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MotoGP | 2019 | Round 4 | España| Jerez | May 3 - 5

Discussion in 'General' started by BigBird, Apr 29, 2019.

  1. Metalhead

    Metalhead Dong pilot

    Oh great. The engineers ate here. I'm going for a nap.
     
  2. Steve H

    Steve H Well-Known Member

    Something very much like that. Look at the front end of a Britten - there are no round fork tubes. Instead it has rectangular carbon fiber beams. Quite strong and rigid in the length direction of the motorcycle to take braking loads - much more flexible in the sideways direction for when it hits a bump while leaned over.

    I don´t know what you do to a carbon fiber composite to provide internal damping. But a few years ago a guy who worked in the field told me this technology was developing as a result of carbon fiber being used in prosthetics. He also mentioned issues with poor U.V. resistance.
     
  3. eggfooyoung

    eggfooyoung You no eat more!

    "You got lucky, babe!"
     
  4. pickled egg

    pickled egg Tell me more

    Don't be petty
     
  5. eggfooyoung

    eggfooyoung You no eat more!

    You better watch what you say.
     
  6. pickled egg

    pickled egg Tell me more

    You think you can do me like that?

    Well, don't. :moon:
     
  7. Steeltoe

    Steeltoe What's my move?

    Lawd geezus lawd.
     
    pfhenry likes this.
  8. fastedyamaha

    fastedyamaha Well-Known Member

    Let’s get back to racing and the smack down laid down by Marky Mark and the bad luck of Quartaro...
     
    BigBird likes this.
  9. Steeltoe

    Steeltoe What's my move?

    I need a valium. 2nd in the championship!

    [​IMG]
     
    ShadowBoxer and pfhenry like this.
  10. Ra.Ge. Raptor

    Ra.Ge. Raptor wanna_be_fast

    Rins is a regular podium finisher. Of course he's 2nd... MM93 is untouchable. Again. There's fight for the 2nd best (icymi :D )
     
  11. HPPT

    HPPT !!!

    Doesn't the rigidity depend on the direction in which the strands are layered? And if so, couldn't they be made stiffer or softer than the aluminum forks depending on what's needed?

    I'm also curious what it does to front end feel. It wasn't too long ago that Ducati abandoned their carbon fiber frame because of feedback issues.
     
  12. gixxerboy55

    gixxerboy55 Well-Known Member

    Wouldn't it be the inner tubes that would be giving feel not the outside tubes, as they are just sliding up and down.
     
  13. Phl218

    Phl218 .

    I think the old doc frame had to work in all directions with short distances between bolt-ons, so ultimately too rigid.

    Way easier to modulate over longer distances or less directions
     
  14. Ra.Ge. Raptor

    Ra.Ge. Raptor wanna_be_fast

    The main problem with carbon is that when it bends, it returns in its previous position too sharply, in contrast to aluminium. Sure they'll find a way to make it respond like the aluminium, if they haven't already.
     
  15. fastedyamaha

    fastedyamaha Well-Known Member

    Does Jorge have a 2 year contract? Pretty bad to get beat by a test rider doing a wild card race.
     
  16. pfhenry

    pfhenry Well-Known Member

    orientation of the fibers does matter...
    and how many layers in that specific orientation...
    and autoclave pressure
    and the resin itself.. biggest factor
    i'm assuming they are using aerospace grade carbon as well

    obviously metal inserts are needed with carbon... but is it a regular fork tube outer wrapped in carbon or something totally different.... the world may never know

    hard to say if their goal was more/less flex or less weight depending on all these variables...

    also thats the old carbon fork in last picture
     
  17. tzrider

    tzrider CZrider

    One would think that you would want the fork assembly to be as rigid as possible since it's a sliding device. Any bending impedes the movement of the forks.

    Any flex would be designed in the stem to frame structure.
     
  18. pscook

    pscook Well-Known Member

    Until you are leaned over at 50+ degrees, then the forks no longer slide and need to flex in a lateral(ish) direction. More deflection than flex, I think? I used a pair of carbon bars on my GasGas 300 (okay, aluminum core with carbon outer) that KILLED the engine vibes and helped me to feel the suspension move. I know that if I had kept those bars that my suspension settings would change to allow me to finally feel the front end. I assume that road bikes are different than off road as off road is almost all vertical whereas road racing would rely on when it's tipped over in the middle of a turn and you experience a ripple in the racing surface. I think that the carbon swingarm is similar in the lateral flex department. The shock will handle the vertical, but when you get to a certain point of lean the forks and shock stop moving in their active plane.
     
  19. Phl218

    Phl218 .

    I held those Ö tubes in my hand . Carbon only. Weigh nothing.
     
    Steeltoe likes this.
  20. SPL170db

    SPL170db Trackday winner

    You have to think beyond just the forks sliding up and down. The outer tubes are what is clamped to the rest of the bike, and the fulcrum point where they would bend under load. The tubes themselves bend/flex when something other than a straight up and down force is exerted on them.

    The further leaned over the bike gets from upright, the less and less the actual suspension stroke of the forks and shock are working and the more and more the engineered flex of the chassis components comes into play.

    This graphic displays it in regards to the swingarm, but the same principles are in play on the front end.

     
    YamahaRick, Rebel635 and Phl218 like this.

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