My MPG Results With Three Different Tires

oh hell, let's just say we didn't like the look of them....

 

You quoted me speaking about 2 different tires. The 2005 OE Integrity and the 2012 OE AVID S33D. The Integritys were beyond unsafe at below 4/32. The S33D was brand new but I deemed them unsafe for my conditions. Tramlining in bad weather can lead to a white-knuckle drive.

 

independent of tires, do you find tramlining more pronounced on the 2012 vs the 2005?

 

I do.

 

would make sense to me given the electric steering...less feel to begin with. The steering feel, or lack of, is taking some time for my wife to get used to, the MB had wide, low profile 19" tires(and hydraulic steering). To her the prius feels very light in the steering wheel, and grooves in the road obviously give the "feeling" of instability. in reality I doubt there's a real difference in grip between the two cars. or that she would notice a difference in two different sets of 15" tires.

 

The grip in the S33D was fine IMO. It was just that the car wandered around the highway (grooved cement sections) way to much. This still happens with my new Ascends but not as much. TheCritic's car does it with the Energy Saver A/S as well but even less than my car.

Larger wheels/tires (assuming proper plus sizing) tend to tighten up the streering. When I swap from 15s to 17s on the GenII the steering felt much tighter and the airy feeling is much reduced. Handling overall is MUCH improved as well. The GenII feels really wishy washy compared to the GenIII when using 15" wheels. It's unfortunate that the GenII loses so much mpg with 17" or larger wheels.

 

My OEM Goodyears are Assurances, not Integritys. I could be mistaken, but I don't think I posted anything about sudden braking with them in the rain in this forum because the incidents happened only a few weeks ago and I don't come to this forum often. Perhaps you are thinking about somebody else.

 

The "data" in the OP is of relatively little use. Since his car is a 2011, it covers about a year and a half in three segments. Hence different seasons, which can have an effect even in CA where he is based (temps/AC usage, rain, winds, etc). Also no info re whether his driving travel patterns changed, or his driving speeds or "style". Most telling, the mpg's he's getting are under EPA even on the OEM's: 44mpg vs 50mpg, >10%. It's relatively easy to get 55mpg from the Gen-III* and there are folks who are at >60mpg. I've been averaging just under 60mpg (calculated) winter and 62-63mpg summer. If we're worrying about mpg effects of a tire, we'd get better info from a car being driven efficiently.

A different and far more scientific approach was used in a post on InsightCentral a few years ago. Two guys with different tires, one of them OEM, arranged to meet on a straight level stretch of roadway several miles long. They made a series of runs at different constant speeds, each speed in both directions to try to zero out wind effects. They used the display tripmeters to record mpg's. Then they swapped wheels and repeated all the runs. They noted temp, wind speed and direction, tire pressures. Both cars were fully warmed up before the runs began.

That's a better way to get a meaningful comparison. It eliminates variations in "how the car is driven" and weather, trip length, and other factors. Unfortunately it does NOT eliminate variation due to whether the tires are fully broken in.

* my GF, who rarely drives the Prius, nailed an average of ca 62mpg (65.0mpg on the display) over the 140 mile trip from Boston to here last Thursday.

 

Of course people have the constitutional right to be inconsiderate, rude and obnoxious. It's under freedom of expression.

 

We were defined as tree huggers by the neighbor when we had an '07 Prius . They also had a few other choice words for us on other occasions . Usually when they had been drinking , which was most of the time . Nothing worse than a mean outspoken drinker . So much for being united .

 

The situation is complicated:

(1) Of the 7 gallons of crude oil needed to produce each tire (RMA: Rubber FAQs ), 2 gallons represents the energy needed for manufacturing, the remaining 5 gallons is refinery "feedstock" which provides raw materials for synthetic rubber.

(2) Synthetic rubber is made by polymerizing butadiene and styrene, both of which are byproducts from refining crude oil. Which means that we will ALSO get other products (such as gasoline and diesel) from that same 5 gallons of crude?? If I understand their statistic correctly.

(3) The same article says that 30% of rubber manufactured is natural rubber (no oil needed for raw materials) but apparently synthetic and natural rubber are both used in tires. The article suggests that synthetic rubber predominates because it's available in many formulations each with different properties, whereas natural rubber is a single formulation.

(4) The recipe for tire rubber given here
[ame=http://en.wikipedia.org/wiki/Tire_manufacturing]Tire manufacturing - Wikipedia, the free encyclopedia[/ame]
lists "oil" as the final additive (3.5 kg per 159 kg, or about 2%). THIS, not the feedstock crude, is apparently the oil that can be replaced by sunflower or orange oils in these eco tires. Sunflower oil is unlikely to contain enough styrene and butadiene for it to replace crude oil as a source for them.

(5) Sunflower or orange oil is used only in the tread, which is just one part of a tire (see Wiki article and Primacy MXM4 | Michelin Tires )

(6) Likewise, Bridgestone uses recycled rubber only at 5%, and only in the tread:
"Recycled Ground Rubber
Made from ground-up post consumer tires, it contributes to 5% of the tread compound."
(Bridgestone Tires: Ecopia EP422 (eco))

Every bit helps, of course, but some of the manufacturer's claims can be misleading.

 

We all know that manufactures will put their best foot forward and make it appear cleaner than it really is. I still applaud them for trying and in cases like Yokohama they actually do other things to assist reducing their negative impact on the environment. The are in the process of planting 180,000? trees and they are winning awards for green shipping and such. I'd rather support a company like that than one who doesn't even attempt green-washing.

 

Lots of rain, highway and surface streets, the A33's have been fine. You folks must have some demanding autobahn driving for all these F1 tire issues. Car just drives.

 

The Integrity tires that came with my 2006 were so bad that I gave them away before the first winter (to someone that lived in sunny southern California). They were really bad in rain. And judging by how they worked on other Prius in the area, they were impossible in snow.

Tom

 

I assume you mean the S33D?

Do you have grooved concrete highway/freeway surfaces? That is where we have the problem. Regular asphalt is fine. Unfortunately i have have 3 long sections of road that are grooved concrete on my 47mileone-way commute.

 

I had similar results when in 2007 I purchased a set of Michelin Energy Saver AS tire, 195.65.15, at Costco which replaced the factory Yoko Avid tires, which had about 11,000 miles on them and were inflated to 44 PSI in all four tires which is max sidewall pressure.

With the new, not broken in Energy Saver AS, the same size at the Yoko Avid, and 44 PSI in all four tires, again max sidewall pressure, I noticed an immediate 2-3 mpg more than the Yoko Avid tires.

I put nearly 70,000 miles on the Energy Saver and now on my second set, I had a set of Ecopia EP422 tires for a month and returned them back to Costco during the money back guarantee period and had them replace with the Energy Saver AS. The EP 422 were at least 2-4 mpg less than the Energy Saver AS and at high
speed would wander, 65 + mph, the Energy Saver tract straight and true with no wandering....

 

Most of the Michelin A/S testing was during the tyre break-in period, suggesting it's results are under reported compared to the others. If I did not have a winter climate I would pick the A/S hands down.

 

Michelin Energy Savers are $96 each at Discount Tire. And you get a $70 gift card.

 

I have the stock Yoko's on mine. In 16 months and 40k miles, I'm looking at new tires, I have tread left, and they are equal all around. I'm in socal and we do get rain. I drive fwy and streets for 90 miles a day. I 'm just looking for the right set of tires.