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Suspension Performance and Head Angle

Discussion in 'Downhill & Freeride' started by 93dls, May 10, 2013.

  1. 93dls

    93dls Chimp

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    Recently i went from a 63.5º to a 63º head angle both using an angleset 0.5º and 1º respectively. The only downside i've noticed is a decrease in small bump sensitivity and less sag when using the same for settings. When i pedal on the flat my forks don't move at all even with no lsc and during in a car-park bounce test you can feel that the force isn't being transferred into the suspension but instead directly downward through the handle bars. The suspension reacts the same on trail hits its more that your body weight has less effect on it. If that makes sense.

    So my question is has anyone else notice a change in suspension performance as head angles get slacker?

    Next ride i am going to play around with handlebar roll to see if that makes a difference. The only other thing that could be the problem is maybe my forks could use a full service but i'm hanging out till just before i fly to whistler to do that.

    My average fork setting, rider weight 76kgs getting about 20% sag
    Boxxer world cups 2013
    50psi with 3 turns of bottom out
    4 lsc
    4 hsc
    7 bsr
    6 esr
     
    #1 -   May 10, 2013
    Last edited: May 10, 2013

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  2. sethimus

    sethimus scroll all you want!

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    easy, ride steeper tracks. problem solved.
     
  3. Mr Nug

    Mr Nug Monkey

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    You shouldn't be able to detect that much difference in 0.5 degrees... Theoretically you should use less air pressure to achieve the same sag as before and perhaps more compression damping for absorbing hits but at half a degree it should be very subtle.
     
  4. tabletop84

    tabletop84 Monkey

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    Check dem bushings and lubrication.
     
  5. jonKranked

    jonKranked Press Button, Receive Stupid

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    check the x vector, yo
     
  6. 93dls

    93dls Chimp

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    Cheers

    Lower legs are fine. Fresh fluid and slick honey one ride ago.

    Yeah i am also skeptical. Might just have to change a few setting to get a more supple beginning stroke. On a side note i did crack and bend my old frame next to the head tube whilst running 0.5º angleset
     
  7. jonKranked

    jonKranked Press Button, Receive Stupid

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    0.5° moves the front axle forward something like 4mm, so not that much
     
  8. Mr Nug

    Mr Nug Monkey

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    Did you do the short term "negative air trick" on the damping leg when you did this? (Before you put the footnut on, compress the fork to get the air out of the lower legs).

    Can't think of any other reason why you'd notice such a big difference unless something has gone wrong internally
     
  9. bizutch

    bizutch Delicate CUSTOM flower

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    I swapped my same fork out from my 08 DHR with 64 degree head angle to my 2011 DHR with 63 degree head angle. I could tell the same thing. When you're running on shallower track, especially over roots, you can definitely notice less sensitivity to small, rigid trail features.

    The head angle definitely is what caused this. I don't think you should do ANYTHING to change your damping or sag settings because of it. It's the trade off of the slackness for high speed and the fork will function as normal when the trail tilts steep, which is far more important.

    You just have to live with it.
     
  10. aenema

    aenema Monkey

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    the slacker you go, the more you are laterally loading your bushings on the fork on flat terrain. Like others say, when you point down the steep stuff this is no longer an issue. You will notice on the flats, for sure, the loss of subtleness but if the trade-off is with it on the trails you actually ride, don't fret.
     
  11. kidwoo

    kidwoo Celebrating No-Pants Day

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    Damn other people do that too? I thought I was a friggin genius when I started doing that a few years ago. :rofl: Probably foams up damper fluid sooner but it does help some forks for sure.


    Yes changing your headangle changes everything about how your suspension works. It changes the angle of attack on both devices (frame and fork) just like everyone's saying. Yeah half a degree is pretty minor but if there's anything to ever be gleaned from all the bike geeking here, it's that sublte changes do make a difference.

    Preload and damping are easy to mess with. If your bike doesn't feel like you want it to just mess with it. Tires/bar angle etc. all equal, you DID change how your bike works, even if it's just a little bit.
     
  12. time-bomb

    time-bomb Monkey

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    I would also encourage you to remove one or more of your forks from the bike. Only one is necessary and generally there is enough adjustment range in any fork that you would only need one to find the right setting. The others are just adding unnecessary weight.
     
  13. 4130biker

    4130biker PM me about Tantrum Cycles!

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    That's the first thing I thought- especially being a boxxer (not hating, I love by boxxers forks.)
     
  14. Kanye West

    Kanye West 220# bag of hacktastic

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    It sure does. Open bath forks are a cavitating mess until a certain position in the travel where there's enough pressure to make the fluid consistent again. By doing the negative air trick, that position happens later.

    If your fork is old and the bushings are worn a little bit, the head-angle related binding will become more prevalent.

    And yeah, just ride steeper trails. I can't imagine small bump performance on flat trails is paramount for a 63 degree HA bike.
     
  15. WestCoastHucker

    WestCoastHucker Turbo Monkey

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    his extra handlebar is also more unnecessary weight...
     
  16. kidwoo

    kidwoo Celebrating No-Pants Day

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    Not sure I buy that it's something appreciable on a normal 3-4 minute run though on a 1:1 device like a fork. It certainly never affected rebound damping where it would be the most obvious. I wonder how much pressure drop you could actually generate over a 30mm by whatever that cavity is (8 inches?). Damper fluid off gasses anyway so it never lasted that long. That's actually why I started doing it, to prolong 'burp' intervals.
     
  17. Kanye West

    Kanye West 220# bag of hacktastic

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    It occurs on the very first few cycles and would be most noticeable in compression consistency. It's a lot harder for those air bubbles to work themselves in through the compression valve, through the main piston and behind it, then to be felt on the rebound stroke.
     
  18. kidwoo

    kidwoo Celebrating No-Pants Day

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    Considering how overdamped RS forks are with everything dialed all the way out on the compression stroke bits, no wonder I never noticed it. Win/Win! :D

    Didn't screw up my rebound damping so I kept doing it.
     
  19. Wa-Aw

    Wa-Aw Monkey

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    My sarcasm meter is having a hard time with the "overdamped" there.

     
  20. Kanye West

    Kanye West 220# bag of hacktastic

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    Fixed that for you.
     
  21. kidwoo

    kidwoo Celebrating No-Pants Day

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    Okay, no one got the joke.

    Sticky.

    Lubed up, sanded, covered in oil, damping is completely useless because all the way off my wrists still hurt from pebbles still doesn't fvcking move when it's suppoed to sticky.

    Fvcking sticky.

    Better? :D


    edit: headangle....yeah changes things, change suspension things. It's only butch that told you not to. That should tell you something.
     
    #21 -   May 11, 2013
    Last edited: May 11, 2013
  22. curtmuss

    curtmuss Chimp

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    i hear/have heard that you need to soften things when you go slack.....
     
  23. GekoES

    GekoES Chimp

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    Not if you're going downhill...
     
  24. kidwoo

    kidwoo Celebrating No-Pants Day

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    I heard somewhere that if you change something on your bike, you should go ride it.

    And then adjust accordingly.

    Not sure how much truth in that though.