Tyre labelling info...wet braking

[otherclive]

Does anyone know at what ambient temperature the new tyre tests for wet braking are carried out at. It struck me that as the we are being advised to fit cold weather tyres because 'summer' tyres drop their performance below 7 deg C what temperature are these tests carried out at. Is it a lower temperature for cold weather, or winter tyres tyres than for summer tyres? I know that the tests are lab based but even so temperature influences tyre performance so what does the comparison scale mean other than tyre 1 did better in the lab test than tyre 2. But if tyre 1 is a summer tyre and tyre 2 a cold weather, winter tyre and the test was at normal lab temperature say 18-20 deg then tyre 2 could be as good if not better than tyre 1 at 7 deg. Or is this labelling just another smoke and mirrors activity. Although as regards tyre noise I have found it to be quite revealing.When we changed tyres that were (worn) originally labelled 74db, for new ones labelled 69db. The difference was most noticeable in much quieter running even with the new ones at maximum tread depth, but the damn thing wouldnt pull up (joke).

 

[Lutz]

As far as I have been able to find out, labelling is carried out according to EC 1222/2009 which references the test criteria specified under ECE 117. These call for measurements for the wet braking test to be carried out at an ambient road surface temperature of between 5°C and 35°C. For the purpose of fulfilling the requirements of the regulations, there doesn't appear to be any differentiation between between winter and summer tyres.

 

[otherclive]

Thanks Lutz, it looks delightfully vague probably okay as long as you compare tyres from the same manufacturer; but even that isnt certain as they may test the winter/cold weather tyres at the low temperature and their summer at some higher temperature but there's no guarantee that is the case. Ive concluded that the german Autobild tests are a far better gauge of tyre perfomance than the EC labels. But even with Autobild it would be nice to see an All Seasons such as the new Falken, Nockian or Goodyear Vectors tested in Winter and in Summer temperatures against cold weather and summer tyres in their respective temperature zones. But saying that the Autobild,ACE and ADAC do provide very good test reports and the Autobild All Season test 2013 showed some All Seasons better in Winter conditions than some winter tyres. Cavaet emptor I guess.