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Open Source Downhill Project

Discussion in 'Downhill & Freeride' started by TrueScotsman, Jan 9, 2012.

  1. TrueScotsman

    TrueScotsman Monkey

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    I have been thinking a lot lately about an idea I have had that could revolutionise the way DH bikes are designed and made. Open Source Hardware and Crowdsourcing are meaning that instead of large Corporations telling us what to ride, we could turn the tables and ride what WE want.

    What I am suggesting is that a dedicated group of people like ourselves pool our talents and design, build and ride our own DH chassis. The basic structure of which would be open to anyone (even existing frame/component manufacturers) to customize or refine as they wish and produce their own compatible variations. Kinda like Linux for bikes.

    We have enough Designers, Engineers, Machinists, etc, etc, on this forum to do this- It would mean coming up with a frame/chassis platform and “bitesizing” it into manageable chunks. People could contribute to the project as much as they could manage, and everyone would benefit from an open design that anyone would be free to use/build/adapt.

    Don’t think it can be done? Check out Local Motors and www.lamoto2.es for inspiration.

    My thoughts about how a “platform” frame configuration could work go something like this; There is a “Core” (either actual or purely dimensional) that separate sub-assemblies fit around. You want a bombproof 4130 steel headtube assembly?-Fine. What about a carbon fibre seat tower? - No problem. A gearbox?-Sweet!

    img023.jpg

    This "Core" would have fixed dimensions (available to anyone) that would allow you to mix-and-match different sub-assemblies. These could also be upgraded individually as they broke or fatigued, or as you could afford. No more scrapping of an entire frame due to a cracked headtube- just buy a new sub assembly. Lighter, custom parts could be offered, such as a fixed-height non-adjustable seatpost sub assembly for weight-weenie racers. The swingarm would be a high pivot with idler/jackshaft- negating the effects of different drivetrain options.

    So, what about it? Open Source Downhill Project -Who's in?
     
    #1 -   Jan 9, 2012

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  2. Sandwich

    Sandwich Pig my fish!
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    I think that's a great idea, but it'll never take off beyond a small-builder circle. I love the idea of being able to swap front ends should you prefer carbon over alloy, or slack vs. steep, or whatever. I think the problem that you'll run into is that people love their suspension designs...whatever patented set of links and people cream over it. I think it would be a mighty challenge to make something that could accomodate both a high and low pivot, a gearbox and normal drivetrain, a rising rate and straight rate linkage, etc....but I like it.

    I also think you'd end up ruining the original concept, which is what looks like happened to the rally fighter. Last time I checked in, it was going to be a manual BMW diesel pushing upwards of 30mpg with AWD and street/off road air suspension. Now it looks like they ditched all of that in favor of a big V8 and automatic transmission...in other words, it's now an F150 prerunner that looks like a car.

    I wouldn't want to invest considerable time and effort into a design to have it bastardized because one thing or another didn't work out.
     
    #2 -   Jan 9, 2012
  3. Pslide

    Pslide Turbo Monkey

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    I also like the idea - very futuristic. I'm not sure people will embrace the concept, but I love innovative thinking.

    The problem I see is that when you design for so many options, you will undoubtedly make some compromises. And when your competition, let's say a V10c or a Session 10, is absolutely not making any compromises, then you've got an slightly less competitive product.

    Sandwich has it right thinking it would be hard to accommodate all the different variations. I for one, would not be so keen on the idler / high pivot setup, so I'm not really interested in a core that would accommodate one.

    What would be interesting is if you pooled the talent here, decided on a bike design that everyone agrees with, and then divvy up the design and manufacturing tasks to those who have the resources, spreading the cost. If we all worked off a common solid model, then everything should come together properly in the end.

    Of course, design by committee rarely works out well in the end...

    But I like your thinking - keep it up!
     
    #3 -   Jan 9, 2012
  4. Sandwich

    Sandwich Pig my fish!
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    You might be able to make multiple attachment points for the swingarm, so you could do low/high pivot, but then you'd have to adjust the shock mount too, which would be a bigger problem. You would probably have to decide on a single rear suspension setup, like a mid-high pivot, and then just go with it and let the dice fall as they may. That would allow more fun with the other frame bits.

    It's not entirely unlike the Gboxx concept, but the problem with that system, I think, was that it severely limited frame design and suspension implementation. You were locked into one set of cranks and one pivot point, and that was it.
     
    #4 -   Jan 9, 2012
  5. TrueScotsman

    TrueScotsman Monkey

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    Please don't take my sketch/doodle as an exact proposal. It was just merely an example of how such a "platform" MAY work.

    You raise valid points regarding such a platform limiting designs.

    Anyone else have any thoughts on how such an idea may/may not work?
     
    #5 -   Jan 9, 2012
  6. IH8Rice

    IH8Rice I'm Mr. Negative! I Fail!

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    DW, joeg and Bradflynn are sending out their hit squad on you


    interesting idea tho
     
    #6 -   Jan 9, 2012
  7. marshalolson

    marshalolson Turbo Monkey

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    this is a great idea man.

    if you could design the core to accommodate both DH and longer travel trail bike builds, and then use an e-style front derailleur or some similar, that would give some even broader legs as well.

    currently lots of small builders do front triangles and then source ventana rear triangles. this could really up the game and offer a ton more options.

    i would vote parallel link, rather than high pivot, but maybe 2 different options would make sense. parallel link for trail bikes and some DH bike, and super high pivot with idler for dh sleds.

    with a parallel link bike you can then offer say 10 different link options that cator to different suspension designs and amounts of travel, rather than being locking into 1 option only.

    really a fantastic idea.
     
    #7 -   Jan 9, 2012
    Last edited: Jan 9, 2012
  8. c101aviojet

    c101aviojet Monkey

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    I like the idea of making a custom frame, but I doubt the "modular" approach is the most practical.
    The requirement that all parts can lock to a common "core" imposes serious restrictions on them - which means extra weight, less specialization, less possibilities, etc. In your drawing, for example, by joining all parts you'd have a typical bike and a spare core. I'd reduce the number of interchangeable parts to front triangle, swingarm and seat post at most.

    My suggestion would be to have users agree on a certain geo, and then design 2-3 different frames around it. I'd say a "traditional" frame aimed for pure performance, and another designed to run on gearboxes. Given the low numbers of frames to build, steel seems the logical choice, but perhaps a taiwanese factory is willing to make a 100-150 run at a decent price. There are a few "easy" customization options that can be implemented, such as a multiposition rear dropout, ~3º headangle adjustment, swing link, floating brake anchor points, etc. (which, unless really well done, will be a source of headaches though).

    In my case, I'd love to have a bike sharing a few things with this one that you rarely see in off-the-mill bikes, such as the gearbox, constant lenght chain, sealed transmission, symmetrical rear wheel, etc.

    Ok, enough rant for today, wish you best of luck with the project! :thumb:
     
    #8 -   Jan 9, 2012
    Last edited: Jan 9, 2012
  9. Pslide

    Pslide Turbo Monkey

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    Not sure this would work. You can't offer 10 different link options on a parallel link bike without offering 10 different link mounting point options. Which means your core and your swingarm would look like swiss cheese.

    In my opinion, I would go with a single pivot bike with a linkage driven shock. With a clever linkage design you might be able to offer multiple linkages to fine tune the leverage ratio without needing multiple mounting points. Think Transition TR450, Commencal Supreme.

    Of course not everyone loves single pivots, despite the number of championships that have been won on them recently.

    I guess we are now seeing how many different preferences we have in terms of design! Will be difficult to please everyone, eh? :)
     
    #9 -   Jan 9, 2012
    Last edited: Jan 9, 2012
  10. Sandwich

    Sandwich Pig my fish!
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    Another option may be to consider linking the suspension system to the "core" so that the entire platform is interchangeable...allowing people to buy a "core" from turner with a DW-link suspension, a "core" from trek with ABP and FF, or a "core" from zerode with the gearbox and everything right in there.

    Specs would have to be made for front section mounting points, seat mast mounting points, and a "core" geometry, so users could pick a front end with an expectation of accurate geometry....ie, manufacturers of cores should only control chainstay length, allowing BB height, HA, and top tube to be largely controlled via the front section.

    That would actually be a pretty neat idea, honestly, though I like the concept of open source core as well.
     
  11. marshalolson

    marshalolson Turbo Monkey

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    ^^^^ good point ^^^

    settle on ~8" travel, 9.5x3" shock, and be done with it.

    if there was ever desire to do an open source trail bike, it would be easy to offer a bike with ~6" travel, and uses either a 7.87x2.25 or 7.87x2 for 5.3" or something.
     
  12. Sandwich

    Sandwich Pig my fish!
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    well for the trail bike, you could keep the same front end and seat mast and just swap out the core with a shorter travel version. You could keep the specs on the front end and seat mast the same, or change them slightly so that a DH, 64* front turns into an AM, 66* front, or a trail, 67* front. All with a 1.5" headtube, of course.

    It would be even more forward thinking to be able to swap out the suspension and swingarm as one unit. In other words, the BB would stay the same. You could swap your DH core out for an AM or slopestyle core without removing cranks or drivetrain. Talk about multi-functionality. Get yourself a fork that can change travel from 8-6", and boom goes the dynamite.
     
  13. TrueScotsman

    TrueScotsman Monkey

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    That's kinda what I was also thinking. The "Core" doesn't have to an actual part- it could just be a set of specific dimensions that all "sub-assemblies" adhere to.

    To illustrate this I did another quick sketch (complete with Ribi-type fork) that shows how head/seat/suspension assemblies fit together at points A,B, and C. This still give the option for custom angles and sizes but within a framework.
    img024.jpg
     
  14. Pslide

    Pslide Turbo Monkey

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    I like this A,B,C concept better.

    I also like your one piece carbon fiber seat mast assembly. I've been thinking about that same idea for a long time. Light, clean, and could be designed to allow better control between your legs. Could get expensive in a crash though!
     
  15. Pslide

    Pslide Turbo Monkey

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    PS - Also digging your artwork. You should illustrate highly technical children's books!
     
  16. Rick205

    Rick205 Monkey

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    I am subscribed to this, if you need components cnc machining get in touch, i would love to help.

    Something i have pondered for a few years now is the possibility of making a durable, 'functional' dh frame at a very low price-point using sensible material choices (steel) and local manufacturing.
    Its been done before but usually with quirky geo / suspension (think mr big's urt), weight would of course be the issue here.

    This could give options to build a frame in a 'budget' manner by picking and choosing the material / construction of your frame around the 'core'.

    Rick
     
  17. TrueScotsman

    TrueScotsman Monkey

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    Cheers Rick, this is the kind of great skills that we as a collective group can boast of.
    Yup, it would be good to build something that could be built up in a "budget manner". A person could always upgrade as they could afford later.

    Who else has da skills?
     
    #17 -   Jan 9, 2012
    Last edited: Jan 9, 2012
  18. fluider

    fluider Monkey

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    I love the idea of a collective work on one project as it gives many options. In either way it can lead to a complete bike design ready to be crafted with details of higher quality and that in quite a short period of time (when compared to 3+ years I've spent on my project in my free time). And it would only be up to us what we use it for, be it conventional bike, core-platform design with its finesses, new gearbox, linkage fork.

    What might seem unachievable or achievable at hich cost to one designer can be solved by a group of them. Such a community can potentially have much more ideas and man-working-hours available than most of commercial companies which are tied to other things.

    I like to idea of a mainframe core where different gearboxes could be mounted to different positions and then remaining frame parts would attach. And those frame parts could be made of a material one would like.
     
    #18 -   Jan 10, 2012
    Last edited: Jan 10, 2012
  19. fluider

    fluider Monkey

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  20. Steve M

    Steve M Turbo Monkey

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    Sorry for not replying to your email Ian! I reckon this is a pretty rad idea overall. I think the first thing you need to establish though is exactly what you're trying to achieve with it. Is your main priority:
    1. Outright performance? Keeping in mind this usually requires low weight, and bolted joins aren't a great way to achieve this.
    2. Product price? Because this pretty much rules out gearboxes from the start.
    3. Adjustability/nerd factor? This one is pretty cool but it more than likely will compromise on weight at the very least.
    4. Something else altogether?

    I think the ABC concept is pretty neat and the hypothetical options with it are exciting, but the obvious reality is that you aren't going to be able to nail all of the above when compared to a high end off the shelf frame, particularly because weight is so critical, which as Sandwich pointed out, will mean it'll be somewhat restricted to a relatively small circle of designers/framebuilders. If you are looking for optimum performance alone, then I think you need to take the reins and remove a fair bit of the the adjustability/modular build, and farm out various parts of the job to whoever's capable. However if modularity is the point, you have to ask what goals you're ultimately going to satisfy with it - because if cheap production is a key factor, then carbon parts for example are going against the design intent.

    Personally I am of the opinion that the most fully integrated designs typically yield the best overall performance (weight, ride quality and reliability), so I'd suggest that the design intent either account for that, or shift focus towards something else.
     
  21. TrueScotsman

    TrueScotsman Monkey

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    Cheers Steve, thanks for the input.
    To answer some points (if we take the ABC concept for example);

    1.For optimum performance and low weight some sub-assemblies could be integrated. This is the beauty of only specifying points of connection. You could, for example, do an integrated front head assembly and seat assembly, utilising only points B and C and ignoring A.
    How the points that ARE used are connected would obviously take some working out.

    2. As for cost, this is the beauty of the system. Each assembly could start out with a budget version (steel, standard drivetrain, standard seat assembly) that could then be upgraded to a premium version. This would hopefully help get more people into the sport. Hell, you could even do a BMX-inspired cheaper single-speed version!

    Keep the comments/thoughts coming........

    EDIT- for point 1 see illustration (obviously this has the benefit of lower weight but with the disadvantage of less adjustability)
    ABC2.JPG
     
    #21 -   Jan 10, 2012
    Last edited: Jan 10, 2012
  22. Udi

    Udi RM Chief Ornithologist: “I Brake for Birds”

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    Totally off topic, but just want to say big props to your contributions to the industry Rick, I'm still rocking the original cups from when you very first made them... have bought my second set recently (fancy updated design) and most of my friends have purchased sets of them as well.

    Reasonable prices, good parts, and good service. Keep it up.
     
  23. captainspauldin

    captainspauldin intrigued by a pole

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    I like the idea of the latest draw-up.. would be cool if you could something similar to the shock/suspension cage on a sunday and have everything bolt up to that. keep all the suspension packaged in one neat spot.
     
  24. Pslide

    Pslide Turbo Monkey

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    Paging Mickey...
     
  25. LukeD

    LukeD Monkey

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    risse_lassen_08_1.jpg
    reminds me of this....
    please don't make it like that.
     
  26. Rick205

    Rick205 Monkey

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    Thanks Udi! - :thumb: It makes consuming most of a whole year of my life with headsets worthwhile. :eek:

    Were hopefully going to have a few more products available this year because of the support from customers from the headset line (A new-to-us matsuura twin pallet cnc was delivered 2 weeks ago) - Were about providing products that are functional and dont cost the earth, which is why i would be happy to help with this frame where possible.....

    Rick
     
  27. limitedslip

    limitedslip Monkey

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    I have to agree with this. You aren't going to be able to compete on cost with a frame divided up into four customizeable pieces, it doesn't matter what material they are made from. And you won't be able to compete on performance against the wide variety of awesome frames available today.

    Then you've got quality control problems, liability, customer service.

    If you want to do something like this, I think designing custom swing arms for existing popular frames would be a good way to go.
     
  28. ebarker9

    ebarker9 Monkey

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    This is a really interesting idea and I'd certainly be interested in playing a role in it (ME/CAD/whatever).

    I would definitely echo the statements of those above. The project would need a very clearly defined goal and one person who ultimately decides what direction to take. I bet that a lot of us have had the experience of too many opinions taking a project in too many different directions resulting in a giant clusterfvck (see "The Pentagon Wars"). So yeah, avoid that.
     
  29. klunky

    klunky Turbo Monkey

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    Who cares - I just want to see your finished gear box bike
     
  30. TrueScotsman

    TrueScotsman Monkey

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    This was why I was hesitant of including sketches, in case people thought I was promoting that exact design, not the intent behind it.
    What do others think? Could this idea work?
     
  31. TrueScotsman

    TrueScotsman Monkey

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    Yeah, that is a wee bit stillborn at the moment :-( It is one of the things that lead me to this way of thinking. Someone could easily "experiment" with different parts of a frame without having to do a total design. This could help further bike technology- i.e. build a front head sub-assembly with a Hossack-style fork/shock mounting on the downtube!
     
  32. LMC

    LMC Monkey

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    I think it can work, but i think aspects of the design need to be addressed one by one as i fear this thread could become bogged down with many different ideas.

    For example

    Phase 1 - should the frame be single pivot, single pivot with link, horst link?

    then after that is decided, move to phase 2. High pivot/low pivot/ability to switch between high and low? then on to geometry, travel etc..

    The way i would suggest to proceed would be to conduct a series of polls so people can both express preferences, provide feedback and vote.
     
    #32 -   Jan 10, 2012
    Last edited: Jan 10, 2012
  33. c101aviojet

    c101aviojet Monkey

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    For me, the point of a custom frame is being able to ride something you can't buy at the typical bike shop, either because it's crazy expensive, because it must be custom made for you or simply because it doesn't exist.

    As I see it, you can find relatively cheap racing frames out there; making one doesn't really offer anything new, and you simply can't get the figures of a pro frame (don't get me wrong - of course, it's ubercool to ride your homebuilt cheap frame).

    That's why I would aim at doing something different, and implement working design solutions that most brands won't bother/risk trying.

    To illustrate my point, imagine a DH/FR bike with gearbox and enclosed transmission. It wouldn't be the lightest or fastest of the bunch, but would be dead silent, avoid chain suck/skipping/premature wear, save $$$ in broken parts and workshop hours, wouldn't detune in months, and it would last years of abuse (if it's not made crazy light). And there's still room to add plenty of customization options (head angle, fork type, linkage, etc.).

    Of course, I might be the only one that sees things this way. :(
    If I'm able to get some free time, I'll try to model something to add to the brainstorming. :D
     
    #33 -   Jan 10, 2012
    Last edited: Jan 10, 2012
  34. TrueScotsman

    TrueScotsman Monkey

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    Yeah, let's not let the thread get bogged down with too many ideas.
    I think that the idea that Sandwich had has merit- the suspension (pivot/links/shock) is integrated with the "core". This would allow future adaptions to be offered with different platforms (even potentially by companies that own patented systems- i.e. DW-link, Split-pivot, VPP, Horst, etc)

    But the FIRST thing to decide on the the co-ordinates of the Core points (like points ABC in my diagram if it is acceptable to others). Other specific dimensions/pivot locations can come later. Obviously the Core has to be large enough to fit a standard shock in varying positions. I will get onto my CAD tomorrow to play about with specific shock orientations, etc.

    A poll is a good idea as long as people are making informed choices. Therfore I ask everyone- how do you see a "core" working?


    EDIT- c101aviojet makes a good point, let's aim for something that isn't being done in the mainstream. Let's push things forward!
     
    #34 -   Jan 10, 2012
    Last edited: Jan 10, 2012
  35. LMC

    LMC Monkey

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    I would actually have the core and headtube as one piece, then the seat tube, swing arm and bottom bracket arrangement bolted on.

    Geometry/frame size adjustment for the headtube could be done by bolting/pressing upper and lower headset cups into the frame. If the head tube axis is offset by 10mm in each cup they can be rotated round to give +-20mm top tube length. Also if the actual housing for the cup is identical at the top and bottom of the frame the cups could be designed in such a way that swapping the top and bottom cups would alter the head tube angle. I have had a few systems like this made before for frame designs that ended up incomplete.

    I think your first sketch shows an ideal layout for the core, a little like the GT Fury with a space in the downtube large enough to allow multiple pivot locations and shock positions.
     
    #35 -   Jan 10, 2012
    Last edited: Jan 10, 2012
  36. Steve M

    Steve M Turbo Monkey

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    I think the ABC concept is the way to go here. Sandwich as always makes some pretty good points, and I think that the Core (can we spell this Coar please, and adjust the BB spacing with Coar Shimz?) does need to allow for a variety of suspension designs, but unless you're going to go full retard with a lattice of five billion adjustment points, that basically means the Core actually needs to fully encapsulate the rear suspension as well.

    What I would suggest doing is taking a look at the most popular/common/best bikes on the market, measuring up where their suspension components sit and establishing in cartesian coordinates the effective perimeter for the Core and the suspension components, and placing the joints for points B and C just outside that perimeter. As in, look at how much room you'll need for say a Banshee Legend suspension layout, a Sunday, a 224, a Glory/Operator/Session/Demo/Zerode/Balfa/V10/Commencal/whatever, check a few gearbox bikes, then make sure the perimeter of the core lies outside ALL those areas when they're overlaid. I reckon it'll end up being surprisingly large, and chances are you'll want to trim it down resulting in cutting out a few potential layouts etc but that's life really.
     
  37. TrueScotsman

    TrueScotsman Monkey

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    Cheers Steve,
    I spent some time last night doing just that- playing about with different shock/pivot locations and you are right- it does end up being surprisingly large! I also input the mounting dimensions for a g-boxx/v-boxx and pinion gearboxes.

    I also think you are right with the idea of trimming it down (it can't be all things to all people, it just ends up being a mess).
    This is the 2D co-ordinates I came up with for the Core (utilising the BB as (0,0) and the bike facing right.)
    Point A- (150,340)
    Point B- (200,100)
    Point C- (0,200)

    These are all very rough at the moment- if anyone has a CAD program of any type I would be interested to see how they line up with their designs.

    BTW- Coar, ha ha ha!
     
  38. Steve M

    Steve M Turbo Monkey

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    Yeah I think the hardest thing really is fitting the shock in there. You can mount everything else wherever you like, but shocks have a pretty much fixed length, and to fit them in that small space (esp with a gearbox in there) means you're somewhat limited in terms of how you package things.

    Also I think Point C should probably be a bit higher. I presume you have a copy of Linkage? If so, check it out - 200mm above BB height is pretty low really, especially if you're going to take up half of that with a gearbox of some kind.
     
  39. TrueScotsman

    TrueScotsman Monkey

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    You're right, 200mm is quite low for gearbox (g-boxx/v-boxx) fittings and/or Orange-type single pivot systems. The Pinion fixings are nice and low, however.
    Changing point C also has an impact on the other points, so these co-ordinates might be better;

    A- (85,350)
    B- (190,165)
    C- (-35,265)

    I am still at the playing around at the moment though, I will look at the Linkage files and see what I think.

    EDIT- just had a wee play at lunchtime on Linkage and I think that the above co-ordinates should fit the following type designs;
    Banshee Legend MKII, Turner DHR (DW-link), Transition TR450, Iron Horse Sunday (using the point A also as a link pivot), Trek Session88, Superco Silencer, Evil Revolt, Canfield Jedi, Giant Glory, Zerode.
    As I said this was a quick check, nothing concrete!
     
    #39 -   Jan 12, 2012
    Last edited: Jan 12, 2012
  40. ianjenn

    ianjenn Turbo Monkey

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    WOW. Big variety there for sure. I can only offer Product Photos of the "CORE", "COAR" when it comes that far along. Very interesting for sure.