DECODING TYRE LABELLING AND MARKINGS
To assist us in our choice of tyres, for once, EU legislation actually comes to the rescue! From 1st November 2012 tyre-labelling laws came into force, which require all tyres to bear a label similar to that found on domestic white goods, detailing wet grip, fuel efficiency and noise level. Additionally, moulded into the sidewall can be found the American ‘UTQG’ ( Uniform Tire Quality Grade) specification too.
FUEL EFFICIENCY
Rated A– G, best to worst. However, for our purposes this is a difficult property to interpret, as to a large extent rolling resistance equates to grip, hence we might actually regard G as a good thing. R888R – F T1-Sport – E
WET GRIP
Rated A– G, best to worst. A is definitely most desirable. As a comparison, an F-rated tyre can take an additional 18 metres to stop from 50mph than an A-rated tyre. Meaning when the A-rated tyre has stopped the F-rated tyre is still doing around 30mph, which could the difference between no crash and a major incident! R888R – E T1-Sport – B
NOISE LEVELS
Rated with 1, 2 or 3 black bars and the tyre dB rating. The lower these numbers, the better. This quality tends to go hand in hand with comfort and is arguably of little interest to performance car enthusiasts. R888R – 71dB T1-Sport – 71dB
TREADWEAR
The higher the number, the better the longevity (100/280). 100 denotes a standard test cycle, so 280 would theoretically last 2.8 times longer. R888R – 100 T1-Sport – 280
TRACTION
An indicator of wet traction performance, AA –A – BC in descending performance order. R888R – AA T1-Sport – AA
TEMPERATURE
The ability to dissipate destructive heat build-up, A– B – C in descending capacity. R888R – A T1-Sport – A Also on the sidewall, there is an age indicator, a four-figure code showing week and year of manufacture. In the illustration this shows 3407: the 34th week of 2007. Why does this matter? Well, tyres can be considered to have a ‘use by’ date. Most manufacturers recommend an age limit of 6 years, but in the case of a track focused tyres such as the R888R this is reduced to 2 years.
Time has a profound effect on tyre performance and safety. Compounds and structure age harden, exacerbated by natural exposure to light, heat and moisture, resulting in harshness and reduced grip. The tread can be unworn, but close inspection may reveal surface cracking in the base of the tread groves and sidewalls, which can lead to catastrophic structural failure.