Use of 'summer' tyres below 7 degrees

Discussion in 'Wheels, Tyres, Brakes & Suspension' started by BTB 500, Oct 16, 2011.

  1. BTB 500

    BTB 500 MB Club Veteran

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    It's been repeated many times here that winter tyres out-perform summer tyres below 7C on good road surfaces due to the softer rubber. Some have been less than convinced by this rather vague claim, wanting more specific details of compartitive braking distances at different temperatures. So I was interested to see the recent What Car? test of winter tyres vs summer tyres.

    Specifically the bit that said when they measured dry stopping distance from 62 mph at 5.5C (NB - below 7C ;)), the winter tyres took an average of 19 feet more to come to a halt ...

    In fact even the worst summer tyre (Nankang) outperformed ALL the winter tyres:

    [​IMG]
     
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  2. steve333

    steve333 Hardcore MB Enthusiast

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    We've had a couple of consecutive winters where snow has fallen/temperatures have been low for longish periods & all of a sudden tyre suppliers are pushing winter tyres-i wonder why!
     
  3. Dieselman

    Dieselman Banned

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    ^^ The above makes sense as the Winter tyres have larger sipes and less rubber, but the blocks move around more.

    They are designed to grip snow.

    Thanks BTB.
     
  4. OP
    OP
    BTB 500

    BTB 500 MB Club Veteran

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    I don't think anyone disputes that winter tyres have a big advantage on snow. I personally doubted the claims about them being better than summer tyres as soon as the temperature dropped below 7C though, and the What Car? test (which is obviously independent i.e. they're not trying to sell tyres) seems to bear this out.
     
  5. cuprastu

    cuprastu Member

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    So then are winter tyres a waste of time? I was thinking of getting some as my car is useless in the snow, but it could do with new tyres, so do you think getting just new decent summer tyres will make it better in snow?
     
  6. cuprastu

    cuprastu Member

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    Sorry about my reply, the others above came in while typing mine!
     
  7. wemorgan

    wemorgan MB Club Veteran

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    Interesting article, thanks.

    I feel that if motorists only had to deal with cold weather then winter tyres wouldn't be spoken about, regardless of the claims on either side. It's their ability in snow that's of primary importance to motorists IMHO.
     
  8. steve333

    steve333 Hardcore MB Enthusiast

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    Fair comment Will,for the amount of lying snow we get each year i personally won't bother with winter tyres(i would rather leave the car on the drive for a week or two each year & let my front wheel drive van battle through it!:eek:;)).
     
  9. cuprastu

    cuprastu Member

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    I had thought about getting a cheap front wheel drive banger for winter to save the w202 getting rusty.
     
  10. steve333

    steve333 Hardcore MB Enthusiast

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    Would be cheaper than getting a set of winter tyres for the w202!
     
  11. wemorgan

    wemorgan MB Club Veteran

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    Very old ground I know. A set of second-hand steel wheels/alloys can be bought very cheaply + winter tyres are not always more expensive than summer ones. You only wear out one set at a time, so the on-cost is just the wheels. So it need not cost a lot to kit yourself out with winter tyres......it's more about personal preference :)
     
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  12. moonloops

    moonloops MB Club Veteran

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    Statistics are all very fine and dandy.

    Just drive with respect for the conditions and tyre choice
     
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  13. Mercy1

    Mercy1 Hardcore MB Enthusiast

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    We seem to be going round in circles with winter tyres - typical I suppose when it comes to statistics/surveys etc.
    But I think it is generally acknowledged that there is a compromise in any choice.
    Personally, I would rather be more careful on my winter tyres driving in dry weather than totally stuffed driving on summer tyres in snow. That is why my winter wheels will only go on when it gets really cold.
    Very little is ever mentioned about icy or frosty roads - yet these conditions are much more prevalent in winter than thick snow. No mention in the surveys. Are all tyres useless in such conditions??
     
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  14. steve333

    steve333 Hardcore MB Enthusiast

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    It matters not what tyres you have when thick/black ice is on the road,more a case of adjusting your driving to the conditions.
     
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  15. Spinal

    Spinal Hardcore MB Enthusiast

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    Interesting!

    Especially as I had the UltraGrips on the W202 (they came 2nd or 3rd in the german tests) and was VERY impressed by them...

    I guess I'll delay fitting winters until I see snow then! Oh wait, too late for that :p
     
  16. Doodle

    Doodle Hardcore MB Enthusiast

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    I suspect the gap will close up in the wet, c/o better water clearance and retained heat.

    But in the dry, this was inevitable.
     
  17. OP
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    BTB 500

    BTB 500 MB Club Veteran

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    In the wet at 4 degrees C the winter tyres do show an advantage in straight-line braking, but it's not huge:

    [​IMG]




    Interestingly they also did a 'wet handling' test at 5 C, which a summer tyre won. Continental say that the point at which a winter tyre has the advantage is 2 C (rather than the widely quoted 7 C)
    Looking at those results the biggest point seems to be - avoid budget tyres!
     
  18. grober

    grober MB Club Veteran

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    Not disputing what you say but your post could be a bit misleading for the un-initiated since if you read the report in full the winter tyres outperformed the summer tyres in almost every other condition. One grey area was aquaplaning where a side-stepping grippy tread pattern instead of continuous grooves round the tyre circumference would not clear water so quickly in a straight line is fairly predicable. Similarly on a dry road surface greater movement due the increased tread depth and higher void to tread surface ratio of winter tyres would result in longer stopping distance could be fairly readily deduced from first principles. On dry pavement presumably grippy racing slicks would prove to be even better not to mention illegal?:doh: I assume also that as all the tyres wear down the winter tyres with their initial greater tread depth would improve in the dry somewhat as tread depth reduced. The summer tyres performance would degrade even further in the snow,ice and wet of course . I think the thing to take account of is the performance over the life of the tyre and in typical road conditions found in the British Isles over the colder months. I believe the survey comes to the same conclusion despite the "exception to the rule" situation you are quoting.
    the article's conclusion:-

    Our tests prove that winter tyres offer big safety benefits over their summer equivalents – not only in snowy and icy conditions, but also in the wet when the temperature dips below 7C.

    For that reason we’d urge all drivers to consider swapping to winter tyres for the coldest months of the year – the six months recommended by many tyre manufacturers are sensible only in colder parts of the UK. Depending on the severity of the winter, drivers in more temperate regions – such as the south of England – may be better off on summer tyres for up to nine months of the year.


    As an aside, one disadvantage of the high silica content of winter tyres is they are evidently more susceptible to UV light rubber degradation of the sidewalls [ I have noticed this myself actually] While not a problem the higher carbon black content of summer tyres [ the stuff that makes them inflexible under 7 C:(] makes them more resistant to this type of damage.
     
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  19. markjay

    markjay MB Club Veteran

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    Winter tyres tested - Wet conditions - Car and Car-Buying News - What Car?

    Good one, thanks BTB 500.

    I think that the 7 degrees is just an arbitrary figure really. I accept that summer tyres' performance deteriorate with temperature, but I suspect that the exact point at which the winter tyres out-perform summer tyres is different from one manufacturer another, as can be seen by this statement:

    'Continental says in-house tests have shown its winter tyre outperforms its summer tyre below around 2C.'
     
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  20. Dryce

    Dryce MB Club Veteran

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    Intersting post. Thanks. WC have actually tried to provide some meat compared with the usual rather more opaque articles on the subject.

    I wonder what the numbers would be like for salted wet roads and dried out salted roads.
     

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