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I Is there so-called "optimal traction" for vehicles?

  1. Aug 28, 2018 #1
    Consider for vehicle, a low traction indicates a lower road grip, which leads to a skid easier; a high traction makes the vehicle difficult to steer, and also damages both road and tire.

    So I am wondering if there is a balance point of the traction in vehicle design such that it is at an optimal state?

    Free feel to point out anything i got wrong above. Thanks.
  2. jcsd
  3. Aug 28, 2018 #2


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    Hello and welcome to PF.
    Compromise is the key word here.
    For a given wheel and tyre size, a huge factor governing traction is the tyre material. The material for a domestic vehicle tyre is a compromise between adequate grip and tyre life. The optimum for a racing tyre is different. They are expected to wear out within the time of a single race because they need very good grip.
    Then there is the compromise for driving conditions. On a dry track, slicks give best traction (no tread) but when there is any water on the track, a grooved tread is needed to push water aside and give a good contact with only half the area.
  4. Aug 28, 2018 #3


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    Yes, high traction can result in a fragile tire. The compound used in racing tires is soft and sticky. Crumbles can peel off of it.
    Yes, high traction can result in road damage. Putting studs or chains on a snow tire can result in road damage.

    It is not clear that there is serious motivation to trade away good grip to gain easier steering, however. Can you give an example?
  5. Aug 28, 2018 #4


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    There is not one optimum. It depends on the vehicle's task. For normal consumer cars fuel consumption is a major issue.
  6. Aug 28, 2018 #5


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    Optimal requires a value judgement for "best". Clearly, a government dealing with highway repair budget, will disagree with salesmen of studded tires, about how to define "best".

    Even for individual people, the trade-off between performance and price is not something that everyone will agree on.
  7. Aug 28, 2018 #6


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    An example would be steering while the car is stopped. But I also don't think that this is a relevant consideration.
  8. Aug 28, 2018 #7
    Thanks for your answers.
    So could i say "we always want a higher traction for cars to grip the road and prevent skidding. And if this traction is high enough to hinder motions(e.g. hard to steer), we would consider other approach to overcome this problem(e.g. Power steering), instead of decreasing the traction"?
  9. Aug 29, 2018 #8


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    High traction doesn't make a car difficult to steer if the car is moving. For public roads, the main case I can think of for steering while a car is stopped is part-way through a parallel parking sequence, and it's unlikely to put much wear on the road or tires. If you look at asphalt roads that show signs of wear, the main locations of deformation are at intersections, due to braking and acceleration. You don't see this type of deformation on streets with parallel parking.
  10. Aug 29, 2018 #9


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    Didn't we just explain to you, that this is not a relevant issue?
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