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Tyre speed ratings What do they mean?

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    Carmakers are required to fit tyres that can match a car's top speed

A common misconception is that a tyre with a high-speed rating will be a better handling tyre.

It's not necessarily the case, although most high performance tyres do exhibit better road handling characteristics.

The 'speed rating' of a tyre shown on the tyre sidewall is the speed it can withstand for a period of time without disintegrating. It is measured by running the tyre, under load, against a large drum.

To achieve a speed rating the tyre is run at different speeds for periods of time according to an accepted international standard.

Common speed ratings are:

  • S   180 km/h
  • T   190 km/h
  • U   200 km/h
  • H   210 km/h
  • V   240 km/h
  • W  (ZR) 270 km/h
  • Y   (ZR) 300 km/h
  • ZR   Above 240 km/h

Carmakers are required to fit tyres that can match a car's top speed, but when owners come to fit replacement tyres to their car they have to be minimum of S rated, which is 180 km/h.

The speed rating is moulded into the sidewall of all tyres along with the size and load rating.

Comments on this story

Displaying 3 of 3 comments

  • Peter is correct.

    In SA Refer to Road Traffic (Vehicle Standards) Rules 1999
    Part 5—General safety requirements, Division 1—All vehicles,
    Section 52—Tyres—manufacturer’s rating
    It says :
    Para (3) A tyre fitted to a motor vehicle must, when first manufactured, have been rated by the
    tyre manufacturer as suitable for road use at the lesser of:
    (a) a speed of at least:
    (i) for a car with special features for off-road use—140 kilometres an hour; or
    (ii) for another car—180 kilometres an hour; or
    (iii) for another motor vehicle—120 kilometres an hour; and
    (b) the vehicle’s top speed.

    This means that an vehicle for off-road use (ie a 4WD) can have tyres rated as low as 140km/hr (or N speed index). Of course that mean that you cant drive faster that that.

    The speed rating of the tyres fitted to vehicles for off-road must be of at least 140 km/h (‘N’) when the tyre placard requires a higher speed rating than ‘N’.

    Darryl McManus of Adelaide Posted on 06 November 2013 4:32pm
  • Not quite right - there are differences for 4wds and other vehicles as per below.

    “Replacement tyres must have a load rating equal to or better than the minimum load rating stated by the vehicle manufacturer on the tyre placard.

    In addition, there is a minimum requirement for a replacement tyre’s speed rating (unless the tyre placard specifically allows a lower rating). In NSW that is 140km/h for all vehicles, plus a warning label must be fitted if the replacement tyre has a speed rating lower than the minimum required by the tyre placard. In all other states and territories it is 180km/h for passenger cars, 140km/h for off-road vehicles and 120km/h for other vehicles.”

    Peter of Dural Posted on 07 January 2013 11:23pm
  • I think you should check your facts.I might be wrong but I believe that a car is supplied by the carmaker with a certain speed rated tyre fitted will have a tyre placard stating the speed rating and if you fit a less rated tyre the car won’t be roadworthy in your state.If you drive an unroadworthy car and have an accident you might not have insurance and also liable for infringement notice by the police or a law suit if a person was injured.Your comment when check would be appreciated.

    David of Queesland Posted on 20 January 2012 10:58pm

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