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Why are car tyres not symmetrical?

  1. May 8, 2008 #1
    When I was changing my car's tyres I noticed something I can't explain: I assumed that the left two tyres should be a mirror image of the right two tyres: therefore they should be different. However it is not so: all four tyres are identical, so it is impossible to place them symmetricaly.
    Does anyone know what is the reason why car tyres are not symmetrical with respect to the central plane of the car?
  2. jcsd
  3. May 8, 2008 #2


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    Because then you would have left and right hand side tires, hence companies would have to make and stock twice as many tires.

    There is such thing as directional tires (the must be installed in such a fashion to make sure they spin in the correct direction), but I can't think of any reason why you would want your tires to be made such that you would have different tires on the right and left sides of the car.
  4. May 8, 2008 #3


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    How about


    I mean...


  5. May 8, 2008 #4


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    Maybe it's to match up with those left-hand threaded lug nuts from the other thread...
  6. May 8, 2008 #5
    Asymmetric tires do exist -- the Goodyear Eagle F1 and Yokohama Parada are the only current models I know:

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  7. May 8, 2008 #6


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    There's no doubt that they exist. I believe that the OP question relates to whether or not they're worth the price for a normal vehicle. I'd have to vote 'no' on that. I'd replace the defective ones with 'universal' patterns, and repeat until your originals are used up.
    That's using North American standards, though. If you're going to be cutting loose on the Autobahn, something more stringent is required.
    Last edited: May 8, 2008
  8. May 8, 2008 #7


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    I think the OP's question is probably simpler....

    Notice that the labels are pointed out on both sides of the car: they are mirror images of each other and symmetric to the central plane of the car!
  9. May 11, 2008 #8
    I have also checked my winter tyres and found out that they can (and must) be placed symmetricaly, since they have left and right version, which are the mirror image of each other. Obviously it is possible to create a tyre that works better when rolled in a certain direction. The direction is probably important to better push the water away: the V shaped channel always points in the rolling direction, so that it first touches the ground with the lower part of V (in the center of the tyre). I suppose this allows water to flow of in the direction it is naturaly pushed (forward and aside).
    However my summer tyres are not symmetric to the central plane of the car: at least if one also considers the direction of transversal channels, which are inclined up (as they ran from outer edge of the wheel towards the interior) on one side and down on the other side (if viewed from the front of the car).
    Maybe the effect of directed channels is not that important for summer tyres, since they are not supposed to encounter so much bad weather.
    Last edited: May 11, 2008
  10. May 11, 2008 #9
    Yes there are tires that are not symmetric, and one application is used for track racing.

    Cars have adjustable camber (which is one aspect that gets adjusted when getting an alignment).

    Because of this you can have negative or positive camber (which is basically the angle the tire makes from the [] view to the car (not the side of the wheel)).

    This is so you can adjust where the maximum grip is for the tires. This is useful for making turns through corners at high speeds and being able to gain more grip.. which is why the tires end up eating grip in an odd fashion in these track cars.

    I used to race my car, and my tires are not symmetrical. They have to be rotated in a specific direction because it only goes one way. I have Falken Ziex-912s and they grip real well for street tires. Mainly for sport applications though, not driving in snow or whatevers.
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