Tire (tyre) surveys from the EU
 

While looking for car safety, I found this UK web page with references to several European tire testing results:
Buying better tyres - Why Better Tyres | Campaign for Better Tyres

Some of the government and organizations reports include the following:

• rolling resistance
• wet braking
• dry braking
• aquaplaning
• wet handling
• dry handling

After nearly a decade of "noise" about the importance of tire rolling resistance measurements, the USA continues to fall behind. About four years ago, California tested just under 400 tires yet never published the list. Tire Rack writes 'this is important' fluff but again, fails to give any rolling resistance ranking by tire. Only Consumer Reports gives a tire rolling resistance score using their 5-value, scale ... no numbers. Heck, even our EPA has given more 'eyewash' than facts and data about tire rolling resistance.

Rather than curse the darkness, this web page is an index of EU tire (tyre) test listing brands and models. Now we may not have the same models but knowing who is doing a good job is a good, first step.

Bob Wilson

...OK, we know which 'brand' knows *how to* make LRR tires, but we still don't know which of their USA tires is good/better/best.

I have been thinking about the problem and it occurs to me that there will be a collection of various tires at HybridFest/GreenCarExpo in about eight weeks. Now if someone had a portable, tire tester, Madison would be an ideal place to test a collection of tires.

Bob Wilson

You mean this list?

http://www.energy.ca.gov/transportat...95%20MEANS.doc

Thank YOU!

Working from the URL, I found the transcripts, presentations and the associated spreadsheets:
http://www.energy.ca.gov/transportat...uments/#061009

I had given up on the California Energy Commission when I knew they had measured the tires but didn't include a published list. With the 'Governator' in charge and his approach to budgets, I figured he'd zeroed the money needed to report the findings.

Thanks,
Bob Wilson

Actually, I think the problem was one of intent. They intended to write a regulation to forbid the sale of tires with high RR values - and they found they couldn't. The physics involved is so complex that simple, easy to understand, easy to administer regulations would not work.

They also discovered that wear, traction, and RR are in a 3 way opposition of each other. That means that if they wanted only low RR tires, they would force people to either buy tires with low traction (Obviously a safety issue) or that wear rapidly (and what do you do with the additional scrap tires?) There was no good answer here.

Besides, the Federal Government (NHTSA) stepped in a started to write a regulation - and that would superceed anything done at the state level.

Lost me there. Why would LRR tires wear more rapidly? I would think they'd wear less rapidly: harder compounds, lower flex for less heat & friction, etc. And certainly I haven't noticed the Potenzas on the Insight wearing particularly fast. I think I replaced the rears (which AFAIK were original) at about 80-90K miles, and they're still looking good at 150K. The fronts do wear faster, but I think that has something with my habit of not braking much in the curves...

Engineering often comes down to making choices: good, fast, cheap, pick two of three. When I was tire shopping, I used Consumer Reports:
http://hiwaay.net/~bzwilson/prius/pri_tire_200.jpg

Since we live in North Alabama, braking on ice is rare as the whole area shuts down. As for wet braking, our roads are exceptionally slippery when it rains and it really doesn't matter what tires are on the car. So I went with Sumitomo T4s which happened to be Toyota's replacement tire. They also are sidewall rated at 51 psi.

I was aware the NHTSA was doing something in this area. But the NHTSA effort looked more like an attempt to pre-empt the California regulations and delay rolling resistance ratings one more time. The tire manufacturers are doing everything they can to block it which doesn't make a lick of sense.

Bob Wilson

Actually, the tire manufacturers are doing what they can to support the NHTSA proposal, but NHTSA had a hiccup.

They wanted to do RR Force, which makes larger tires look worse for RR. but if RRC (Rolling Resistance Coefficient is used larger tires are better - which is the way most folks would look at it. The GSA asked NHTSA to reconsider - and that was a year ago. In the meantimm, NHTSA has gotten tied up with a lot of Toyota issues!

Was "RR Force" for the same load or at the tire maximum load?

I want "RR Force" but realize it is a function of load. If "RRC" can be multiplied by the load to give "RR Force," I would be satisfied. I need "RR Force" adjusted for current vehicle weight to calculate the energy loss.

Bob Wilson