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Anti-Dive Brakes

Discussion in 'Technical and Troubleshooting Torque' started by jd, Oct 29, 2007.

  1. I know my bike's got them and the workshop manual does talk about how they prevent caster angle from changing during braking. What I don't get though is just how they do this, I know there's a few extra valves/tubes to the front brakes just curious to know how this has an affect on the front suspension compressing? :? .
    Also doesn't seem to be something still used on bikes which I guess raises the question of why not?

  2. #2 2wheelsagain, Oct 29, 2007
    Last edited by a moderator: Jul 13, 2015
    Found this; A control means is provided for restricting the flow of gas or damping liquid from the tubes to the chamber upon application of at least the front brake, the restriction of gas or damping liquid flow resulting in the telescopic compression of the tubes being restrained.

    From the sound of it there is a restricting valve in the fork that slows the movement of oil when the front brake is applied.

    EDIT: A-96WVILvY0[/media]] YOUTUBE video. I cant check it from work but could be interesting :wink:

    Hope it helps.
  3. Hmm so it would seem the brakes and forks are connected, that's the bit I wasn't too sure on. Makes sense though presumably wouldn't work too well on USD forks then. I guess this means hitting a pothole/bump under brakes could be interesting.
  4. Part of the reactive force in a conventional front disc braking set up goes directly into compressing the front shocks.

    You get much more dive for the same decelleration, when using the front brake versus the back brake.


    Have a look at that link, it might or might not cast some light on your specific question.
  5. Yep that article helps clear things up, thanks :). Couldn't see how it could eliminate dive but knowing that it only slows the rate of dive down makes it much easier to understand.
  6. :) My pleasure JD :)
  7. My experience of assorted old dogs from the early '80s heyday of the dead-end fad (factory turbos and 16" front wheels spring to mind) suggests that they don't :grin: .
  8. 2wheelsagain
    is right.

    Made very little difference to fork behaviour, especially when the forks were set up properly, but decreased braking efficiency so went out of fashion very quickly.
  9. yeah, the 1kf has anti-dive, i think it was only put there to make the fork removal/rebuild just a little more tedious. added an extra half a stubbie!
  10. I had a bike that had that set up, GPZ 900R, (if its the set up I'm thinking of) on one side one of the connecting tubes/hoses was blocked and on the other side all was working as it should. This made for a very interesting if not dangerous ride. I ended up getting it disabled altogether and the bike behaved much better.

  11. On anything m ore than 250 proddie weight (say 130kg) they are effectively useless, hence the reaon why the idea got dropped.

    Anyway, fork technology (such as updside downies, cartridge forks etc) has changed so much.

    Plus, true antidive has also proven ineffective due to the lucky side effect of shortening trail and thus improving turn in and weight over front wheel for braking.

    While traditional forks have their weaknesses, their side effects (while not initially planned) actually seem to be better than the alternatives at this point.
  12. I had these on my old XJ900 and they where a COMPLETE :!: waste of time. After countless attempts to stop them weeping, which would last for a short period, they still inevatibly ended up leaking again. Everyone I spoke to said they just blocked the hose to the proprting valve or removed them altogether and covered the spot with a blanking plate-which I ended up doing. Handled heaps better after that. :grin: