Quantcast

dw, gear box?

Discussion in 'Downhill & Freeride' started by dhkid, Sep 14, 2005.

  1. dhkid

    dhkid Turbo Monkey

    Rep/Likes:
    6 / 0
    Joined:
    Mar 10, 2005
    Messages:
    3,359
    Location:
    Malaysia
    i was just going throught a interview of dw on descent world, and came across this:
    :sneaky:
    where it came from
    so, anyone know what happened to that? dave?
     

    Please register to disable this ad.

  2. zedro

    zedro Turbo Monkey

    Rep/Likes:
    4 / 0
    Joined:
    Sep 14, 2001
    Messages:
    4,160
    Location:
    at the end of the longest line
    yeah common, tell us your super-secret prototypes and send me all your Solidworks models......
     
  3. escapeartist

    escapeartist Turbo Monkey

    Rep/Likes:
    4 / 0
    Joined:
    Mar 21, 2004
    Messages:
    1,764
    Location:
    W-S. NC
    He had a street proto with a gearbox and replaceable chainstayes at interbike a coupla years ago. I think it was the 2013 or something like that, signifying the year he though a gearbox might actually be available. I appologize if any of thats wrong, im trying to remember it off the top of my head.
     
  4. xy9ine

    xy9ine Turbo Monkey

    Rep/Likes:
    4 / 127
    Joined:
    Mar 22, 2004
    Messages:
    2,719
    Location:
    vancouver eastside
    that was the rohloff based g-boxx evil. dave mentioned something somewhere to the effect he was abandoning that kernel & exploring a completely different approach...
     
  5. zedro

    zedro Turbo Monkey

    Rep/Likes:
    4 / 0
    Joined:
    Sep 14, 2001
    Messages:
    4,160
    Location:
    at the end of the longest line
    that was the G-Boxx (modified Rohloff shared with Nicolai), but apparently he dropped out of that design project awhile ago
     
  6. dhkid

    dhkid Turbo Monkey

    Rep/Likes:
    6 / 0
    Joined:
    Mar 10, 2005
    Messages:
    3,359
    Location:
    Malaysia
    dave, where are you??
     
  7. dw

    dw Wiffle Ball ninja

    Rep/Likes:
    6 / 0
    Joined:
    Sep 10, 2001
    Messages:
    2,944
    Location:
    MV
    I've been working on some new and very different things in my spare time, testing components of the mechanism and applying for patents. I am not rushing it, The ideas are protected now, so I am just working on doing it right.

    I am no longer working on the G-BOXX system actively, from a structural standpoint and manufacturing standpoint I learned what I needed from the development and implementation.

    There are a couple of new and interesting gearbox developments coming from all kinds of places. It will be a cool couple of years. I still don't see gearboxes replacing conventional drivetrains anytime soon.

    Thanks guys!

    dw
     
  8. boozy1976

    boozy1976 Monkey

    Rep/Likes:
    5 / 0
    Joined:
    Sep 7, 2005
    Messages:
    129
    Location:
    world-euro-ger-bavaria-munich

    thanks dw you said a lot but nothing :sneaky:
     
  9. LOOnatic

    LOOnatic Turbo Monkey

    Rep/Likes:
    4 / 2
    Joined:
    Jun 7, 2002
    Messages:
    2,516
    Location:
    Hucking Race lines at WindRock while i wait for jo
    I hear ya boozy but you can't exactly expect the guy to unveil his specifics of world domination ..........
     
  10. oly

    oly skin cooker for the hive

    Rep/Likes:
    5 / 0
    Joined:
    Dec 6, 2001
    Messages:
    5,121
    Location:
    Witness relocation housing
    Less than 2 weeks to go for all the real goodies to be shown...
     
  11. S.K.C.

    S.K.C. Turbo Monkey

    Rep/Likes:
    4 / 10
    Joined:
    Feb 28, 2005
    Messages:
    4,097
    Location:
    Pa. / North Jersey
    hmmmmm...

    dw speaks with much secrecy...

    That means he's probably gonna drop something HUGE if it's ready in time for Interbike...

    Can't wait to check it out. If it is gonna look and work as cool as I think it is (it's from dw after all) I've got a plasma cutter on standby to retro-fit it to my Demo 8... :D
     
  12. Vrock

    Vrock Linkage Design Blog

    Rep/Likes:
    12 / 24
    Joined:
    Aug 13, 2005
    Messages:
    251
    Location:
    Spain
    Will it be a Monopivot??? or a DW-link with a Gearboxx???
     
  13. zedro

    zedro Turbo Monkey

    Rep/Likes:
    4 / 0
    Joined:
    Sep 14, 2001
    Messages:
    4,160
    Location:
    at the end of the longest line
    gearboxes dont solve suspension issues, just make it easier to design around a specific cog pair instead of a cog range. Question is, could you fit a DW-Link around a fat tranny.
     
  14. dropmachine

    dropmachine Turbo Monkey

    Rep/Likes:
    7 / 10
    Joined:
    Sep 7, 2001
    Messages:
    2,923
    Location:
    Your face.
     
  15. escapeartist

    escapeartist Turbo Monkey

    Rep/Likes:
    4 / 0
    Joined:
    Mar 21, 2004
    Messages:
    1,764
    Location:
    W-S. NC
    I really think this is the kind of attitude that will crack the whole conventional drivetrain replacement problem.

    E-speculation at its E-finest.
     
  16. dhkid

    dhkid Turbo Monkey

    Rep/Likes:
    6 / 0
    Joined:
    Mar 10, 2005
    Messages:
    3,359
    Location:
    Malaysia
    eh... no teaser? :mumble:














    edit: :p
     
  17. Rik

    Rik Turbo Monkey

    Rep/Likes:
    5 / 1
    Joined:
    Nov 6, 2001
    Messages:
    1,086
    Location:
    Sydney, Australia
    That sounds depraved :help:
     
  18. Vrock

    Vrock Linkage Design Blog

    Rep/Likes:
    12 / 24
    Joined:
    Aug 13, 2005
    Messages:
    251
    Location:
    Spain

    Yeah I know, DW bikes and FSR's........ brake better too, but all the Geaboxx bikes that I've seen are monopivot, sometimes with a linkage for the shock but I'll de cool to see it all in one bike.
     
  19. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    ^ hope this helps answer your question ^

    [Nicolai G-Boxx - OEM Binder]
    "First we must answer why they were developed in the first place. All these systems try to eliminate the adverse effects (bob) cause by the chain force vector. With a derailleur based transmission, the chain vector is different every time you make a gear change. For example, when the chain runs on the biggest sprocket of the crank arm and on the smallest cog of the rear wheel, the force vector has a positive angle (upward). On the opposite end, when the chain runs on the smallest sprocket of the crank and on the largest cog on the rear wheel, the force vector has a negative angle (downward). In both cases, this result in a movement of the rear swing arm associated with the bob sensation. The amplitude of this reaction will vary with the gear ratios you select but it will always be present. With the G-boxx you don’t have to worry about this anymore. Why? Because you have a completely neutral system as the angle of the chain vector is always the same (perpendicular to the wheel path arc), the chain running on two sprockets of the same size, one on the left side of the G-boxx (at the same position as the single main pivot is located) and the other on the left side of the rear hub. With this configuration no force momentum is induced in the swing arm by the pedal forces, so there is no up and down movement (bobbing). The chain line is entirely independent from the gear ratios selected in the planetary gear cartridge and the chain tension is also always the same because the rear swing arm rotates around the main pivot of the G-boxx. As no chain growth occurs you don’t need any chain tensioner of any sort. "

    With regards to braking forces, there are methods like floating brakes (which in essence, are much less complicated, lighter, and cheaper than multiple pivots) that help alleviate braking induced 'jack'(that word makes me laugh, because it's the total wrong word to use. Thanks RC :nope: ), or better termed, squat and stiffening. Even so, many riders don't feel the need for floating brakes on single pivot designs, as is evident on many pro rigs and the original application in MX. Plus, the benefits of the single pivot (minus the negatives via a gearbox) are worthwhile when utilizing a gearbox (stiffer, good rearward wheel paths, simpler, lighter, etc).

    Hope that helps answer your questions pertaining to why gearbox bikes are all using single pivots.
     
  20. dw

    dw Wiffle Ball ninja

    Rep/Likes:
    6 / 0
    Joined:
    Sep 10, 2001
    Messages:
    2,944
    Location:
    MV
    That is a very inaccurate representation of how and why suspensions work.
     
  21. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    So it's completly false or not entirely complete? Because it does have much truth to it, but I know it does not tell the whole story (pivot location, etc).
     
  22. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    Ooops, double post.
     
  23. dw

    dw Wiffle Ball ninja

    Rep/Likes:
    6 / 0
    Joined:
    Sep 10, 2001
    Messages:
    2,944
    Location:
    MV
    Both. Read up in the archives. Plenty of great info there.

    dw
     
  24. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    I've read up most of the suspension threads here, and it does not take away from what Karl says here. To say it's false is incorrect, as it has truth in certain suspension systems that locate the pivot in areas around the BB.

    Granted, your design is different, as is most others, but this helps to answer the question as to why most GB bikes use single pivots: there is no need for much more as most sytems (yours included) are created for BOTH braking AND pedaling. When your gearing is internal, and the system essentialy operates like a jackshaft (drive chain on the axis of pivot), why use a more complicated sytem as you dont need to correct the pedaling efficiency (bob, feedback, etc) anymore?
     
  25. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    Maybe you can help shed some light here (using only gearbox bikes as examples, as this is the topic at hand), if I'm missing the point....
     
  26. manhattanprjkt83

    manhattanprjkt83 Rusty Trombone

    Rep/Likes:
    17 / 261
    Joined:
    Jul 10, 2003
    Messages:
    8,795
    Location:
    Pittsburgh, PA
     
  27. Vrock

    Vrock Linkage Design Blog

    Rep/Likes:
    12 / 24
    Joined:
    Aug 13, 2005
    Messages:
    251
    Location:
    Spain


    I'm with DW in this one... This is Wrong: "With this configuration no force momentum is induced in the swing arm by the pedal forces, so there is no up and down movement (bobbing)."

    With a GearBoxx you still have bob but you can optimize the rear suspension for the main gear and that's good. With a Multipivot you can optimize the system even better but it only works "Perfect" in a gear, in the rest of the gears it have to much o too low Anti-squat.

    Floating brakes are a good solution but most of de Gearboxx bikes have a linkage for the shock so you have a lot of pivots too. Similar weight, similar maintenance and similar cost...

    I'ld like to see something like this...
     

    Attached Files:

  28. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    of course your with DW on this one.
     
  29. dw

    dw Wiffle Ball ninja

    Rep/Likes:
    6 / 0
    Joined:
    Sep 10, 2001
    Messages:
    2,944
    Location:
    MV
    This EXACT point has been discussed in detail on this board within the last 60 days. I'm sure you can find it.

    There is a lot more to controlling vehicle attitude under acceleration than putting a pivot concentric to a power output and calling it good. I am not the only person in the world who has recognized and written about this subject. You can purchase Tony Foale's book at www.tonyfoale.com and read what he has to say. Linkage systems have all of the advantages for a single sprocket as they do for a multi sprocket system. I don't expect you to take my word (or anyone elses) for it. The physics is proven in theory and in practice. Nothing can change that. When the time comes you can ride it and feel it for yourself.

    Something to consider further is that multi sprocket systems have advantages over single sprocket systems in some ways. Take for exacmple and XC bike that uses a granny gear climbing hills, and a big ring descending. dw-link takes advantage of this and shifts the anti squat curve to take advantage of gearing and attitude in relation to gravity. Without the multi chainring setup, there would be less than optimal anti squat when climbing. Of course, dw-link is very unique in this respect, I'd say the only system in the world taking advantage of this situation today.

    Ten years from now, when production motorcycles are using linkage suspensions, you can remember back to this now.
     
  30. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    What gets me, is that you quoted something that states nothing in reference to using either single pivots vs mutiple link systems and said it was wrong. It's not. It just states that with a gearbox, the effects of varing force vectors with have a varied effect on the suspensions reaction to pedaling input forces. Something thats completely ture.

    I'm the one who answered the question regarding single pivots, and I attached Karls quote (which was quoted"") so I'm the one you should have quoted and stated was incorrect no? I have that oppinion though, not for solely performance purpsoes, but rather for manufacturing simplicity, and product reliablility. And after seeing the pic posted above me, I have allot of questions for your design.

    With regards to that, I'm looking at that pic of the sunday with what seems to be a gearbox inside the lower linkage. How does that work out, and what materials are you using to keep the intergrity there. What range of gearing can you use and what material process is invloved with creating something like that? It's very interesting to the imagination.


    Edit: Just found out that one of the Monkeys created that pic, so scratch that out :o: .

    Also to add, I should point out, with regards to the G-Boxx quote, that there are differences in force input with Flats (pushing down) and Clips (spinning). i am aware though, that this is for DH applications as well, and that seated spinning is a rarity, so for that I maintain interest in DW's workings.
     
  31. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    You do realize, that if you go and re-read my post, you agreed with every thing I said then stated you were, in essesnce, 'against me'? :thumb:
     
  32. dw

    dw Wiffle Ball ninja

    Rep/Likes:
    6 / 0
    Joined:
    Sep 10, 2001
    Messages:
    2,944
    Location:
    MV
    For me, all I stated is that what was previously written is incorrect. The statement that you cut and pasted assumes that chain force is the only factor that contributes to "pedal bob" (or the lack of a sufficient amount of anti-squat to counteract mass transfer under acceleration). The fact is that chain force is ALWAYS the MINOR of the two internal forces in a chain driven suspension system that make up a squat amount. The major force is always driving force. You would have to have an infinitely small rear sprocket to have them be equal and that is not feasable as you can imagine.

    Hope this helps

    dw
     
  33. OGRipper

    OGRipper Turbo Monkey

    Rep/Likes:
    7 / 106
    Joined:
    Feb 3, 2004
    Messages:
    9,684
    Location:
    NORCAL is the hizzle

    I don't have a very sopisticated understanding of a lot of this stuff but I think you are ignoring acceleration, mass transfer, and other factors that have an impact on suspension performance. Chain forces are only one part of the equation, and the Nicolai language makes it sound like chain forces are all that matter. As you rightly point out, they don't even recognize that the pivot location needs to be optimized for the one gear. Sure with a gearbox you don't get varying vectors - which according to DW can sometimes be a good thing - but you still have all the other challenges.

    Edit: Whoohoo, sounds like I wasn't too far off!!
     
  34. dw

    dw Wiffle Ball ninja

    Rep/Likes:
    6 / 0
    Joined:
    Sep 10, 2001
    Messages:
    2,944
    Location:
    MV
    Matt you wil be designing bikes with Joe before you know it! That would be sweet.

    Dave
     
  35. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    So how then, do you intregrate the gearbox package into a DW link bike (which I'm from your post says is the only system out that takes this factor into consideration)? The whole point is eliminating the drive train not for effeciency issuse but rather for reliablility issues. no?

    With regards to the G-boxx quote, it is not the whole story(underline that part) behind the G-boxx, rather one reason why a gearboxx helps. I'm certain that if there is a way to intregrate a gearbox into a linkage system that even helps further, they will be looking at it. Also, keep in mind that may have been writen before DW had his working linkage out which is said to be the system that uses these forces.

    We need to divide the two perspectives. I said single pivot. The quote said why gearboxes eliminate chain induced bobing and feedback. Could be the translation as well, as I highly doubt Nicolai doesnt know about forces involved in suspension.
     
  36. OGRipper

    OGRipper Turbo Monkey

    Rep/Likes:
    7 / 106
    Joined:
    Feb 3, 2004
    Messages:
    9,684
    Location:
    NORCAL is the hizzle
    I don't know about that one way or another, but whoever wrote that excerpt glossed over a lot. For just one example, they claim there is no chain growth if you use a gearbox, which you know is not necessarily correct. At best it's just one more example of a disconnect between marketing and engineering, at worst it's intentionally misleading.

    And hells yeah Dave that would be pretty sweet!
     
  37. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    There is no chaingrowth on any of the G-Boxx bikes. That said, the writing was from an OEM binder.

    Edit: I should point out, that the M-Pire stiffens under acceleratron, which is accomplished by simple physics using trig and force vectors. So there is more than one way to skin and cat...
     
  38. OGRipper

    OGRipper Turbo Monkey

    Rep/Likes:
    7 / 106
    Joined:
    Feb 3, 2004
    Messages:
    9,684
    Location:
    NORCAL is the hizzle

    It is misleading to suggest that if you have a gearbox you have no chain growth, as if you can slap a gearbox on any frame and suddenly chain growth goes away. I think you know that it not true. If what you say is true it's not just because of the gear box, it's because of the gearbox and, more importantly, the frame configuration.
     
  39. atrokz

    atrokz Turbo Monkey

    Rep/Likes:
    12 / 79
    Joined:
    Mar 14, 2002
    Messages:
    1,556
    Location:
    teedotohdot
    Who is misleading who? This point was based on the G-boxx, which evidently enough, has no chaingrowth. You could be misleading readers by making the claim that I stated all configurations dont have growth.
     
  40. OGRipper

    OGRipper Turbo Monkey

    Rep/Likes:
    7 / 106
    Joined:
    Feb 3, 2004
    Messages:
    9,684
    Location:
    NORCAL is the hizzle
    Easy there. I said the Nicolai OEM booklet is misleading at worst, but more likely it's just optimistic marketing speak. I don't know you, but unless you wrote it, I didn't say you might be misleading anyone, so relax.

    And to say the G-boxx has no chain growth...um, ok, sure, but as soon as you put one on a frame with chain growth, you will have chain growth and need a tensioner of some kind. If all the G-boxx bikes pivot around the bb, have a pivot pulley, or have otherwise been configured for no chain growth, then yeah you can say all G-boxx bikes have no chain growth. They also might not have a desireable axle path or other suspension characteristics, but who cares about that as long as you can claim no chain growth right? :rolleyes: Like we've said from the beginning, it's only part of the equation.