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Automotive Safety regulations for motorcycle frames

  1. Feb 17, 2012 #1
    Howdy folks

    Pardon any implicit or explicit stupidity in advance.

    I'm an EE major taking a class in Autodesk Inventor, and I'm probably going to do a motorcycle frame for a midterm project. While it will not be required, I'm curious to see if I can make something roadworthy. Does any government body and/or engineering association publish specifications for this particular thing? I found something by NHTSA about _imported_ motorcycles, but nothing yet about manufacture.

    Thanks much in advance

    << Personal information deleted by Moderators >>

    PS - what is the general take on Inventor? I have to say, after hating Autocad with the burning passion of a thousand suns I find it to be a very welcome alternative. I only wish it did thermodynamic simulations, but I guess that's what multiphysics is for.
    Last edited by a moderator: Feb 17, 2012
  2. jcsd
  3. Feb 17, 2012 #2


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    You should start Googling right now on motorcycle frames. Custom-builders like Jesse James can start from the ground up, but often buy pre-built motors and power-trains. There might be stricter regulations where you live, so don't generalize. Good luck, and have fun.
  4. Feb 17, 2012 #3
    Well, that's how I found the nhtsa stuff. But nothing looked useful yet.

    Gonna repost this in auto engineering, seems like a better fit.
  5. Feb 17, 2012 #4


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    Good luck! Remember to check engineering threads about rake/neck-angle, too. Some scary things can happen when you try to drive a bike that has been built to "look good"
  6. Feb 17, 2012 #5
    Wow - wikipedia has a practical use - shocking!




    Thanks for the rake angle tip - a big help! Still, would be nice to have something a bit more official. Surely enough rich lawyers buy bikes at this point that somebody may have demanded a formal spec by now?
  7. Feb 17, 2012 #6


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    You're welcome. A lot of backyard "customizers" have built tank-slappers that would kill all but the most experienced riders.
  8. Feb 17, 2012 #7
    As much as I used to say I hate it. AutoCAD is amazing. It just requires a different thought pattern to parametric modelling.

    The reason why you think it's no good is because you've never done a proper design scheme of a system yet. One day you'll be forced to use AutoCAD for 2d scheming, and you'll get what I mean.

    I have a pdf copy book somewhere on motorcycle dynamics.
    I'll have a look.

    You don't have to read it all, but it'll be a good reference.

    You'll never find a 'spec' for a bike, just like you won't have a spec for a custom built road car chassis.
    There will be minimum external regulations to meet, ie basic road worthiness. But that's the fun of design, there isn't a step by step manual.
    Last edited: Feb 17, 2012
  9. Feb 17, 2012 #8
    Googling "tank-slapper" yields... even more amazingly useful stuff! Thanks Turbo, you now have a new fan!
  10. Feb 17, 2012 #9


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    In the UK the the legal requirements are the "Road Vehicles (Construction and Use) regulations". Curiously there is a separate "construction and use" law for pedal cycles in the UK, but apparently no document specific to motorcycles. Try searching for laws related to road traffic in your country.

    However that may not help you much, because it will tell you what the regulations are and what test or inspection procedures are need to demonstrate compliance, but it won't tell you how to design something that meets the requirements. Actually that's how it should be - for example you demonstrate that a car design is crashworthy by doing a crash test, not be being forced to follow some prescribed design procedure which means you can't be innovative.
  11. Feb 17, 2012 #10


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    Thanks, again! I don't need a fan, but I'd love to save someone from a crash on a poorly-designed bike that only looks nice.
  12. Feb 17, 2012 #11
    Chris - just curious, what do you mean by system exactly?
  13. Feb 17, 2012 #12
    A collection of parts and assemblies, to achieve a specific goal.
    For example, a gearbox.

    There whole concept will be done in 2D first, a basic outline of all components, shaft centres, ideas etc. It's just so much easier to scheme in a drafting package like AutoCAD.

    So for example with chassis design, I wouldn't start it Inventor. I'd scheme in AutoCAD first.
    The idea of a chassis, is to just keep the cars components in the correct locations.

    So you can plot the pickup points on your suspension (for example) in AutoCAD. Then you can draw lines representing the chassis members. this will give you an idea of how long each member is before you ever start modelling.
  14. Feb 17, 2012 #13
  15. Feb 17, 2012 #14
    AutoCAD is still much, much better for a full system.

    I've moaned about AutoCAD on here, but it's only now that I don't have it at work any more. I know how much I miss having that tool
  16. Feb 18, 2012 #15
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