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Zedro, Noel, or any other frame-builder type..

608 views 8 replies 5 participants last post by  knollybikes.com 
#1 ·
I have started designing my first frame. I am currently an engineering student, but I am a computer hardware engineering student, bikes are a passion. I am working on a single pivot, yes I know the drawbacks, but I think it is a good choice for a first effort. Any advice on software for turning my paper designs into computer models? I would like to try some experimenting with pivot location to see if the forces would be chanelled where I want them. I have lots of crazy ideas, and I always think I should try to make the contraptions just to see if my ideas. This time I am gonna build it. Any advice is very appreciated.
Bobby
 
#2 ·
designers will usually use what they learnt on, or company has, so there are going to be favorites. I use CatiaV5, lots like Solidwork, theres Inventor etc. AutoCad is ok for the 2D work. I would see what package your school uses if they have any. You'll spend alot of time just learning to use the 3D programs, i would strongly suggest taking an intro course if you can.

BTW, starting with a single pivot is a good idea; people who generally dont understand the scope of the task always try crazy multiple bar systems 'just to be different' (and of course wont be followed through). Good luck!
 
#3 ·
Sounds cool!

I would definitely get familiar with a 3D solid modeling program. 2D programs like Autocad are fine for working out geometries, but even the sketch mode in most 3D modelers will be way more suited for what you want to do.

There is nothing wrong with a single pivot bike - What you need to do before you even think about designing is write down your goals for the bike. If you just start throwing pivots and swingarms into the modeler, you will most likely end up with something pretty un-impressive. I would REALLY rercomend that you figure out what you want your frame to do. NO ONE FRAME IS PERFECT. No one frame can be the best at everything. Even really, really expensive frames have comprimises somewhere in them. You can not have the best pedalling, best braking, most neutral, stiffest rear end, most plush, most low speed maneuverability, most durable and lightest frame on the market.

So, write down your primary goals: Do you want to keep the design simple, light, and easy to manufacturer? Then your single pivot will be an excellent choice. Do you want to make the bike neutral in braking bumps? Then you will need some type of rear floating brake (either a floating caliper or as part of a four bar suspension system).

Once you've got your goals, then go check out EVERY website that you can find to ensure that you're at least within the right area as far as geometry is concerned.

Now, you can begin to start the design process. If you're in school, you should use whatever 3D CAD software you can get access to for cheap/free. The two main programs that you'll find in the industry will be Solidworks and Pro-Engineer. Catia is very sophisticated, but prohibitively expensive if you have to buy it commercially - student packages are a entirely different story though :)

Also, keep in mind your manufacturing capabilities. If you're making these with your own money and labour, remember that any CNC maching that you require will be VERY expensive. You should be able to make most of your parts manually unless you have access to cheap/free CNC machining. Also, you'll want to find a good welder (preferably someone who actually welds bikes), and again, they will charge you an hourly rate which will not be cheap.

Finally, you'll need to find a heat treater (if you're making it out of aluminum) once it's welded. I would recomend that you use with 6061 Aluminum, or standard 4130 Cr-Mo. There is excellent availability of those materials, especially 6061 Al.

I hope that helps. Oh ya, find out as much as you can about suspension design, then do vector force diagrams (or do it in your solid modeler) to understand what impact your design decisions will have on your frame. Finally, don't build the first frame you design - you'll be suprized how many design changes you can come up with once you let your first revision sit for a few weeks.

Good luck and don't forget to show it off here once you're done!
 
#4 ·
Thanks!

Thanks to both of you, I have nothing but the utmost respect for both of you. I really appreciate your answers. Just a little background on my idea for a frame. I am looking to design a 6 inch travel, single pivot frame. I will be going for an elevated chainstay on the drive side and possibly a different shape on the non-drive. I want it to be burly enough that I can (free)ride it, and I will be building in aluminum, 6061 will probably be the alloy. I might try to design some sort of torque arm for the caliper, If I can't make my original idea for the caliper work. I guess I will be ordering Solidworks on monday. My mechanical engineering buddy doesn't even believe my obsession with bicycles. If Computer engineering doesn't turn out to be the major for me, I know I will enjoy mechanical. I would love to do what you are doing Noel, heck I would love to live where there are mountains, but I am going to be in FL until I finish school at least. Who knows maybe one day we can get a bunch of home-built MTBR freeride bikes together on the shore! Thanks again guys!
Bobby
 
#8 ·
mosplat said:
maybe not the industry (yet?)..

in the community on the other hand, is a totally different case.
heh, well i guess around here people know me.

Although i am thinking of another side project, have some ideas. This unemployed engineer thing is really starting to blow...
 
#9 ·
Zedro's place...

Well, his response is correct it's not the whole case...

Hey built himself his own DH mountain bike as a university project, which I'm sure provided a LOT of insight into suspension design, tolerancing, pivots design, etc...

So perhaps not working in the industry, but certainly experienced in the industry :)

Hey Zedro - send me an e-mail I have something that might interest you (not biking related)...
 
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