"Green" tires to be standard in Europe by 2012

[Piwoslaw]

This is based on another article from the eco-issue of Auto Motor i Sport (2/2009).

The European Union is reducing CO2 by setting limits for the automotive industry. In order to raise fuel efficiency (and lower CO2 emissions) the car companies will have to switch to "green" tires with lower rolling resistance. In fact, the EU has mandated that all new cars in Europe be sold with eco-tires in 2011, and all new aftermarket tires must have lower rr in 2012. To aid customers in choosing best tire, they (tires, not customers) will have tags that help compare their rolling resistance, grip and noise. The tags are similar to ones that can be found on all household appliances sold in Europe, stating their energy (and sometimes water) comsumption class. Unfortunately, which class the tire falls into will be solely up to the manufacturer. This shouldn't worry us with tires from well-known producers, such as Michelin whose been selling lrr tires since 1992, but could be a problem with cheap tires from China.

[JonnyG]

Is there going to be an exception in certain countries for winter tire use during certain months?

[brucey]

It's my understanding you can get low RR snow tires that perform excellent already. The Hakka R's come to mind.

[JonnyG]

Oh I didn't know that. I'll have to look into those for myself.

[Daox]

Are they using standardized testing for the tires now? Last I hear, Crr testing was completely up to the mfg and they all do it differently.

[tjts1]

Is there going to be an exception for track or autoX tires?

[Piwoslaw]

I think the testing is still up to the mfg, but there are some independent institutes that may check it (and EcoModders as well ). There will be more testing and checking as this starts to get more and more important.

I don't know anything about track or 4x4 tires.

I've noticed that most articles on low rr tires (including this one) comment that lower rr reduces grip and braking efficiency, but only once have I read that those are two different animals: Rolling resistance is mostly from the tire wall flexing, while grip depends mostly on the type of rubber used in the tread. Of course, tread pattern has an effect on both, and decreasing sidewall stiffness can improve grip while increasing rr. If a tire is reengineered to have a stiffer sidewall, good tread pattern and soft rubber tread (all in the right proportions), then it will have lower rr while retaining safety and handling parameters.

Or you can just pump your tires and drive slower

[CapriRacer]

Originally Posted by Piwoslaw

........I've noticed that most articles on low rr tires (including this one) comment that lower rr reduces grip and braking efficiency, but only once have I read that those are two different animals: Rolling resistance is mostly from the tire wall flexing, while grip depends mostly on the type of rubber used in the tread. Of course, tread pattern has an effect on both, and decreasing sidewall stiffness can improve grip while increasing rr. If a tire is reengineered to have a stiffer sidewall, good tread pattern and soft rubber tread (all in the right proportions), then it will have lower rr while retaining safety and handling parameters.

....

Sorry, but sidewall stiffness hardly enters the equation when it comes to RR.

RR is pretty much all about the tread compound - how much, what kind, how much deflection (basically inflation pressure). You just can't escape the Wear / Traction / RR triangle.

Barry's Tire Tech

[gone-ot]

...tire "hysteresis" is a function of rubber flexing upon contact with the road, then compressing under weight, then un-flexing upon release from the road.

...that's *why* an older, well worn tire has a lower rr value than does an identical brand new tire.

[rgathright]

Green tire regulations will mean more advances for us as well.