GERMAN/ISO PROPOSAL

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Informal document No. GRRF-57-26 (57th GRRF, 31
January-4 February 2005, agenda item 5.2.)
Tyre Adhesion Performance on Wet Surfaces
Regulation Report of the GRRF ad hoc group
meeting
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HISTORY

• BACKGROUND
• EU legislation on tyre noise
• Tyre ad-hoc group formed
• Test method
• Wet adhesion thresholds
• Proposal to GRRF

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WET GRIP THRESHOLDS

• Ad hoc Group proposal
• MS  Tyres  depending on the speed
  category
• ICE TYRES Speed Category lt Q (160km/h not
  including H)
• ? threshold 90
• OTHER MS Speed Category gt Q (including H)
• ? threshold 100
• NORMAL TYRES   All Speed Categories
• ? threshold 110
• Standard Reference Test Tyre (SRTT) is used as
  the bench mark (i.e. threshold 100) for
  comparison with the test tyre.

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PERCENTAGE OF TYRES NOT MEETING THE LIMITS
Wet grip index cumulative distribution curve for
the European tyre market
Representing more than 270 Million tyres produced
per year
cumulative
100
90
80
70
All tyres
110 Threshold for
Av. w/o MS
60
Normal tyres
50
100 Threshold for
40
MS gt 160 km/h
30
90 Threshold for MS lt 160 km/h
20
10
wet grip
index
0
80
90
100
110
120
130
140
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CONCLUSIONS

• Ad-hoc group representation
• Test method (Vehicle and Trailer)
• Wet adhesion thresholds (GRRF decision)
• Proposal from ad-hoc group to include wet
  adhesion requirements in to R.117 (Rolling Sound
  Regulation)
• GRRF and GRB (Joint session)

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THANK YOU FOR YOUR ATTENDANCE