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Upside down forks.

Discussion in 'Bling and Appearance' started by Sleddog, Nov 8, 2007.

  1. The new bike im interested in, is the GSX650F sports bike has normal forks ,meaning there not upside down.
    But my cruiser has upside down forks and it's also a budget bike ,same price new.

    So what the go with upside down forks and normal forks ,is there any reason for it ,to be one way over the other?.

    Or is its just for looks?

    And isn't it better to have the chrome cylinder hidden up under the fairing on a sports bike ,so it doesnt get crap all over it or stone-rock damage .??
    I mean they cover the forks on dirt bikes with plastic, although that really in the dirt and bush.

    Cheers Sled. :?
  2. Up side down forks are a bit like rear wings on sports cars, they may make a small difference but its bugger all and probably only useful for those that use the upper 2% of the bikes potential.
  3. Unsprung weight?
  4. For the average Joe there is no difference.
    My new Bandit has regular forks with guards to deflect debris.

    Nont pass up a bike just because it has regular forks.
    You wont know the difference.

    The seals in upside down forks are always wet which is a plus, but if a bike is regularly ridden they will be wet regardless.
  5. Just get the one with normal forks, and turn them upside down. Best mod I ever made.
  6. :roll: :roll: :roll: :roll: Thanks mate.

    So how am I going to see the road with the tyre and wheel infront of me.
    :LOL: :LOL:
  7. That's YOUR problem. Stoppies have never been easier though!

    Seriously, it's an unsprung weight thing. Lighter unsprung bits allow the suspension to act mre quickly to follow bumps in the road etc. The difference is fairly minimal to an average rider, plenty of right-way-up forks will feel as good or better.
  8. I don't think unsprung weight is the issue. The weight is the same, be it USD or NWU.

    Try torsional stiffness instead. Did I say stiff? Phnarrr phnarrrr.
  9. Really? Sure the whole jobbie might be a similar weight, but the unsprung weight would have to be lower on inverteds? :?
  10. The theory is unsprung weight, stiction and stiffness.

    The truth is there are a lot of cheap USDs on the market and a lot of pretty good traditionals.

    also USD are harder (more expensive) to service.

    I'd steer away from them on anything other then sports bikes.
  11. Can you explain why the unsprung weight would be different between USD and RWU?

    I am specifically referring to street bikes and therefore street materials. Any fork of any design would benefit from lower weight. So, the question is, what aspect of a USD design makes it intrinsically lighter than RWU?


    Oh, BTW, the thing I said about torsional stiffness was correct too.
  12. The heavier end of the fork is attached to the clamp, not the wheel?
  13. USD forks gives the bike a better feel when going around corners but if u are using it for crusing, i wouldnt bother.
  14. USD forks have the charming design feature that, when the seals go, they dump all their oil on your discs :grin: .

    Seriously, it's a stiffness and unsprung weight thing. But I'd rather have a good set of traditionals in decent nick than a cheapo and knackered pair of USDs.
  15. And I would agree with you on that. :)

    If you were riding blindfolded you wouldn't be able to tell the difference. (Actually, if you were riding blindfolded you wouldn't...ahhh, farged it) ;-)


    Trevor G

    PS Nice pun...steer away from them... ;-)
  16. Unsprung weight is the point. Yep, the whole fork weighs the same, but with a traditional fork the 'fat bit' of the fork is below the springs of the fork, so it is 'unsprung'. When the bike hits a bump the wheel, tyre, brakes and bottom of the fork all have to move up and down, and more mass means more inertia means more reluctance to move. With an upside-down fork, the 'fat bit' is at the top, and is therefore 'sprung'. Only the wheel, tyre and brakes have to move up and down, kinda thing.

    As has been said, the difference is pretty negligible in terms of the whole picture - it's that few percent on the edge...
  17. OK ,just let me recap and make sure I understand it.

    So, for you average rider thats blind folded ,trying to see the road with a tyre and wheel infront of him ,won't know the difference .
    Cool thats me!.

    I get what you guys are saying and about the unsprung weight bit ,but the forks would only weight a few kg's ?.
    So not a great deal of difference in the long run.

    Cheers and beers. :grin:
  19. I'd have though it easier to eat on a bike with upside downies due to the more compliant ride!? :p