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DEKRA Test CenterOn the safe side

Field survey on tire inflation of

M1 vehicles - December 2017

DEKRA Test Center reference : 17T&E11-149

DEKRA report reference 17T&E11-149 of survey performed from 11th of September to 4th of October 2017 is only valid in its entirety.

An extraction or partial utilization of results for external publication will be under T&E responsibility.


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Aim of the survey

General criteria

Test protocol

Location of the survey

Data processing

Results

Seite 2

Agenda

DEKRA Test Center reference :17T&E11-149


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The aim of this survey is first to collect the actual tire inflations and corresponding tire pressuresrecommended by the vehicles manufacturers, and then to calculate and draw the distributions of tireunderinflations/overinflations, and this for the 3 following groups of vehicles:

- Group “R64 dTPMS vehicles” are vehicles equipped with an UNECE Regulation No. R64 TPMS (TirePressure Monitoring System) based on the direct technology (which uses an actual factory calibratedpressure sensor to measure each tire pressure).

- Group “R64 iTPMS vehicles” are vehicles equipped with an UNECE Regulation No. R64 TPMS basedon the indirect technology (which uses the ABS/ESP tooth wheel sensors to estimate indirectly each tirepressure based on wheel rotation speed and vibration).

- Group “no TPMS vehicles” are vehicles not equipped with a TPMS nor with a tire puncture detectionsystem.

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Aim of the survey



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Seite 4

General criteria


This field survey will be done in 2 different locations : 1 in Portugal and 1 in Italy, and will cover around 1000 vehicles altogether.

It will include only M1 vehicles firstly registered in EU after Nov 1st 2014 in case of Group “R64 dTPMS vehicles” and Group “R64 iTPMS vehicles”.

It will include only M1 vehicles firstly registered in EU after Jan 1st 2009 and before Jan 1st 2014 in case of Group “no TPMS vehicles”.


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Date, time and location of the survey

Vehicle’s brand & model

Vehicle’s VIN number

Vehicle load (partially loaded, fully loaded)

Tire size

Tire flange temperature

Relative tire pressure

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Test protocolData to record Post processed data

Vehicle’s date of 1st registration

TPMS equipment (dTPMS, iTPMS or no TPMS)

Recommended tire pressure placard



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Manometer

Natech

N°IT3471-03

Measurement accuracy : 0,05b

Daily compared with manometer : AQ336

Thermometer

RS – 1319A

Serial N° : 100905687 / 100905660 / 100905682

Measurement accuracy : 0,1°C

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Test protocolEquipment used



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Test protocolProcess*

Ask if the customeris the onlyuser of the vehicle

Ask to the user the yearof the 1st registration

Take the VIN number (afterasking to the user)

Take the dimension of tires, and the visual load

Measure the temperatureand the pressure of tires

*The process applied by DEKRA Test Center for the survey was discussed, adapted and approved by T&E.



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Location of the surveyRoma, Italy

The survey took place in a shopping mall in Roma from the 11th ofSeptember to the 04th of October 2017.

According to the statistics of the shopping mall, customers come fromthe 80km around Rome.

CENTRE5%

EST43%

NO ROMA6%

NORTH17%

SOUTH29%

Location of customers surveyed



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Data processing

With the VIN number, some researches are done :

Check of the date of registration (Internet bank info + car dealership)

Recommended pressure (Internet bank info + car dealership)

Type of TPMS (car dealership)

Vehicles are sorted to keep only the vehicles which we have all the exact information, and sorted in 3 groups :

noTPMS

dTPMS

iTPMS



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Data processing

Pressure measured is corrected with temperature :

Normalized cold actual tire pressure = ((measured tire pressure + 101) x (measured ambient temperature + 273)/(measured tire flange temperature + 273)) – 101

Then pressure delta is calculated between this normalized cold actual pressure and the recommended pressure for each wheel.



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Results

Roma

Seite 11

619 vehicles validated* with :

267 noTPMS

150 iTPMS

202 dTPMS


* : Data processing on all measured vehicles requested by T&E (without taking care of balance ratio between each category)



No TPMS;

267

iTPMS; 150

dTPMS; 202

619 validated vehicles


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Results

Roma

Seite 12

619 vehicles validated *NB: 1 car = 4 wheels




At least 1 wheel

underinflated of

0,3b or more

At least 1 wheel

underinflated of

0,5b or more

Wheels

underinflated of

0,3b or more

Wheels

underinflated of

0,5b or more

No TPMS 41% 15% 23% 8%

iTPMS 33% 11% 18% 4%

dTPMS 28% 6% 14% 3%

TOTAL 35% 11% 19% 5%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

NoTPMS

iTPMS dTPMS TOTAL

Perc

en

tag

e o

f cars

At least 1 wheelunderinflated of0,3b or more

At least 1 wheelunderinflated of0,5b or more

0%

5%

10%

15%

20%

25%

NoTPMS

iTPMS dTPMS TOTALP

erc

en

tag

e o

f w

heels

Wheelsunderinflated of0,3b or more

Wheelsunderinflated of0,5b or more


DEKRA Test Center

Results

Roma

Seite 12

619 vehicles validated




Cars with at least 1

wheel inflated at 1,5b

or less

No TPMS 7%

iTPMS 3%

dTPMS 1%

TOTAL 4%

0%

1%

2%

3%

4%

5%

6%

7%

8%

No TPMS iTPMS dTPMS TOTAL

Perc

en

tag

e o

f cars

Cars with at least 1 wheelinflated at 1,5b or less


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Results

Roma

Seite 13

Pressure delta are gathered as follows : P-0,05b < P < P+0,05b.

Example : P+0,4 gathers pressure delta from P+0,35 to P+0,45.




0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

Perc

en

tag

e o

f w

heels

Pressure delta (bar)

Distribution of tire pressure per wheel

No TPMS

iTPMS

dTPMS

Total

OverinflationUnderinflation

Prec


DEKRA Test Center

Seite 14

Pressure delta are gathered as follows : P-0,05b < P < P+0,05b.

Example : P+0,4 gathers pressure delta from P+0,35 to P+0,45.

Results

Roma




0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

22%

Perc

en

tag

e o

f w

ors

t ti

re p

er

car

Pressure delta (bar)

Distribution of worst tire pressure per car

No TPMS

iTPMS

dTPMS

Total

Underinflation Overinflation

Prec


MISSION

SAFETY

Seite 16

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