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  1. #511
    Senior Member AnttiL's Avatar
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    I'm also interested in the cross tyre setup. What are the pros and cons? I understand the drivers have a limited amount of tyres per rally so sometimes that's what they have to do. But how much does the diff balance it out?

  2. #512
    Senior Member Revman's Avatar
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    Quote Originally Posted by AnttiL View Post
    I'm also interested in the cross tyre setup. What are the pros and cons? I understand the drivers have a limited amount of tyres per rally so sometimes that's what they have to do. But how much does the diff balance it out?
    Yes, and what is the thinking? For example, a softer tire goes to which wheel on a four wheel drive race car under what circumstances (surfaces)?

  3. #513
    Senior Member Mirek's Avatar
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    Quote Originally Posted by AnttiL View Post
    I'm also interested in the cross tyre setup. What are the pros and cons? I understand the drivers have a limited amount of tyres per rally so sometimes that's what they have to do. But how much does the diff balance it out?
    If I remember right it was Juho Hänninen in 2011 Monte Carlo who used it first (or at least it was first widely discussed case) when Škoda team (and Petter Solberg) fucked-up tyre choice and lost the fight for victory there. He used it out of necessity and it worked much better than let's say two winter tyres in front and two slicks in the rear.

    I believe the main rationale lies in the fact that limitted-slip differential helps to bring overall grip level of the axle closer to the level of the better wheel. In that case an axle with only two wrong tyres benefits in no way from having LSD in between. Therefore if You have two better tyres it's better to place one in front and one in the rear (cross) and by that enhance a bit the grip on both axles instead of having one good and one useless.
    Stupid is as stupid does. Forrest Gump

  4. #514
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    its just that 2 good wheels on the front give to much oversteer, and 2 good wheels on the back too much understeer. so they use on wrong wheel and 1 good wheel on each axle, which gives a more stable feeling.
    the only reason they do that is because they can't carry for spares in the boot.

  5. Likes: A FONDO (3rd January 2018)
  6. #515
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    some close photos from yaris and new canards and front wing from https://twitter.com/Traxx_WiF/media




  7. Likes: EstWRC (4th January 2018),Mirek (4th January 2018),pantealex (4th January 2018)
  8. #516
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    Those are still prototype parts, just saying
    "quattro best 4wd rallycar ever"

  9. Likes: EstWRC (4th January 2018),Mirek (4th January 2018)
  10. #517
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    When do the current WRCar regulations run until?

  11. #518
    Junior Member Mrpengski's Avatar
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    Quote Originally Posted by Revman View Post
    Thank you for this reply. Tremendous. Do you see any trends regarding the aero (given that this is what we can see)? I read on one site that Toyota may have narrowed the front bodywork, revised the "grill" area, and added an upper dive plane to offset the massive wing. All speculation, or do you think this is a legit analysis?
    Agree on all points. Now that more detailed pictures are showing up online, it's even clearer what they did. I particularly like the outlets towards the side of the car on their new front bumper. Pre-2017 cars all had this type of openings on the side, which help manage the air around front wheels. For 2017, the tech reg didn't appear to allow this treatment at first... But clearly with some clever thinking, it's still possible. Good for them! There are other details which are probably very difficult to photograph. Maybe they got some help from the aero department in Cologne?

  12. #519
    Junior Member Mrpengski's Avatar
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    Quote Originally Posted by Mirek View Post
    If I remember right it was Juho Hänninen in 2011 Monte Carlo who used it first (or at least it was first widely discussed case) when Škoda team (and Petter Solberg) fucked-up tyre choice and lost the fight for victory there. He used it out of necessity and it worked much better than let's say two winter tyres in front and two slicks in the rear.

    I believe the main rationale lies in the fact that limitted-slip differential helps to bring overall grip level of the axle closer to the level of the better wheel. In that case an axle with only two wrong tyres benefits in no way from having LSD in between. Therefore if You have two better tyres it's better to place one in front and one in the rear (cross) and by that enhance a bit the grip on both axles instead of having one good and one useless.
    Interesting. The cross tyre setup was a new concept for me when I joined WRC. I do recall the WRC TV commentators were discussing the merits of left-to-right mix, instead of cross. Apparently this could give them more confidence because the car will behave more predictably, albeit at different grip levels left and right.

  13. #520
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    Quote Originally Posted by RS View Post
    When do the current WRCar regulations run until?
    "The principles of the technical and homologation regulations for the 2017-2019 WRC car were approved by the World Motor Sport Council."

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