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LRR tyres Europe.

Discussion in 'Gen 2 Prius Fuel Economy' started by Britprius, Feb 6, 2013.

  1. Britprius

    Britprius Senior Member

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    Thought I would post some pertinent facts about the UK/EU tyre test and what they mean as far as tyre performance is concerned. As you may know tyres are now put through a strict standard test and graded for rolling resistance (RR) and wet grip (WG) in 7 grades labeled A to G,
    A being the best G the poorest.

    For RR the difference between any two adjacent grades in fuel consumption terms is given as between 2.5% and 4.5%. This is a difference in the UK of between 1 and 2 MPG for each increase or decrease of grade letter or an overall difference between A and G a minimum of 7 MPG and a theoretical maximum of around 15 MPG.

    For WG the difference between any two adjacent grades at 50 MPH is given as a stopping distance difference of between 3 and 6 metres (10ft and 20ft) this could represent a difference in braking distance at 50 MPH between An A rated and G rated tyre of between 21 and 42 metres (70ft to 120ft)

    Tyre noise is also graded as one, two, or three bars. One bar being the quietest at below 69DBa, two bars runs from 70 to 72DBa and above that is three bars. Future regulation will mean the maximum noise level will come down to two bars 72DBa.

    For snow tyres under future regulations 1DBa extra will be allowed.

    John (Britprius)
     
    #1 Britprius, Feb 6, 2013
    Data Daedalus and uart like this.
  2. uart

    uart Senior Member

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    It's interesting that the percentage difference in FE is that large John. I love the idea of manufactures having to really quantify LRR like this. The fact is that people are making decisions on what tire to buy based on descriptions like "low rolling resistance" or "ultra low rolling resistance". And currently in Australia it's a bit like flashlight batteries saying "heavy duty" versus "ultra heavy duty" or "extra heavy duty" etc, without something quantifiable like mA-hrs it can become almost meaningless.

    I really hope Australia follows suite and introduced similar mandatory grading here as well.
     
    #2 uart, Feb 6, 2013
  3. Britprius

    Britprius Senior Member

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    Yes I agree. I did not expect the differences to be that great, but those are the official figures.

    The stopping distances really make you sit up and take notice.

    It would be help full if zinc carbon and alkali batteries or even the none chargeable lithium were sold with ratings along the same lines as tyres and white goods. Maybe this will happen. The only batteries "apart from vehicle" that are marked with capacity are rechargeable types.

    John (Britprius)
     
    #3 Britprius, Feb 6, 2013
  4. GrumpyCabbie

    GrumpyCabbie Senior Member

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    Should be simple to introduce as I know your emissions are based on the Euro versions. Saying that, don't your tyres have to be different to ours to handle the intense heat? I remember having some JDM tyres on an imported MR2 which were ridiculously hard and deadly in the wet.

    It is a good system though as I will now be using it on my next tyres. It's the same as when they introduced the same system in white goods. Many fridges rated E or G but now it's hard to find one below a B and I think washing machines now have A+ and A++ for energy efficiency ratings.
     
    #4 GrumpyCabbie, Feb 6, 2013
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