1. Fuel savings potential from low rolling- resistance tires Axel Friedrich Umweltbundesamt (UBA) Germany

2. Contribution of Tire to Fuel Economy
Historical Trends
ENERGY
DERIVED
FROM FUEL
ROLLING LOSSES + VEHICLE LOSSES + STAND-BY LOSSES
AERODYNAMICS: IMPROVING
INERTIA: CAR WEIGHTS AT MAXIMUM ?
TIRE ROLLING RESISTANCE
RELATIVE IMPORTANCE INCREASING

3. Test Populations (Car Tyres)
  12 sets of summer tyres of size category
175/70 R13 82T
12 sets of winter tyres of size category
175/70 R13 82Q M&S
12 sets of summer tyres of size category
195/65 R15 91V
 12 sets of winter tyres of size category
195/65 R15 91H M&S
The measurements were carried out in 1997/1998 by the Tyre/Wheel Test Center of TÜV Automotive GmbH
under contract to theUmweltbundesamt.

4. Test Populations (HDV Tyres)
4 sets of summer tyres of size category (light truck, delivery transport)  225/70 R15C
5 sets of steered-wheel tyres of size category (medium-sized truck,) /75 R17,5
5 sets of drive-wheel tyres of size category (medium-sized truck,) /75 R17,5
4 sets of steered-wheel tyres of size category (bus, municipal transport) 275/70 R22,5
4 sets of drive-wheel tyres of size category (bus, municipal transport ) /70 R22,5
5 sets of steered-wheel tyres of size category (heavy truck,) /80 R22,5
5 sets of drive-wheel tyres of size category (heavy truck,) /80 R22,5
The measurements were carried out between March and June 2000 by the Tyre/Wheel Test Center of TÜV Automotive under contract to theUmweltbundesamt.

5. Measurement Procedures
    Tyre/road noise
EU Directive 92/23/EEC
Rolling-resistance coefficient cR
ISO (ISO 9948)
  Wet braking behaviour
brake distance on a wet road
size categories 17.5” and 22.5”:
braking trailer with anti-lock braking system
  size category 15”:
commercial vehicles

7. Relation between rolling resistance and noise emission
48 car tyre types
(coast-by level measured according to EU Directive 92/23/EEC,
rolling resistance measured according to ISO 8767)
1,5
summer tyres
1,4
winter tyres
1,3
limit ecolabel
1,2
winter tyres
1,1
limit ecolabel
summer tyres 1
0,9
limit ecolabel
0,8
"Blue Angel"
0,7 66 68 70 72 74 76

8. "Blue Angel" Ecolabel for Low-noise and Fuel-saving Tyres (RAL-UZ 89)
Criteria (car tyres) -
coast-by level
<= 72 dB(A)
(92/23/EEC) -
rolling-resistance coefficient:
Summer tyres: <= 1.1%
(ISO 8767)
Winter tyres: <= 1.2% -
weight:
depending on tyre size: kg -
lifetime:
>= 400 (UTQG Test, Standards Testing
Laboratories, Inc. (STL),
San Angelo/Texas
- wet braking behaviour
at least average
properties regarding
- aquaplaning behaviour
state of the art

11. Influence of Compounds
Ultimate:
Single compound tire
Low RR compound ==> -52%
Special low RR compound line-up

12. Balance of Properties Wet Performance Silica Carbon Black
Using silica in treads enables to go beyond the trade off in wet grip and rolling resistance or fuel economy experienced so far with carbon Black. Compared to carbon black, It is indeed possible to improve wet without loosing in fuel economy or the other way around, fuel economy can be substantially improved at similar wet grip.
Silica definitely leads to new tire performance levels..
Carbon Black
Rolling Resistance Rating
Source: Goodyear

13. Rolling Resistance of Drive Axle Tires

14. Rolling Resistance steering axle tires

15. Exploring the Rolling Resistance Limits
Current Baseline 100
Source: Goodyear

16. Potential of Fuel Saving by low rolling Resistance Tires
30% reduction of the rolling resistance reduces the fuel consumption :
city driving: %
extra urban driving ( 70 to 89 km/h ) %
autobahn driving ( 120 km/h ): 2- 3%

17. Conclusion
The measuring results obtained show that the EU limit values for tire noise emissions are too high to bring about advances in the state of the art. Steps should be initiated to lower the limit values as soon as possible. 
Since no significant conflict of aims was found to exist between tyre/road noise levels or rolling resistance and the wet braking behaviour, binding restrictions throughout the EU should be introduced simultaneously to control the rolling resistance of tyres for heavy-duty vehicles and passenger cars and wet braking behaviour as well. 
In case of tires for heavy-duty vehicles, TÜV Automotive GmbH has stated that if, for example, tyres with optimised rolling resistance are used in road haulage, this will lead to a decrease in fuel consumption of between 4% and 12%, depending on route profile, speed, regularity of the speed, and vehicle aerodynamics.

20. www.umweltbundesamt.de axel.friedrich@uba.de