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Thread: Bike ‘weaving’ under heavy braking on track

  1. #21
    Forum Moderator alex's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Quote Originally Posted by Ma Salope View Post
    Hi I had the same on my 2011 on track, fitted Ohlins cartridge kit and all the weaving stopped. You prob need heavier springs in forks. But my advise it go for a cartridge kit with springs for yr weight .
    Think he's just bottoming out too fast?

    - Alex

  2. #22
    Standard Member cropsprayer's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Quote Originally Posted by alex View Post
    Think he's just bottoming out too fast?

    - Alex
    Sorry for another question on this Alex but your previous post said to add some rear rebound which I get will slow the weight transfer forward and hence stop the front diving so quickly. If I add more compression to the front would that not have the same effect? If so how do you decide best which adjustment to make where?

    like I say apologies for the additional question it will just help me with my understanding more on the suspension side. Also just for info I have Öhlins front and rear suspension on the bike.

  3. #23
    1 YEAR PREMIER MEMBER bmwbadboy's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Quote Originally Posted by cropsprayer View Post
    Sorry for another question on this Alex but your previous post said to add some rear rebound which I get will slow the weight transfer forward and hence stop the front diving so quickly. If I add more compression to the front would that not have the same effect? If so how do you decide best which adjustment to make where?

    like I say apologies for the additional question it will just help me with my understanding more on the suspension side. Also just for info I have Öhlins front and rear suspension on the bike.
    if you want to stop weight transfer to front, you want to do both. in addition to that, you want to increase comp in rear as well.

    also, I would zero (or decrease) preload on rear.

    btw, front zip tie should be in region of 15-20mm, not 10.
    Last edited by bmwbadboy; 16th July 2018 at 10:14 PM.

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  5. #24
    Forum Moderator alex's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Increasing rear rebound slows the action of the rear shock expanding. Which stops the rear ejecting you out of the seat...and therefore the weight of the bike forwards.

    Obviously this won't stop weight transfer but it may allow you to get more braking done before bottoming because you come in flatter and you keep the rear on the deck longer.

    (Which mode disables the combined front and rear brake btw? Anyone? Slick only or Slick and Race).

    Compression on the front slows the dive but if the springs aren't hard enough then nothings gonna stop you hitting the bottom.

    Preload is best for trying to stop the forks smashing flat with the springs you have. Bottom is 8mm above casting. I would aim for 15mm above for a safety margin for the 'oh f**k' moments.

    Every adjustment is a trade off.
    Change one thing per test.

    What do you weigh kitted and what are the spring rates fitted?

    - Alex

  6. #25
    1 YEAR PREMIER MEMBER bmwbadboy's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    In addition to what Alex wrote above,

    the best indicator of whats wrong or whats not wrong, is not your human senses, but the tires (especially if you're running slicks).

    Look at tire wear after every session and if they dont look like a sandy beach sand, immediately question your suspension/pressure settings.

  7. #26
    Standard Member DrIoannis's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Do you have ABS on while you are in the track? If you do then turn it off and try again. I turn ABS off in the track because I had the same feeling you describe.

  8. #27
    Standard Member Ma Salope's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Quote Originally Posted by DrIoannis View Post
    Do you have ABS on while you are in the track? If you do then turn it off and try again. I turn ABS off in the track because I had the same feeling you describe.
    Will have nothing to do with ABS, it's down to set up.

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  10. #28
    Standard Member cropsprayer's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Quote Originally Posted by alex View Post
    Increasing rear rebound slows the action of the rear shock expanding. Which stops the rear ejecting you out of the seat...and therefore the weight of the bike forwards.

    Obviously this won't stop weight transfer but it may allow you to get more braking done before bottoming because you come in flatter and you keep the rear on the deck longer.

    (Which mode disables the combined front and rear brake btw? Anyone? Slick only or Slick and Race).

    Compression on the front slows the dive but if the springs aren't hard enough then nothings gonna stop you hitting the bottom.

    Preload is best for trying to stop the forks smashing flat with the springs you have. Bottom is 8mm above casting. I would aim for 15mm above for a safety margin for the 'oh f**k' moments.

    Every adjustment is a trade off.
    Change one thing per test.

    What do you weigh kitted and what are the spring rates fitted?

    - Alex
    The bike had the Ohlins front forks when I bought it and the springs fitted are set for 84KG to 89KG without gear. I'm 80KG without gear. It say the springs are 10.5/11.0 Nmm springs.

  11. #29
    Standard Member cropsprayer's Avatar
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    Re: Bike ‘weaving’ under heavy braking on track

    Quote Originally Posted by bmwbadboy View Post
    In addition to what Alex wrote above,

    the best indicator of whats wrong or whats not wrong, is not your human senses, but the tires (especially if you're running slicks).

    Look at tire wear after every session and if they dont look like a sandy beach sand, immediately question your suspension/pressure settings.
    Thanks, my tyre wear has always been good on this bike and no 'bands' or chewed up rubber like I see running through other peoples. I have an Ohlins rear shock that I bought new and Harris set it with 'standard track settings' which I have never altered. Mainly because I don't like messing with something that I thought wasn't giving me an issue when I am far from being a suspension expert :-)

  12. #30
    Forum Moderator RyS1000RR's Avatar
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    Suspension Setup

    Quote Originally Posted by cropsprayer View Post
    ...'standard track settings' which I have never altered. Mainly because I don't like messing with something that I thought wasn't giving me an issue when I am far from being a suspension expert :-)
    Suspension setup is a continually evolving process. The bike will behave differently as your pace increases so you can never just rely on ‘standard track settings’. All they provided you with is a base setting from which to work from and improve. The next time you are on track just speak to the suspension technician there and they should be able to help translate your ‘feeling’ on the bike into meaningful adjustments which will help you.

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