Front End bottoming out

Discussion in 'General' started by Nytrozula, Aug 27, 2019.

  1. Nytrozula

    Nytrozula Well-Known Member

    Teh zip tie on my front forks is consistently at the very bottom of the shock. I'm sure I need a stiffer spring but until I get some can I add more preload to keep the front shock from bottoming out? And does preload rise or lower the bike? Anyone explain this? Finally, what size spring should I be using? 210lbs without gear.... I'm currently on a .95 spring
     
    Last edited: Aug 27, 2019
  2. pickled egg

    pickled egg Who lives in an air bubble under the sea?

    You need a thicker zip tie.
     
    Odilup, ToofPic, TLR67 and 5 others like this.
  3. MELK-MAN

    MELK-MAN The Dude abides...

    :crackup:
     
  4. Nytrozula

    Nytrozula Well-Known Member

    Thanks....that worked!
     
    Steeltoe likes this.
  5. MELK-MAN

    MELK-MAN The Dude abides...

    that was a good one... lol...

    i'd suggest more fork oil. try 5-10mm at a time. Oil level controls bottoming. your springs should be fine for some tracks, even being 210lb. may need heavier springs at other tracks, or as pace picks up, but you can still bottom without enough oil level even with heavier springs.
     
  6. Nytrozula

    Nytrozula Well-Known Member

    Thanks for the help.....of course I will be talking to the suspension guys at the track this weekend I was just hoping to get a better understanding of what is going on so i could try to talk somewhat intelligently and understand what my options are.
     
  7. Wheel Bearing

    Wheel Bearing Professional low sider

    Fork springs control where in the stroke the fork rides, fork oil control prevents bottoming out.
     
  8. stangmx13

    stangmx13 Well-Known Member

    u havent given enough info to provide good advice. which bike? what is the preload setting at now? are the forks stock?

    more preload raises that end of the bike. if you are just barely bottoming, a few more turns of preload will stop it from happening. If you are bottoming a lot, I wouldn't be surprised if your preload adjuster is at 0, which can be less than ideal on some forks.

    they both do both. they both contribute to the total springrate of the fork.
     
  9. TurboBlew

    TurboBlew Registers Abusers

    also you need your weight in gear... For me it was an extra 20 lbs
     
  10. kman0066

    kman0066 Well-Known Member

    If you have a go-pro (or similar camera) handy, it can really help to do a session aiming it at the forks. Watch for when it's bottoming out and let your tuner know. I just mounted mine right on the front/side of the fairing for a session. There's a difference between bottoming it out braking hard or mid-turn vs bottoming it out because you're hitting a large bump or two in just 1 turn. The zip-tie won't help tell you which is which. Heck, it could even be your rebound is too stiff and the forks aren't getting a chance to rebound before being compacted further on the next bump. Having the video can help show you what it's doing and aid you/your tuner in setting it up right. Raising the fork oil height (air spring) make it's stiffer as it goes, which is an exponential effect (increasingly stiffer the more it's compressed), thus resisting bottoming out and having a greater effect at the bottom and not so much up top, but assuming it's a typical weighted sport-bike, .95 for a 210 lb rider may be a bit light a spring anyways. I run .95 springs on my 675 and I'm 175 lbs. Changing the fork springs themselves has a more linear effect. They certainly help bottoming out, but they also have a closer to equal effect unloaded, mid-stroke, etc.

    Without a camera, I would first focus on getting the right springs (work with your suspension tuner), and then see how it's doing after that to see if fork-oil height changes are necessary.
     
  11. zippytech

    zippytech Running On Pumpedupness!!

    One thing to remember I don't know the skill level you are, but sometimes if you bottom out on the track, it maybe you are doing that part of the track wrong. Just a thought. I know I have learned sometimes I can find a smoother way and I will no longer bottom out.
     
    BigBird likes this.
  12. SPL170db

    SPL170db Trackday winner


    Add a few turns of preload, a couple mm's of fork oil and maybe a click or 2 on the compression damping adjuster. I'm 175 w/o gear and I run .975 springs, so you definitely need to jack that rate up a bit to support the front end.
     
  13. KneeDragger_c69

    KneeDragger_c69 Well-Known Member

    Bottming out doens't always necessarily mean the issue is in the front end.
    It could just be ONE place on the track that'll make you bottom out and everywhere else you'll be fine.
    We have two tracks here in Canada that will do that with my bike and soem other riders.

    The idea with the cam will let you know if that is an issue... or maybe you know of a hard hitting corner enterance.

    Cheers
     
  14. turner38

    turner38 Well-Known Member

    .95s are too soft for your weight IMO. You may be able to get by with them with more preload depending on your pace and how smooth you are. If it were me a I would put 1.05s in it for that weight and a 180mm oil level with 10mm of preload, assuming you are on a typical bike/fork...
     
  15. Nytrozula

    Nytrozula Well-Known Member

    I run an 08 R6 with ohlins forks up front and TTX in the back. I just checked the preload and it is 5 clicks from the end. I bought the bike last year when i started this sport and had the suspension setup then but I was never asked what my pace was when he set it up so never knew it was important. I now run a middle to slower advanced pace. I dont' seem to be having any issues with the suspension but was only concerned with the zip tie always at the bottom and that in time I would eventually have an issue if it was not addressed.
     
  16. stangmx13

    stangmx13 Well-Known Member

    theres the info we need.

    yes, I think your springs are too light for your bike, pace, and weight. you should pay a tuner and get the right stuff put in.
     
  17. mastermind

    mastermind Well-Known Member

    There’s this guy.... Thermosman. Go find him and all will be right.
     

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