# L_2011317EN.01001701.xml

| 30.11.2011 | EN | Official Journal of the European Union | L 317/17 |
| --- | --- | --- | --- |

30.11.2011

EN

Official Journal of the European Union

L 317/17

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COMMISSION REGULATION (EU) No 1235/2011

of 29 November 2011

amending Regulation (EC) No 1222/2009 of the European Parliament and of the Council with regard to the wet grip grading of tyres, the measurement of rolling resistance and the verification procedure

(Text with EEA relevance)

THE EUROPEAN COMMISSION,

Having regard to the Treaty on the Functioning of the European Union,

Having regard to Regulation (EC) No 1222/2009 of the European Parliament and of the Council of 25 November 2009 on the labelling of tyres with respect to fuel efficiency and other essential parameters (1), and in particular Article 11(a) and (c) thereof,

Whereas:

| (1) | Regulation (EC) No 1222/2009 of the European Parliament and of the Council aims at establishing a framework for the provision of harmonised information on tyre parameters through labelling, allowing end-users to make an informed choice when purchasing tyres. |
| --- | --- |

(1)

Regulation (EC) No 1222/2009 of the European Parliament and of the Council aims at establishing a framework for the provision of harmonised information on tyre parameters through labelling, allowing end-users to make an informed choice when purchasing tyres.

| (2) | The rolling resistance of tyres determines their fuel efficiency grading. Measurement of rolling resistance must be reproducible; tests on the same tyres in different laboratories must produce the same results in order to ensure a fair comparison between tyres from different suppliers. In addition, a good reproducibility of testing results prevents market surveillance authorities from obtaining different results from those of the suppliers when testing the same tyres. |
| --- | --- |

(2)

The rolling resistance of tyres determines their fuel efficiency grading. Measurement of rolling resistance must be reproducible; tests on the same tyres in different laboratories must produce the same results in order to ensure a fair comparison between tyres from different suppliers. In addition, a good reproducibility of testing results prevents market surveillance authorities from obtaining different results from those of the suppliers when testing the same tyres.

| (3) | A procedure for the alignment of test laboratories with regard to the measurement of rolling resistance would improve the reproducibility of the testing results. |
| --- | --- |

(3)

A procedure for the alignment of test laboratories with regard to the measurement of rolling resistance would improve the reproducibility of the testing results.

| (4) | Since a suitable harmonised testing method of grip on wet roads has been developed at ISO level, a wet grip grading of C2 and C3 tyres should now be introduced, in accordance with Article 11 (a) of Regulation (EC) No 1222/2009. |
| --- | --- |

(4)

Since a suitable harmonised testing method of grip on wet roads has been developed at ISO level, a wet grip grading of C2 and C3 tyres should now be introduced, in accordance with Article 11 (a) of Regulation (EC) No 1222/2009.

| (5) | The clarity of the conformity verification procedure set out in Annex IV of Regulation (EC) No 1222/2009 should be improved by introducing thresholds according to which the declared values used for the labelling requirements are considered to be in compliance with that Regulation. |
| --- | --- |

(5)

The clarity of the conformity verification procedure set out in Annex IV of Regulation (EC) No 1222/2009 should be improved by introducing thresholds according to which the declared values used for the labelling requirements are considered to be in compliance with that Regulation.

| (6) | Regulation (EC) No 1222/2009 should therefore be amended accordingly. |
| --- | --- |

(6)

Regulation (EC) No 1222/2009 should therefore be amended accordingly.

| (7) | The measures provided for in this Regulation are in accordance with the opinion of the Committee established by Article 13 of Regulation (EC) No 1222/2009, |
| --- | --- |

(7)

The measures provided for in this Regulation are in accordance with the opinion of the Committee established by Article 13 of Regulation (EC) No 1222/2009,

HAS ADOPTED THIS REGULATION:

Article 1

Amendment to Regulation (EC) No 1222/2009

Regulation (EC) No 1222/2009 is amended as follows:

| (1) | Annex I, part A: Fuel efficiency classes, the first sentence is replaced by the following:

  ‘The fuel efficiency class must be determined on the basis of the rolling resistance coefficient (RRC) according to the “A” to “G” scale specified below and measured in accordance with Annex 6 of UNECE Regulation No 117 and its subsequent amendments and aligned according to the procedure laid down in Annex IVa.’; |
| --- | --- |

(1)

Annex I, part A: Fuel efficiency classes, the first sentence is replaced by the following:

‘The fuel efficiency class must be determined on the basis of the rolling resistance coefficient (RRC) according to the “A” to “G” scale specified below and measured in accordance with Annex 6 of UNECE Regulation No 117 and its subsequent amendments and aligned according to the procedure laid down in Annex IVa.’;

RRC

| (2) | in Annex I, part B: Wet grip classes, the text and table are replaced by the following:






  ‘1. | The wet grip class of C1 tyres must be determined on the basis of the wet grip index (G) according to the “A” to “G” scale specified in the table below, calculated in accordance with point 3 and measured in accordance with Annex V. |
| --- | --- | --- |

(2)

in Annex I, part B: Wet grip classes, the text and table are replaced by the following:

‘1.

The wet grip class of C1 tyres must be determined on the basis of the wet grip index (G

| 2. | The wet grip class of C2 and C3 tyres must be determined on the basis of the wet grip index (G) according to the “A” to “G” scale specified in the table below, calculated in accordance with point (3) and measured in accordance with ISO 15222:2011 whereby the following Standard Reference Test Tyres (SRTT) must be used:






  (i) | for C2 tyres, the SRTT 225/75 R 16 C, ASTM F 2872-11; |
| --- | --- | --- |

2.

The wet grip class of C2 and C3 tyres must be determined on the basis of the wet grip index (G

(i)

for C2 tyres, the SRTT 225/75 R 16 C, ASTM F 2872-11;

| (ii) | for C3 tyres having Nominal Section Width lower than 285 mm, the SRTT 245/70R19.5, ASTM F 2871-11; |
| --- | --- |

(ii)

for C3 tyres having Nominal Section Width lower than 285 mm, the SRTT 245/70R19.5, ASTM F 2871-11;

| (iii) | for C3 tyres having Nominal Section Width greater than or equal to 285 mm, the SRTT 315/70R22.5, ASTM F 2870-11. |
| --- | --- |

(iii)

for C3 tyres having Nominal Section Width greater than or equal to 285 mm, the SRTT 315/70R22.5, ASTM F 2870-11.

| 3. | Calculation of wet grip index (G)


  G = G(T) – 0,03
  where: G(T) = wet grip index of the candidate tyre as measured in one test cycle










  C1 tyres | C2 tyres | C3 tyres |
| --- | --- | --- | --- |
| G | Wet grip class | G | Wet grip class | G | Wet grip class |
| 1,55 ≤ G | A | 1,40 ≤ G | A | 1,25 ≤ G | A |
| 1,40 ≤ G ≤ 1,54 | B | 1,25 ≤ G ≤ 1,39 | B | 1,10 ≤ G ≤ 1,24 | B |
| 1,25 ≤ G ≤ 1,39 | C | 1,10 ≤ G ≤ 1,24 | C | 0,95 ≤ G ≤ 1,09 | C |
| Empty | D | Empty | D | 0,80 ≤ G ≤ 0,94 | D |
| 1,10 ≤ G ≤ 1,24 | E | 0,95 ≤ G ≤ 1,09 | E | 0,65 ≤ G ≤ 0,79 | E |
| G ≤ 1,09 | F | G ≤ 0,94 | F | G ≤ 0,64 | F |
| Empty | G | Empty | G | Empty | G’ |

3.

Calculation of wet grip index (G)

G = G(T) – 0,03

G

G(T)

where: G(T) = wet grip index of the candidate tyre as measured in one test cycle

G(T)

C1 tyres

C2 tyres

C3 tyres

G

G

Wet grip class

G

G

Wet grip class

G

G

Wet grip class

1,55 ≤ G

G

A

1,40 ≤ G

G

A

1,25 ≤ G

G

A

1,40 ≤ G ≤ 1,54

G

B

1,25 ≤ G ≤ 1,39

G

B

1,10 ≤ G ≤ 1,24

G

B

1,25 ≤ G ≤ 1,39

G

C

1,10 ≤ G ≤ 1,24

G

C

0,95 ≤ G ≤ 1,09

G

C

Empty

D

Empty

D

0,80 ≤ G ≤ 0,94

G

D

1,10 ≤ G ≤ 1,24

G

E

0,95 ≤ G ≤ 1,09

G

E

0,65 ≤ G ≤ 0,79

G

E

G ≤ 1,09

G

F

G ≤ 0,94

G

F

G ≤ 0,64

G

F

Empty

G

Empty

G

Empty

G’

| (3) | Annex IV: Verification procedure, is replaced by the following:



  ‘ANNEX IV

  Verification procedure

  The conformity of the declared fuel efficiency and wet grip classes, as well as the declared external rolling noise class and declared value, must be assessed for each tyre type or each grouping of tyres as determined by the supplier, according to one of the following procedures:






  (a) | (i) | a single tyre or tyre set is tested first. If the measured values meet the declared classes or external rolling noise declared value to within the tolerance defined in Table 1, the test is successfully passed; and |
| --- | --- | --- | --- |

(3)

Annex IV: Verification procedure, is replaced by the following:

‘ANNEX IV

Verification procedure

The conformity of the declared fuel efficiency and wet grip classes, as well as the declared external rolling noise class and declared value, must be assessed for each tyre type or each grouping of tyres as determined by the supplier, according to one of the following procedures:

(a)

(i)

a single tyre or tyre set is tested first. If the measured values meet the declared classes or external rolling noise declared value to within the tolerance defined in Table 1, the test is successfully passed; and

| (ii) | if the measured values do not meet the declared classes or external rolling noise declared value within the range defined in Table 1, three more tyres or tyre sets are tested. The average measurement value stemming from the three tyres or tyre sets tested is used to assess conformity with the declared information within the range defined in Table 1; or |
| --- | --- |

(ii)

if the measured values do not meet the declared classes or external rolling noise declared value within the range defined in Table 1, three more tyres or tyre sets are tested. The average measurement value stemming from the three tyres or tyre sets tested is used to assess conformity with the declared information within the range defined in Table 1; or

| (b) | where the labelled classes or values are derived from type approval test results obtained in accordance with Directive 2001/43/EC, Regulation (EC) No 661/2009, or UNECE Regulation No 117 and its subsequent amendments, Member States may make use of measurement data obtained from conformity of production tests on tyres. |
| --- | --- |

(b)

where the labelled classes or values are derived from type approval test results obtained in accordance with Directive 2001/43/EC, Regulation (EC) No 661/2009, or UNECE Regulation No 117 and its subsequent amendments, Member States may make use of measurement data obtained from conformity of production tests on tyres.

Assessment of the measurement data obtained from the conformity of production tests must take into account the allowances defined in Table 1.

Table 1

| Measured parameter | Verification tolerances |
| --- | --- |
| Rolling resistance coefficient (fuel efficiency) | The aligned measured value shall not be greater than the upper limit (the highest RRC) of the declared class by more than 0,3 kg/1 000 kg. |
| External rolling noise | The measured value shall not be greater than the declared value of N by more than 1 dB(A). |
| Wet grip | The measured value shall not be lower than the lower limit (the lowest value of G) of the declared class.’ |

Measured parameter

Verification tolerances

Rolling resistance coefficient (fuel efficiency)

The aligned measured value shall not be greater than the upper limit (the highest RRC) of the declared class by more than 0,3 kg/1 000 kg.

External rolling noise

The measured value shall not be greater than the declared value of N by more than 1 dB(A).

Wet grip

The measured value shall not be lower than the lower limit (the lowest value of G) of the declared class.’

| (4) | the text set out in the Annex to this Regulation is added as Annex IVa. |
| --- | --- |

(4)

the text set out in the Annex to this Regulation is added as Annex IVa.

Article 2

Entry into force

This Regulation shall enter into force on the 20th day following its publication in the Official Journal of the European Union.

Official Journal of the European Union

This Regulation shall apply from 30 May 2012.

This Regulation shall be binding in its entirety and directly applicable in all Member States.

Done at Brussels, 29 November 2011.

For the Commission

The President

José Manuel BARROSO

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(1)  
  OJ L 342, 22.12.2009, p. 46.

1

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ANNEX

‘ANNEX IVa

Laboratory alignment procedure for the measurement of rolling resistance

1.   DEFINITIONS

For the purpose of the laboratory alignment procedure, the following definitions apply:

| (1) | “Reference laboratory” means a laboratory that is part of the network of laboratories the references of which have been published for the purpose of the alignment procedure in the Official Journal of the European Union, and is able to achieve the accuracy of test results determined in section 3; |
| --- | --- |

(1)

“Reference laboratory” means a laboratory that is part of the network of laboratories the references of which have been published for the purpose of the alignment procedure in the Official Journal of the European Union, and is able to achieve the accuracy of test results determined in section 3;

| (2) | “Candidate laboratory” means a laboratory participating in the alignment procedure that is not a reference laboratory; |
| --- | --- |

(2)

“Candidate laboratory” means a laboratory participating in the alignment procedure that is not a reference laboratory;

| (3) | “Alignment tyre” means a tyre that is tested for the purpose of performing the alignment procedure; |
| --- | --- |

(3)

“Alignment tyre” means a tyre that is tested for the purpose of performing the alignment procedure;

| (4) | “Alignment tyres set” means a set of five or more alignment tyres; |
| --- | --- |

(4)

“Alignment tyres set” means a set of five or more alignment tyres;

| (5) | “Assigned value” means a theoretical value of one alignment tyre as measured by a theoretical laboratory which is representative of the network of reference laboratories that is used for the alignment procedure. |
| --- | --- |

(5)

“Assigned value” means a theoretical value of one alignment tyre as measured by a theoretical laboratory which is representative of the network of reference laboratories that is used for the alignment procedure.

2.   GENERAL PROVISIONS

2.1.   Principle

The measured Rolling Resistance Coefficient (RRCm
  ) in a reference laboratory (l) shall be aligned to the assigned values of the network of reference laboratories.

The RRCm
  in a candidate laboratory (c) shall be aligned through one reference laboratory of the network of its choice.

2.2.   Tyre selection requirements

A set of five or more alignment tyres shall be selected for the alignment procedure in compliance with the criteria below. One set shall be selected for C1 and C2 tyres together, and one set for C3 tyres.

| (a) | The set of alignment tyres shall be selected so as to cover the range of different RRCs of C1 and C2 tyres together, or of C3 tyres. In any event, the difference between the highest RRCm
  of the tyre set, and the lowest RRCm
  of the tyre set shall be at least equal to:






  (i) | 3 kg/t for C1 and C2 tyres; and |
| --- | --- | --- |

(a)

The set of alignment tyres shall be selected so as to cover the range of different RRCs of C1 and C2 tyres together, or of C3 tyres. In any event, the difference between the highest RRCm
  of the tyre set, and the lowest RRCm
  of the tyre set shall be at least equal to:

(i)

3 kg/t for C1 and C2 tyres; and

| (ii) | 2 kg/t for C3 tyres. |
| --- | --- |

(ii)

2 kg/t for C3 tyres.

| (b) | The RRCm
  in the candidate or reference laboratories (c or l) based on declared RRC values of each alignment tyre of the set shall be spaced out as follows and distributed uniformly:






  (i) | 1,0 +/– 0,5 kg/t for C1 and C2 tyres; and |
| --- | --- | --- |

(b)

The RRCm
  in the candidate or reference laboratories (c or l) based on declared RRC values of each alignment tyre of the set shall be spaced out as follows and distributed uniformly:

(i)

1,0 +/– 0,5 kg/t for C1 and C2 tyres; and

| (ii) | 1,0 +/– 0,5 kg/t for C3 tyres. |
| --- | --- |

(ii)

1,0 +/– 0,5 kg/t for C3 tyres.

| (c) | The selected tyre section width of each alignment tyre shall be:






  (i) | ≤ 245 mm for machines measuring C1 and C2 tyres; and |
| --- | --- | --- |

(c)

The selected tyre section width of each alignment tyre shall be:

(i)

≤ 245 mm for machines measuring C1 and C2 tyres; and

| (ii) | ≤ 385 mm for machines measuring C3 tyres. |
| --- | --- |

(ii)

≤ 385 mm for machines measuring C3 tyres.

| (d) | The selected tyre outer diameter of each alignment tyre shall be:






  (i) | between 510 to 800 mm for machines measuring C1 and C2 tyres; and |
| --- | --- | --- |

(d)

The selected tyre outer diameter of each alignment tyre shall be:

(i)

between 510 to 800 mm for machines measuring C1 and C2 tyres; and

| (ii) | between 771 to 1 143 mm for machines measuring C3 tyres. |
| --- | --- |

(ii)

between 771 to 1 143 mm for machines measuring C3 tyres.

| (e) | Load index values shall adequately cover the range of the tyres to be tested, ensuring that the rolling resistance force (RRF) values also cover the range of the tyres to be tested.
  Each alignment tyre shall be checked prior to use and replaced when:






  (a) | it shows a condition which makes it unusable for further tests; and/or |
| --- | --- | --- |

(e)

Load index values shall adequately cover the range of the tyres to be tested, ensuring that the rolling resistance force (RRF) values also cover the range of the tyres to be tested.

Each alignment tyre shall be checked prior to use and replaced when:

(a)

it shows a condition which makes it unusable for further tests; and/or

| (b) | there are deviations of RRCm
  greater than 1,5 per cent relative to earlier measurements after correction for any machine drift. |
| --- | --- |

(b)

there are deviations of RRCm
  greater than 1,5 per cent relative to earlier measurements after correction for any machine drift.

2.3.   Measurement method

The reference laboratory shall measure each alignment tyre four times and retain the three last results for further analysis, in accordance with paragraph 4 of Annex 6 of UNECE Regulation No 117 and its subsequent amendments and applying the conditions set out in paragraph 3 of Annex 6 of UNECE Regulation No 117 and its subsequent amendments.

The candidate laboratory shall measure each alignment tyre (n + 1) times with n being specified in section 5 and retain the n last results for further analysis, in accordance with paragraph 4 of Annex 6 of UNECE Regulation No 117 and its subsequent amendments and applying the conditions set out in paragraph 3 of Annex 6 of UNECE Regulation No 117 and its subsequent amendments.

Each time an alignment tyre is measured, the tyre/wheel assembly shall be removed from the machine and the entire test procedure specified in paragraph 4 of Annex 6 of UNECE Regulation No 117 and its subsequent amendments shall be followed again from the start.

The candidate or reference laboratory shall calculate:

| (a) | the measured value of each alignment tyre for each measurement as specified in Annex 6, paragraphs 6.2 and 6.3, of UNECE Regulation No 117 and its subsequent amendments (i.e. corrected for a temperature of 25 °C and a drum diameter of 2 m); |
| --- | --- |

(a)

the measured value of each alignment tyre for each measurement as specified in Annex 6, paragraphs 6.2 and 6.3, of UNECE Regulation No 117 and its subsequent amendments (i.e. corrected for a temperature of 25 °C and a drum diameter of 2 m);

| (b) | the mean value of the three (in the case of reference laboratories) or n (in the case of candidate laboratories) last measured values of each alignment tyre; and |
| --- | --- |

(b)

the mean value of the three (in the case of reference laboratories) or n (in the case of candidate laboratories) last measured values of each alignment tyre; and

| (c) | the standard deviation (σm) as follows:










  where:






  i | is the counter from 1 to p for the number of alignment tyres |
| --- | --- | --- |
| j | is the counter from 2 to n for the number of repetitions of each measurement for a given alignment tyre |
| n | is the number of repetitions of tyre measurements (n ≥4) |
| p | is the number of alignment tyres (p ≥ 5) |

(c)

the standard deviation (σm) as follows:

Formula

Formula

where:

i

is the counter from 1 to p for the number of alignment tyres

j

is the counter from 2 to n for the number of repetitions of each measurement for a given alignment tyre

n

is the number of repetitions of tyre measurements (n ≥4)

p

is the number of alignment tyres (p ≥ 5)

2.4.   Data formats to be used for the computations and results

| — | The measured RRC values corrected from drum diameter and temperature shall be rounded to 2 decimal places. |
| --- | --- |

—

The measured RRC values corrected from drum diameter and temperature shall be rounded to 2 decimal places.

| — | Then the computations shall be made with all digits: there shall be no further rounding except on the final alignment equations. |
| --- | --- |

—

Then the computations shall be made with all digits: there shall be no further rounding except on the final alignment equations.

| — | All standard deviation values shall be displayed to 3 decimal places. |
| --- | --- |

—

All standard deviation values shall be displayed to 3 decimal places.

| — | All RRC values will be displayed to 2 decimal places. |
| --- | --- |

—

All RRC values will be displayed to 2 decimal places.

| — | All alignment coefficients (A1l, B1l, A2c and B2c) shall be rounded and displayed to 4 decimal places. |
| --- | --- |

—

All alignment coefficients (A1l, B1l, A2c and B2c) shall be rounded and displayed to 4 decimal places.

3.   REQUIREMENTS APPLICABLE TO THE REFERENCE LABORATORIES AND DETERMINATION OF THE ASSIGNED VALUES

The assigned values of each alignment tyre shall be determined by a network of reference laboratories. After two years the network shall assess the stability and validity of the assigned values.

Each reference laboratory participating in the network shall comply with the specifications of Annex 6 of UNECE Regulation No 117 and its subsequent amendments and have a standard deviation (σm) as follows:

| (i) | not greater than 0,05 kg/t for class C1 and C2 tyres; and |
| --- | --- |

(i)

not greater than 0,05 kg/t for class C1 and C2 tyres; and

| (ii) | not greater than 0,05 kg/t for class C3 tyres. |
| --- | --- |

(ii)

not greater than 0,05 kg/t for class C3 tyres.

The sets of alignment tyres, conforming to the specification of section 2.2 shall be measured in accordance with section 2.3 by each reference laboratory of the network.

The assigned value of each alignment tyre is the average of the measured values given by the reference laboratories of the network for this alignment tyre.

4.   PROCEDURE FOR THE ALIGNMENT OF A REFERENCE LABORATORY TO THE ASSIGNED VALUES

Each reference laboratory (l) shall align itself to the assigned values of the alignment tyre set using a linear regression technique, A1
  l
  and B1
  l
  , calculated as follows:

RRC = A1
  l
  - RRC

  m,l
  - B1
  l

where:

| RRC | is the assigned value of the rolling resistance coefficient; |
| --- | --- |
| RRCm, | is the measured value of the rolling resistance coefficient by the reference laboratory ‘l’ (including temperature and drum diameter corrections) |

RRC

is the assigned value of the rolling resistance coefficient;

RRCm,

is the measured value of the rolling resistance coefficient by the reference laboratory ‘l’ (including temperature and drum diameter corrections)

5.   REQUIREMENTS APPLICABLE TO CANDIDATE LABORATORIES

Candidate laboratories shall repeat the alignment procedure at least once every two years and always after any significant machine change or any drift in machine control tyre monitoring data.

A common set of five different tyres, conforming to the specification of section 2.2 shall be measured in accordance with section 2.3 by the candidate laboratory and by one reference laboratory. More than five alignment tyres may be tested at the request of the candidate laboratory.

The alignment tyre set shall be provided by the candidate laboratory to the selected reference laboratory.

The candidate laboratory (c) shall comply with the specifications of Annex 6 of UNECE Regulation No 117 and its subsequent amendments and preferably have standard deviations (σm
  ) as follows:

| (i) | not greater than 0,075 kg/t for C1 and C2 tyres; and |
| --- | --- |

(i)

not greater than 0,075 kg/t for C1 and C2 tyres; and

| (ii) | not greater than 0,06 kg/t for C3 tyres. |
| --- | --- |

(ii)

not greater than 0,06 kg/t for C3 tyres.

If the standard deviations (σm) of the candidate laboratory are higher than the above values with three measurements, then the number of measurement repetitions shall be increased as follows:

n = (σm
  /γ)2, rounded up to the nearest higher integer value

where:

| γ | = | 0,043 kg/t for Class C1 and C2 tyres |
| --- | --- | --- |
| γ | = | 0,035 kg/t for Class C3 tyres |

γ

=

0,043 kg/t for Class C1 and C2 tyres

γ

=

0,035 kg/t for Class C3 tyres

6.   PROCEDURE FOR THE ALIGNMENT OF A CANDIDATE LABORATORY

One reference laboratory (l) of the network shall calculate the linear regression function of the candidate laboratory (c), A2c and B2c, as follows:

RRC

  m,l
  = A2c × RRCm,c
  - B2c

where:

| RRCm,l | is the measured value of the rolling resistance coefficient by the reference laboratory (l) (including temperature and drum diameter corrections) |
| --- | --- |
| RRCm,c | is the measured value of the rolling resistance coefficient by the candidate laboratory (c) (including temperature and drum diameter corrections) |

RRCm,l

is the measured value of the rolling resistance coefficient by the reference laboratory (l) (including temperature and drum diameter corrections)

RRCm,c

is the measured value of the rolling resistance coefficient by the candidate laboratory (c) (including temperature and drum diameter corrections)

The aligned RRC of tyres tested by the candidate laboratory is calculated as follows:

RRC = (A1
  l
  × A2c) × RRCm,c
  - (A1
  l
  × B2c + B1
  l
  )’

---