Step 2: Assess Your Needs
This instructable can't hope to completely walk you part by part through an involved project like this. If you've been around bikes in a more than casual way and have some fabrication chops, you stand to be ready to make something like this using your skills. Being the creative person that you are, you will also be poised to tweak and alter things to suit your needs. This series of sketches and photos of the bike car I built can serve as a good jumping off point for the bike car of your dreams. Myself, I don't like to build from point by point blueprints when I'm creating an original design. It's a process of designing and executing as you go. Feel free to borrow ideas from here.
Take stock of your physical dimensions in order to build a suitable frame. If you are over 180 lbs, you will likely need to incorporate beefier tubing than the 1" tubing I used, both round and square mild steel. Or you could add gussets, truss pieces, or use other ways to stiffen the longitudinal aspects of this rather long-wheelbase trike. Some flex feels good over bumps, that's a bonus of a long wheelbase. But undue deflection could lead to eventual failure for heavier riders. Think "custom" frame, and adjust to suit your build. As for length of the cockpit, it's good to have some room for adjustment. At a minimum, your feet need to clear the front cargo deck. If you are of moderate leg length leave extra room for that taller friend who will want to try your machine. You can have some flexibility by making the crank mast and the seat points moveable on their mounts in one way or another. Accomodating a rider with longer or shorter legs than yourself will entail changing the chain length with my current design. Incorporating additional chain tensioners can free you from that, but adds to cost of parts and adds a little bit of friction, noise, and weight to the drivetrain.
A basic starting point is to measure your sitting leg length: Sit with back against a wall with legs straight out, and measure the distance from the wall to your heels. This will define the general seat back-to-pedal parameter. Other things like height of canopy, width of steering bar, etc, you can work into the design to suit your build as you go. With this triangular frame design that narrows from front to back, be sure your heels will clear the side tubes as you pedal.
Take stock of your physical dimensions in order to build a suitable frame. If you are over 180 lbs, you will likely need to incorporate beefier tubing than the 1" tubing I used, both round and square mild steel. Or you could add gussets, truss pieces, or use other ways to stiffen the longitudinal aspects of this rather long-wheelbase trike. Some flex feels good over bumps, that's a bonus of a long wheelbase. But undue deflection could lead to eventual failure for heavier riders. Think "custom" frame, and adjust to suit your build. As for length of the cockpit, it's good to have some room for adjustment. At a minimum, your feet need to clear the front cargo deck. If you are of moderate leg length leave extra room for that taller friend who will want to try your machine. You can have some flexibility by making the crank mast and the seat points moveable on their mounts in one way or another. Accomodating a rider with longer or shorter legs than yourself will entail changing the chain length with my current design. Incorporating additional chain tensioners can free you from that, but adds to cost of parts and adds a little bit of friction, noise, and weight to the drivetrain.
A basic starting point is to measure your sitting leg length: Sit with back against a wall with legs straight out, and measure the distance from the wall to your heels. This will define the general seat back-to-pedal parameter. Other things like height of canopy, width of steering bar, etc, you can work into the design to suit your build as you go. With this triangular frame design that narrows from front to back, be sure your heels will clear the side tubes as you pedal.
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I really want one, and if you add an engine on the back, you have an easy dune buggy!
keep up the good work, and good luck for the competition!
It would certainly be possible to put a motor of some kind on this bike car.
I think I would favor a battery type, and probably would run it to drive the jackshaft with an accessory sprocket. I would try to locate related hardware away from the back wheel, maybe set up the battery at least under cargo platform that is made of expanded metal mesh. But as it is, I am enjoying the freedom of just pedal power. Electric motors, and especially batteries definitely add weight.
Now here is what I had set up on my bicycle a while ago and it may work for you. The problem was on my bicycle I couldn't really add a whole lot of weight so the battery was only 36 volt (2 miles range at max speed :( .)
try hub motors they work well:
http://www.electricrider.com/crystalyte/
You're right, the weight esp. of battery is considerable, and unless handicapped in some way, to my mind not worth it. Pedaling isn't that hard with this gear range. Might only gain speed--but for only a short range as you said. And then rider is stuck pedaling the weight of motor/battery home without assistance if battery dies. I am a fan already of hub motors. Good weight distribution, decent torque, etc. My desire to emphasize human power, and my specific desire to be able to use the lovely 8- speed internal hub in the rear drove my design in the direction I took. And I'm pretty happy with it.
If I was compelled to build same project with a motor, I would select a hub motor, with a freewheel on it or else a freewheel on the jackshaft. This would accommodate multiple speeds well enough. But I can't overstate the elegance and high function of the wide gear range Sturmey Archer internal 8 speed hub. Over 300% ratio. Better than most plain freewheel/chainwheel stock arrangements.
Aren't the many possibilities fun, anyway. Thanks for your comments.
I prefer gas powered bicycles because you can add a very hard to pedal gear, so that when you reach 35mph with the gas engine you can still get exercise from peddaling.
Thats what I would do :)
Couldn't you just add 6-8" to the frame rails where the seat is mounted, and make provisions for an adjustable seat? This seems to me to be a much simpler method of accomodating different sized riders than adding & removing chainlinks, etc.
For a faster top speed, you might consider a 2nd chain/gear set mounted 'reversed' to normal IE: The pedaled chain drives the small side of the set, then the larger side drives the final gear set (just something to mul over next winter).
I like your ideas, great I'ble! ;)
I'm slightly splitting hairs in the case of my bike car; it's not as if the handling becomes awful with these small changes, not at all. But as someone who has spent years riding, including more than a decade competitively, and who is interested in the handling subtleties, I've set this thing up with that in mind.
That said, there truly is the ability to just do the adjustments at the seat-end of things: but funnily enough, even that takes time, because you need to unclip the kayak seat, move it forward or aft, then slide the back pillar as well after loosening the clamp bolts. (not hard to do, but just saying, for comparison.)
The issue now becomes, are the steering bars still in a good position for the taller or shorter rider? They can live with it I'm sure, but it's true that the steering does not move with the seat, it is separate system of a bar and cables. (which would have to be lengthened or shortened if new rider was fussy.)
Meanwhile, for my purposes, there's nothing slow or hard about removing or adding links to the chain after quickly sliding the crank mast. Especially if "quick links" are used, such as made by SRAM or others. These have a keyhole fastening, for tool-less assembly/disassembly. This means you aren't having to drive out any chain pins which on most modern chains require the use of a special bullet-shaped leader to keep from gouging out the hardened side plates. These are consumable items, known as "hyperglide pins" in Shimano-speak. (some folks don't know you can't drive existing chain pins in and out willy-nilly anymore. The hardened side plates will shed fingernail-shaped crescents of metal, enlarging the holes and weakening the chain. The increased side-loading of modern shift patterns requires that chains be hardened, with robust pin design.)
About your high gear comment: I don't get a clear idea of your design, would love to see a diagram--even though my high gear needs will be easily served by changing chainwheel and/or rear sprockets.
Thanks again, stay tuned I'll be posting more pics of cable steer for someone who asked earlier.