Tire Engineer meeting

[Q45tech]

unable to link, search Google for::ASTM E-1136 Standard Reference Test Tire

{{{Unconfirmed Minutes of seventh meeting of UN ECE, GRRF ad-hoc Group on Global Harmonisation of Tyre Regulations and Tyre Grip – held in Brussels 8/9/10 November 2001}}}

"There was general concern that the entire burden for the performance of tyres at significantly low pressures was being placed upon the tyre industry without any requirement for the vehicle manufacturers to specify tyres and inflation pressures that were suitable for the application. There were examples where the load capability and inflation pressure chosen were such that at 20% or 25% under-inflation or 140kPa the tyre would be operating outside the industry’s recommended envelope. It would be an imbalanced burden to expect the tyre industry to take responsibility for this situation and the vehicle manufacturer ought to be required to specify a higher load capability tyre. Industry was also concerned as to precisely what inflation pressure recommendation was to be used for the 20% or 25% under-inflation indication requirement, the placard pressure for maximum load or that for normal load?

Concern was also expressed as to the principle of only warning the driver at the point of minimum pressure and whether this would result in a situation worse than that at present, that is, users would stop checking pressures on a regular basis but would wait until there was a low pressure warning. Industry had suggested an initial indication of pressure below the recommended pressure followed by a warning at the minimum level.

"NHTSA commented that it was trying to assess tyre performance after the completion of around 30 000ml (50 000km) as this was around the life of the tyres that had experienced the problems. In other words the ageing was based on distance rather than time."

NHTSA informed the meeting that all of the information and comments on the various issues raised by the TREAD Act may be found on the NHTSA web site under the Docket Management System. The relevant docket numbers are:

Upgrading of Standards – 8011

TPMS – 8572

Tyre Marking (labeling) – 8296 (Now issued as an NPRM under Docket 11157)

The date of the next full meeting has yet to be agreed but it is hoped to take up the kind invitation of Japan and have a further meeting in Tokyo in Spring.

[Q45tech]

http://www-nrd.nhtsa.dot.gov/v...e.pdf

54 page preliminary report on the affects of tire pressure on tire friction wet and dry in a 225/60/16 tire

35 to 24 to 17 psi wet and dry slide and slipDry slide decreased [3%] wet slide increased [3%] from 35 to 24 psi , but significant problem in going down to 17 psi!!!!!!!!!!!!!

http://www-nrd.nhtsa.dot.gov/vrtc/ca/vr ... a/tpms.htm

[Q45tech]

ABS brake test showing the amount of driver induced variation....averaging greater than 3.5 meters [60mph to zero] between subjects after some training.

Pretty scarey! But proves ABS value in wet stopshttp://www-nrd.nhtsa.dot.gov/v...t.pdf

If the above doesn't get you:http://www-nrd.nhtsa.dot.gov/v...2.pdf

Shows how much better a Dodge neon, Chev Impala, is than a Ford Explorer or truck unless you count the fact that tires came off the Chev and they couldn't complete the tests.

Scarey at the failures the government gets trying to do simple tests........The Tarus had a ABS brake failure!