Overview Of Transport Canada’s Light Duty Vehicle (LDV) Tire Investigation And Planned Testing Of Class 8 Heavy Duty Vehicle (HDV) Tires In Winter Conditions

2012 Tire Technology Expo, Cologne, Germany
February 14, 2012

Overview

  1. ecoTECHNOLOGY for Vehicles II Program (eTV II)
  2. Background – Tire Labelling
  3. Part 1 – eTV Light Duty Vehicle (LDV) Tire Investigation
  4. Part 2 – eTV II Heavy Duty Vehicle (HDV) Tire Investigation 
  5. Moving Forward

1. ecoTECHNOLOGY for Vehicles II Program

  • The ecoTECHNOLOGY for Vehicles II (eTV II) Program supports Transport Canada (TC)'s strategic objective to develop a safe and environmentally responsible transportation system. Supports a proactive and integrated approach to address environmental benefits and potential safety risks of advanced transportation technologies.
  • The initiative tests, evaluates and provides expert technical information on the environmental and safety performance of advanced light-duty vehicle (LDV) and heavy-duty vehicle (HDV) technologies.
  • The program builds upon the program delivery experience and technical capacity established under the predecessor ecoTECHNOLOGY for Vehicles Program (2007-2011).
  • Technical findings from the program:
    • guide the proactive development of new or revised safety regulations, standards, codes and guidelines;
    • support the development of non-regulatory industry codes and standards that anchor the market and industry efforts to integrate new vehicle technologies; and,
    • help inform the development of future vehicle emissions regulations.

2. Background – Tire Labelling Programs

  • The European Union (EU) regulation 661/2009 will set mandatory rolling resistance of 12 kg/t for all passenger car tires and EU regulation 1222/2009 will have mandatory consumer information for tires produced after July 2012.
  • The U.S. National Highway Traffic Safety Administration (NHTSA) issued a proposed regulation in June 2009 that included rating systems for rolling resistance, wet traction and treadwear.
  • Canada is also considering implementing a tire program to promote the use of fuel efficient tires.

The label on the left was proposed by the EU commission in 2008 and comes into effect in 2012. The label rates the fuel consumption, wet grip and noise characteristics of a tire. The two labels on the right show were proposed by NHTSA – one label shows a tire’s fuel consumption, wet traction, and tread wear rating out of 100, and the other label shows a tire’s traction, tread wear and fuel efficiency using a 5-star rating system.
EU Tire Label 2012


NHTSA Proposed Rating System and Rubber Manufacturers Association Alternative

3. Part 1 –Light Duty Vehicle (LDV) Low Rolling Resistance (LRR) Tire Investigation

Objectives

  • In 2009-2010, as part of the program's mandate to test and evaluate emerging advanced vehicle technologies, eTV conducted a preliminary investigation of 25 light-duty vehicle tire models (including 4 winter tire models) to:
    • evaluate whether rolling resistance coefficients can be used to compare the environmental benefits of tires;
    • estimate the extent to which rolling resistance can affect fuel consumption;
    • investigate whether rolling resistance has an impact on dry braking distances;
    • compare coast down data to rolling resistance values; and, assess whether there is a relationship between Uniform Tire Quality Gradient (UTQG) ratings for traction and treadwear and rolling resistance coefficients.

3. Part 1 – Light-Duty Vehicle (LDV) LRR Tire Project

Test Methodology

  • Testing was divided into two phases:
    • Phase #1 – Laboratory testing (rolling resistance coefficients).
      • Steady speed (standard reference conditions & special conditions).
      • Coast down (standard reference conditions & special conditions).
      • Standard mean equivalent rolling force (over driving cycle at standard reference conditions).
    • Phase #2 – Dynamic testing.
      • Braking distance (100 - 5 km/h).
      • SAE J1263 coast downs.

3. Part 1 – Rolling Resistance Coefficients Results

The large graph illustrates the SMERFs for all twenty-five tires tested. The tires were grouped using a colour-coded scheme based on their standard deviation or variance from the average rolling resistance of all 25 tires tested. By grouping tires in this fashion, it is possible to see how a particular tire is rated with respect to other tires. The graph shows that the difference between the tires having the highest and the lowest SMERF is 46%. The link between the effects of rolling resistance on actual fuel consumption will be explored further in future testing.
By presenting information like the SMERF on a label, consumers would be able to compare tires based on their ability to save fuel. Two figures on the right present the labels proposed by the European Union (left) and National Highway Traffic Safety Administration (NHTSA) respectively.

Findings

  • Within the sample of 25 tires tested, there was a 46% variance in rolling coefficients.
  • Rolling resistance also appeared to be independent of tire classification (all season vs. winter).

3. Part 1 – Braking Distance Results

Does rolling resistance affect braking distance?

The braking distance is graphed in relation to the rolling resistance coefficients of each tire tested. The graph shows that the vehicle equipped with the lowest rolling resistance tire stopped within a distance of 45.3 metres, or 24.7 metres shorter than required under CMVSS TSD 135 S7.5. This is an acceptable result. Tires 21 and 22 required approximately 8% greater distance (2-3 metres) to come to a full stop than the other four tires in their group. Although the vehicles met CMVSS standards with all the tire models tested, preliminary results suggested that decreasing rolling resistance could result in a slight increase in braking distance. However, more study is required with larger sample and repeated tests.

Findings

  • Preliminary findings suggest there is no correlation between rolling resistance and braking distance.

3. Part 1 – Coast Down Results

Does rolling resistance affect coast down times?

The graph plots speed versus time of 10 tires, when a vehicle was coasted down from 105 km/h to 15 km/h. The graph shows that a vehicle equipped with a lower rolling resistance tire takes longer to coast down. there is a 39% difference within eTV’s sample between the tires having the highest and the lowest rolling resistance coefficients. This 39% difference in rolling resistance resulted in a 15% longer coast down time from 105 km/h to 15 km/h. In practical terms, therefore, this shows that a vehicle equipped with lower rolling resistance tires requires less energy to overcome rolling resistance, and thus can achieve better fuel efficiency.

Findings

  • On-road tests results indicate a correlation between tire rolling resistance values and coast down times – supporting the fuel savings potential of LRR tires.

3. Part 1 – Treadwear vs. Rolling Resistance

Do tires with a lower rolling resistance coefficient wear faster?

The graph plots tread wear versus rolling resistance. It shows that, for the 25 tires tested, there does not appear to be a relationship between tread wear and rolling resistance. In other words, the low rolling resistance tires in the eTV sample do not seem to wear out faster.

Findings

  • Preliminary tests suggest that there is no obvious relationship between tread wear and rolling resistance.

3. Part 1 – Wet Traction vs. Rolling Resistance

Does a lower rolling resistance value compromise traction?

The figure plots traction versus rolling resistance. It shows that, for the 25 tires tested, rolling resistance did not affect wet traction. All tire models tested displayed good to excellent wet traction capabilities, with an asphalt deceleration rate of higher than 0.47 g (4.61 m/s2).

Findings

  • Tests did not demonstrate any apparent relationship between UTQG traction and rolling resistance.

3. Part 1 – Cost vs. Rolling Resistance

Do tires with a lower rolling resistance coefficient cost more?

The figure plots price in relation to rolling resistance for all 25 tires tested. It shows that, for the 25 tires tested, there is no direct relationship between rolling resistance and tire price. The tires with the lowest rolling resistance had an average price of $143 per tire. While tire costs can range from $35 to $250, the average cost of conventional replacement tires is about $130 per tire. Based on eTV’s sample, buying a set of four tires with a low rolling resistance coefficient could cost up to $52 more than a set of conventional tire. However, if one considers that the average Canadian spends about $2,000 a year on fuel, each 1% reduction in fuel use equals approximately $20 in savings per year. A 3.0% to 4.6% improvement in fuel consumption could therefore mean a savings of $60 to $92 per year.

Findings

  • Tests did not demonstrate any correlation between price and rolling resistance.

3. Part 1: Summary

  • Based on a preliminary investigation of 25 tires, results suggest that LRR tire technologies can help reduce fuel consumption of light-duty vehicles without negatively affecting traction, braking performance or tire life (tread wear).
  • However, what about heavy-duty (e.g. Class VIII Long-Haul) vehicles?

4. PART 2 – Investigations into Class 8 Heavy Duty Vehicles (HDVs) Low Rolling Resistance (LRR) and Single Wide Based (SWB) Tires

Rationale

  • North American GHG programs for heavy-duty vehicles will accelerate the market uptake of LRR and SWB tires;
  • Canadian industry has cited concerns about traction capabilities of LRR tires under certain cold weather (winter) conditions;
  • and, Transport Canada is studying correlations between rolling resistance and durability, and winter traction.

Objectives

  • Study correlations between rolling resistance, durability, and traction;
  • Provide Transport Canada with data to better understand tire performance;
  • and, Share results with other Federal departments (Environment Canada, Natural Resources Canada) who share aspects of tire regulation and reporting.

4. PART 2: Testing Methodology

Testing comprised of 2 main approaches:

  • 1. Laboratory Testing Smithers Rapra (Ravenna, OH)


    Rolling resistance and durability testing machine

  • 2. Dynamic (Track) Testing Smithers Rapra Winter Tire Testing Facility (Brimley, Michigan) GMs Cold Weather Testing Facility (Kapuskasing, ON)


    Class VIII heavy duty vehicle (18 wheel)

4. Part 2: Laboratory Testing

A minimum of 10 distinct LRR EPA SmartWay-verified tires, and approximately 8 non-LRR tires (295/75R22.5 or equivalent), and up to 10 distinct SWB tires (445/50/R22.5).

Testing objectives are to evaluate:

  • Rolling Resistance (ISO 28580)
  • Endurance (CMVSS 119)
  • Snow traction performance (modified ASTM F1805)

Data captured or calculated

  • Rolling resistance coefficients
  • Change in tire pressure, time to failure, type of failure
  • Traction coefficients, acceleration (m/s2 or G)

5. Moving Forward

  • Laboratory testing will evaluate relationships between rolling resistance, durability, and winter traction of tires under controlled conditions.
    • Results are expected by March 31, 2012.
  • Winter performance track testing will evaluate relationships between rolling resistance and straight line braking, acceleration and low speed turning on snow covered pavement.
    • Results are expected by April 30, 2012.
  • Summer performance testing will evaluate relationships between rolling resistance and straight line braking, acceleration, and low speed turning on wet pavement.
    • Results are expected by June 30, 2012.

The need for additional testing will be assessed in mid-2012 and if work is needed, it will be completed in the winter of 2012/2013.

To access the Portable Document Format (PDF) version you must have a PDF reader installed. If you do not already have such a reader, there are numerous PDF readers available for free download or for purchase on the Internet:

Please note: The following hyperlinks are to sites of organizations or other entities that are not subject to the Official Languages Act. The material found there is therefore in the language(s) used by the sites in question.

Date modified: