the content of the thread between aginzu's posts in general in this thread and your post where you say

"I still don't understand why people purchase non-LRR tires for a replacement tire."

Now you think that $25-$50 a tire increase isn't valid so let me pull some comparisons from tirerack (you might get them cheaper locally but I'm just pulling from tirerack to have apples to apples comparison since not all dealers carry all tires)

The first tire I considered for my car was the Altimax HP. I could use 195/60R15 at 850 RPM although the 185/65/15 is OK at 843 RPM. One is $70 a tire, the other is $71, no bid difference there.

I then saw the AVID ENVigor (this was early in the life of that tire when there were very few reviews of the ENVigor on tirerack) but the 185/65/15 is now $80 a tire. At the time the price difference wasn't as noticable to me, maybe I got a good deal or maybe the prices have shifted slightly in the last year or two. And just like aginzu I saw the "All-New Silica Compound. Delivers ultra-low rolling resistance for increased fuel efficiency, without sacrificing treadlife, comfort or grip on dry, wet or snow-covered roads." mention and figured I'd give it a go over the slightly cheaper Altimax HP.

Now the way I chose at the time that we can reproduce today was to go to tirerack.com and search for 185/65/15, deselect all summer tires, deselect all snow tires, make sure light truck tires weren't in the mix (not an issue)

At that point the top rated tires are (note the results now are different than the search I did back then)

Goodyear Assurance ConforTred Touring (not to be confused with the non touring ConforTred)

Michelin Energy Saver A/S
Michelin Harmony
Pirelli P4 Four Seasons
General Alimax HP
Kumho Ecsta LX Platinum
Yokohama AVID ENVigor

Apparently the AVID ENVigor has dropped a bit as it used to be rated higher than the Alimax HP.

Next I'd compare the tires looking at the Customer Survey Data and toss out the ones with poor wet traction or poor dry traction. None of these would get taken out for that.

I also tossed the ones without a 51 PSI sidewall rating. Which might have colored the price difference a bit.

So if I were making the choice at this point I'd go for the Altimax HP based on price at $70 a tire but I'd call around to see if my 2nd or 3rd choice tire could match that price.

without going through all the calls the sorted by price options would be

Ecsta LX Platinum 185/65/15 $70
Altimax HP 185/65/15 $71
AVID ENVigor 185/65/15 $80
Assurance ConforTred Touring 185/65/15 $91
Assurance ConforTred Touring 205/60R15 $111

So why the $111 for the ConforTred 205/60R15 at 846 RPM. It's only 1 pound more than the 185/65/15 at 855 RPM. For that 1 pound difference you gain more max load, higher speed rating, and an extra 32nd of tread. Hmm, maybe not worth $20 a tire.

Why not the Kumho Ecsta LX Platinum? I do not know, it never popped out to me as a serious choice. Am I overlooking a diamond in the rough?

So are any of the 4 that made it through the filters LRR? No, the only one rated high on the Customer Survey Data that is LRR is

Michelin Energy Saver A/S at $104 a tire.

So comparing $70 a tire to $104 a tire it's over $30 a tire which is roughly in the $25-$50 range I mentioned.

The price difference is more pronounced when you make the comparison in 16" or 17" tires which was in my head from discussions from another thread on PriusChat.

The other LRR tire I looked at was the Goodyear Assurance Fuel Max but I didn't like it's lower traction numbers in the Customer Survey Data. If I wanted to consider it I'd go look for pricing on

Fuel Max 185/65/15 855 RPM $86
Fuel Max 195/65/15 836 RPM $99
Fuel Max 205/60/15 847 RPM $95

and I'd take the 205/60/15 as the wider tire might handle better and the RPM are almost dead on to what I think the correct RPM would be. Assuming it was only a few $ a tire more than the 185/65/15 I'd go for the 205/60/15 in this case. Either way it's more expensive than the Alimax HP for less traction.

The statement that confused you was that to get as good of a tire with LRR I'd have to pay more. I can get a similarly priced tire with LRR and make a trade off in traction for the LRR. That isn't what I want to do.

Since that purchase I've gotten used to the concept of revs per mile and navigating the tirerack site better. I'd now consider going to the categories and sorting by traction type and looking for the RPM I need in 15". For example
Consumer Survey Results By Category

Where the top 3 tires are

Firestone Precision Sport
Michelin Pilot Exalto A/S
Yokohama AVID ENVigor (H&V)

Consumer Survey Results By Category
If you sort it by dry traction you get

Michelin Pilot Exalto A/S
Yokohama AVID ENVigor (H&V)

and the firestone drops to 5th place.

We've already covered the AVID ENVigor, the Firestone is only $68 a tire but is noisy and has poor treadwear in addition to the lesser dry traction, the Pilot Exalo A/S I'd love to have in 205/60/15 at 850 RPM but they are $104 a tire.

There are more categories, I've done the sorts in several I'm not covering here to consider tires.

I hope that helps you through the though processes. I'm not saying the AVID ENVigor is the best tire for the Prius. I'm not even saying it's the tire I'd buy right now if I looked again (it might be the Hankook Optimo H727 at $74 a tire even though it's a 44 psi max sidewall marking or I might fall back to the Altimax HP which I've used on another car if getting the Hankook proved problematic for any reason)

Heck if you want to cry foul at me taking tirerack customer survey data seriously go for it. I'll listen, but that was and is currently a part of my decision process.

 

All other logic aside there is an error in this statement that F8L wondered about.

I consider the AVID ENVigor to be above average so the apples to apples statement should have been

"a comparable LRR tire is something like $25-$50 more per tire vs the AVID ENVigor"

I had a small brain fart there and messed up my comparative statement. I figured that out halfway through writing the mammoth post above but figured I might as well flesh it out so I can compare pricing data some months/years down the road.

 

I'm not calling foul, my friend. I know your have a mind for critical analysis and I just wanted to understand how your came to your conclusion. When your start adding in numerous filters like your did then of course other low priced tires will be excluded. Some people may choose to filter for different parameters and come to different conclusions. I'm just happy to see you doing your homework like each of us should do when choosing a new tire.

 

Since fall is upon us and winter is not far behind ,anyone have comments on LRR tires in snow, slush and ice compared to all season tires?