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the gearbox thread

Discussion in 'Downhill & Freeride' started by xy9ine, Sep 17, 2004.

  1. xy9ine

    xy9ine Turbo Monkey

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    all gearboxes, all the time. is the derailleur doomed to extinction? planetary gears, ivt's & mystery boxes - are there designs that will eventually rise to the top & become standardized (read: affordable & commonplace), or will gearboxes always be limited to exotic applications? here's a forum for random discourse.
     

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  2. xy9ine

    xy9ine Turbo Monkey

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    here's a couple random pics to start: the b1 petespeed internal deraileur:

    gt's (nexus?) gearbox:

    nicolai's rohloff-based g-boxx:


    three interpretations. disuss.
     
  3. dw

    dw Wiffle Ball ninja

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  4. dw

    dw Wiffle Ball ninja

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    Not to derail your thread, but there are not too many engineers on this board, and as an aside, I dont think many of the engineers on this board have really thouroughly researched the application and its idiosyncrasies that surround each system. I think at this point, I am the only person in the world who has actually attempted to build any sort of gearbox standard and then successfully implement it on more than one bike. (The conglomeration between myself and Karl Nicolai of last year that brought forth G-Boxx)

    What im saying is that you are probably not likely to come up with much more than random people saying "thats cool". Nothing wrong with that, just saying I dont think that your questions can be accurately answered on this forum.

    Not to mention this has been discussed to all holy hell on this very site. Id suggest you start with the search feature.

    dw
     
  5. xy9ine

    xy9ine Turbo Monkey

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    true. i think an all-encompasing forum for armchair speculation & the latest developments might be a good thing. there can never be enough redundant debate & morbid horse flogging!
     
  6. dw

    dw Wiffle Ball ninja

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    ahahah :D

    flog on good soldiers!
     
  7. Wingnut

    Wingnut Turbo Monkey

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    Sorry, I'm Canadian ..sorry...
    I like the PeteSpeed design. Honda's is definately over-engeneered in my opinion, it's basically a four cylinder engine powered by the riders legs, but why turn perfectly good rotation into linear motion and back to rotation, is it only to acheive the near-infinate gear ratio's? Is the GT's similar to the Rohloff?

    I think the derailleur will stick around for a long, long time.
     
  8. Wingnut

    Wingnut Turbo Monkey

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    Sorry, I'm Canadian ..sorry...
    :thumb:
     
  9. EVRAC

    EVRAC Monkey

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    I'm a gearbox freak. I basically can't get excited about any '05 bikes, cause they all still have rear d's.

    Let's start a list:

    Honda
    GT
    Nicolai
    Evil
    B1
    Lahar
    BCD

    Anyone else?
    I heard rumors about a Rocky Mountain version. No pics or anything. A friend saw some drawings. Keep your fingers crossed.
    The more players in this game, the better.

    Steve
     
  10. xy9ine

    xy9ine Turbo Monkey

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    yay. a kindred soul. hey - you live down the street! cheers! does rm have an adequately sophisticated r&d dept. to develop something like a gearbox??
     
  11. ÆX

    ÆX Turbo Monkey

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  12. xy9ine

    xy9ine Turbo Monkey

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    damn, you build some neat machines, bcd. is that second one rohloff-based?

    here's some vintage gearbox (circa 1997): paul brodie's 99'er:


    i raced with a guy who had one of these back in the day. pretty nuts for the time.
     
  13. ÆX

    ÆX Turbo Monkey

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    paul actually called me one day to " pick my brain"!

    i had alway looked up to his bikes, then he called me.

    it was cool. :)
     
  14. xy9ine

    xy9ine Turbo Monkey

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    paul is a cool guy. he's now restoring/remanufacturing vintage road race motorcycles. apparently his work is highly regarded in those circles.
     
  15. buildyourown

    buildyourown Turbo Monkey

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    bcd,
    I notice your version with the der simply mounted inboard uses the same sliding sprocket that we saw in those eurobike pics. How did you accomplish this? Just wondering what you ended up using for a bearing. Considering the current offerings of hubs, I think this would be the best design. Good protection for the der but you still have parts that are easy to find should something break. Me likes!
     
  16. ÆX

    ÆX Turbo Monkey

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    well no, mine was fixxed to the bb and had chain line problems.
    this design also asi have said b/f makes the bike shift reeeeally slow.
    no quick shift b/c the ring at the crank is small.

    not the best design.

    i think a variable trans ratio is the best. one at the bb and one at the high pivot. they would work in congunction and cuthte space needed for ratios on half.

    i have been doing some drawlings on mine.
     
  17. Toshi

    Toshi Harbinger of Doom

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    gearboxes are pretty cool in my book
     
  18. ioscope

    ioscope Turbo Monkey

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    Planetary gears are complicated, use a triangle
     
  19. EVRAC

    EVRAC Monkey

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    Probably not.

    Alex, thanks for those pics. Nice to have a closer look. I read on your site that you're waiting for a Rolhoff 7spd. I wrote to Rolhoff about this, suggesting they make a dh version (for normal bikes). I figured a 7 speed would be lighter and a through axle would be sweet. They said no. The axle is the main part of their design, and it would cost too much to change. Other than that, why don't you like the 14? Seems to me more speeds = better. The Nicolai TST is a dh bike with 14 speeds. Sweet.
     
  20. EVRAC

    EVRAC Monkey

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    Bring back the Vite!
     
  21. CTR

    CTR Chimp

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    BCD, love the old school double barrel cranks there.
     
  22. ÆX

    ÆX Turbo Monkey

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    i talked to rohlof and there unit runs a high low two speed with the 7s to make 14. the bikes i design are for racing, where max amout of gears you need IMO is 7. i have a 4speed i am going to use at mammoth. i like not to have to DB click my shifter up and down to get gears.

    yes, it is true it would be too much to change there axle. it has to remain fixed and the gears drive off it. they could make a 7s only to be frame mounted. it would be narrrower and have no spoke flanges. they told me it could be done but i think the Gbox thing moved them in a different direction.

    the Vite will never make it off a LCD

    BCD, love the old school double barrel cranks there.

    man,! i wish carumba would have made it. i would still run them if they were a isis. a bike shop purchaced everything they ahde and were soposed to come back with a isis. never did though :dead:
     
  23. ioscope

    ioscope Turbo Monkey

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    squares wobble
     
  24. EVRAC

    EVRAC Monkey

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    How about using the new Nexus Inter-8 "Sport"?
    Got this info from the Shimano Europe site, search for nexus:

    Shimano SG-8R25 (NEW!)
    Internally Geared hub (Premium)

    Gear Change Support Mechanism

    Shimano’s gear change support mechanism uses pedaling power to aid down-shifting. The result is fast and accurate down-shifting with an exceptionnal light touch. Mechanical shifting resistance is notably reduced so shifting is not affected under high loads.

    Smooth Gear Change

    The smaller idling angle realizes shockless, smoother shifting for stressless comfortable shifting.

    Smoother Rotation

    Shimano’s precise manufacturing abilities construct an internal hub that rotates with significantly less drag than previous models.

    Close Ratio Wider Range

    The new Inter-8 hub has increased its gear ratio to 307%, compared to 244% of the current Inter- 7 hub. The new Inter-8 hub also incorporates a closer gear ratio allowing a more efficient and comfortable pedaling cadence. A truly “all conditions” internal hub has arrived.

    Better Sealing

    The new Inter-8 hub has adopted a labyrinth seal system that shuts out water, and dirt to extend the service life and maintain smooth in all environments. Optionally a waterproof dust cap can be installed on the non-drive side before shipment, in case you wish to use the hub for combination with separate brake systems as V-brakes.

    Robust Construction

    Durable planetary and step-up gear sets assure long trouble-free service.

    Premium Version

    Due to needle bearings and better internal mechanics even more durable.

    Speed 8 speed
    Silent Clutch Yes
    Shifting Power Modulator Yes
    Shifting Lever ST-8S20 / SB-8S20
    Corrosion Resist Coating Yes
    Gear Ratio Total 307%
    Gear Ratio 1 0.527
    Gear Ratio 2 0.644
    Gear Ratio 3 0.748
    Gear Ratio 4 0.851
    Gear Ratio 5 1
    Gear Ratio 6 1.223
    Gear Ratio 7 1.419
    Gear Ratio 8 1.615
    Axle length 184mm
    Over Lock-nut Dimension 132mm
    Spoke Hole 36H
    Spoke Size #13, #14
    Sprocket Teeth 16, 17, 18, 19, 20, 21, 22, 23T
    Weight 1550g
     
  25. EVRAC

    EVRAC Monkey

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  26. Tom DH

    Tom DH Monkey

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    I think gear boxes have got a future in MTB I don’t know if they will ever make it into the XC market but there is defiant potential for it in DH.

    The only problem I have with it is that it’s nothing new every one is just concentrating on using a rear gear hub and putting it into the frame. I am not saying that it’s a bad place for it to go but its just using an old idea.

    All the hype at the moment is about the gearbox but the so called gearbox is just a rear hub that has been in production for a long time. At work this week I was sorting out a room and I came across an old BSA bike. This bike just had something special about it and I couldn’t throw it away, so I thought I would tack it a part. It had a gear hub on it and I thought it was just a Sturmey archer one but it was a BSA now this hub had to be about 65 – 75 years old and was still going strong.
    Now my point is that this was an old hub, which uses the same technology as this “new” gearbox idea.

    What I am getting at is that we need to concentrate more on an actual gearbox not a rear hub and then work on the frame design.

    Then you have got the B1 that looks like just a cassette above the BB so not much going on there.

    Then you have got the Honda, which I don’t know anything about, but it’s the one that I think has had some thought about completely designing gearbox.

    It’s a good thing that all these companies are getting involved with this idea but I think that Honda are going the right way about it.

    And then you have got the compatibility problem, which I think will always be a problem. The g-box idea is good to try and make a standard but if gearboxes are going to be used then they are going to have to be part of the frames structure. So I don’t think that a standard could ever be made that all companies could use. They should concentrate on there own designs and the one with the best will make the most money.

    Having said all this I am very exited about this and the next DH frame I get I want it to have some sort of gearbox .
     
  27. EVRAC

    EVRAC Monkey

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  28. atrokz

    atrokz Turbo Monkey

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    it's the future no doubt. But is it the future for stock brokers and CFO's only? thats the bottom line to me.
     
  29. Toshi

    Toshi Harbinger of Doom

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    whoa. i haven't seen the insides of a honda gearbox of course, but i haven't heard anything to indicate it uses a funky ratcheting system like that
     
  30. ioscope

    ioscope Turbo Monkey

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    MBA says it's a crankset attached to a tranny-ish gear which clicks an adjustable angle rockerarm which ratchets another wheel which is directly attaached to a chain whick goes to a patented freewheel which can roll backwards, something about protecting the gearbox.
     
  31. trialsmasta

    trialsmasta Monkey

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    Is there somone out there working on an IVT?
     
  32. ÆX

    ÆX Turbo Monkey

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  33. prophet6

    prophet6 Chimp

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    bcd:

    Vintage!

    I could however see a hydrolic version of that... use something like a gripshift w/ a master cylinder to push hydrolic fluid. That'd run down a line and drive the spanners on those wheels either in or out.

    pretty neat.



    p6
     
  34. Kntr

    Kntr Turbo Monkey

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    The new Nicolai seems to be one of the best set-ups I've seen. I need a new trail bike in the 6" range and it looks promising but I still have to see the price.:(
     
  35. EVRAC

    EVRAC Monkey

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    mmmmmmm
     
  36. BMXman

    BMXman I wish I was Canadian

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    uh...Dave how about you rename that frame 2005;)...I need one now. I was really hoping to own both a HT and trailbike that were G-boxx driven but now my dreams have been crushed by the mighty dollar:(....D
     
  37. xy9ine

    xy9ine Turbo Monkey

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    may as well tack this link on here - some neat detailed drawings of the honda gearbox (the patent application): cvt
     
  38. xy9ine

    xy9ine Turbo Monkey

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    hmmmmmm... dw mentioned he had been exploring alternative gearbox applications. i suppose it could be something other than the (rohloff-based) g-boxx. (though it could just as likely be a hoax to throw e-speculators into a frenzy).
     
  39. ioscope

    ioscope Turbo Monkey

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    Has anyone actually torn off a derailleur, or broken one?
    I know it can happen, but I have only barely bent one, and it still works.
     
  40. Curb Hucker

    Curb Hucker I am an idiot

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