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-   -   "Green" tires to be standard in Europe by 2012 (https://ecomodder.com/forum/showthread.php/green-tires-standard-europe-2012-a-11350.html)

Piwoslaw 12-07-2009 07:55 AM

"Green" tires to be standard in Europe by 2012
 
1 Attachment(s)
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.

http://ecomodder.com/forum/attachmen...9&d=1260190382

JonnyG 12-07-2009 11:13 AM

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

brucey 12-07-2009 01:41 PM

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

JonnyG 12-07-2009 01:45 PM

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

Daox 12-07-2009 01:46 PM

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 12-07-2009 07:32 PM

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

Piwoslaw 12-08-2009 01:03 AM

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 12-08-2009 06:38 AM

Quote:

Originally Posted by Piwoslaw (Post 145689)
........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 12-08-2009 09:06 AM

...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 12-08-2009 10:31 AM

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

CapriRacer 12-09-2009 06:06 AM

Quote:

Originally Posted by Old Tele man (Post 145726)
...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.

Hysteresis is the amount of heat generated for a unit volume of rubber doing a unit of flexing. Think of it as internal friction.

And since there is less rubber in a worn tire, that's why worn tires have lower RR than new tires - everything else being equal.

gone-ot 12-09-2009 09:00 AM

Quote:

Originally Posted by CapriRacer (Post 146009)
Hysteresis is the amount of heat generated for a unit volume of rubber doing a unit of flexing. Think of it as internal friction.

And since there is less rubber in a worn tire, that's why worn tires have lower RR than new tires - everything else being equal.

...heat is a byproduct of hysteresis, not the other way around, because hysteresis is the "lagging" of stored energy behind its causing force.

...examples of hysteresis are: tires, transformers, magnetic recording, magnetic amplifiers.

...just about anything that deforms but doesn't exactly return to its pre-deformation characteristics, ie: less than 100% energy IN to energy OUT ratio...with some manner of intermediate energy "storage."

CapriRacer 12-09-2009 11:31 AM

Ok, OK, but we do agree that it's the amount of rubber (and not the hysteresis) that causes the change in RR between new and worn tires, right?

Piwoslaw 12-09-2009 04:03 PM

Quote:

Originally Posted by CapriRacer (Post 145709)
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

Thanks for straightening that out for me:)

Quote:

Originally Posted by Old Tele man (Post 145726)
...that's *why* an older, well worn tire has a lower rr value than does an identical brand new tire.

I thought that was because an old tire is smooth, while a new one has a more "knobby" tread, like a mountain bike tire.

gone-ot 12-09-2009 05:37 PM

...when a rubber knobby is bent over, it absorbs energy, but when it's released from being bent over, not all of the energy is returned as "springy-ness" in the rubber, but rather is wasted as heat.

...less rubber to absorbe energy = less energy stored, and thus less energy not being returned and ending up as wasted heat.

...some of the newer "tread" designs incorporate "deflection bumpers" in between the rubber block pieces to lower rubber-on-rubber contact which is purely "heat-generating."

...here's what Consumers Report says: "...As tires wear out, you’ll likely see improved fuel economy since the tires will have less rolling resistance as the tread (mass) is removed from the tire. Installing new tires, identical in brand and model as those removed, and you likely see a reduction in your fuel economy."


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