Introduction: Three Wheel Bike Car

Picture of Three Wheel Bike Car

No gas pump for this car!  A Three Wheel Bike Car, with panniers, a cargo platform, 16 speeds, and a canopy. This project allows for worthwhile grocery trips, pleasurable joy rides, drive-through coffee or bank drive-ups, and the ability to carry what you need, whether that be croquet mallets, warm clothing, a load of groceries, you name it.

Step 1: Get Inspired.

Picture of Get Inspired.

This was an idea bubbling at the back of this bike mechanic's head for several years.To be honest, a recumbent or sit-down design never had appeal for me unless the extra bulk of such a machine could earn its keep by carrying loads. The three wheel design differs from a "long bike" with two wheels, by proving to be awesome on snowy or muddy pavement; there's no fear of laying the bike down in inclement weather. Sketching, collecting cast-off parts, measuring bike path widths, assessing what needed carrying, these went into formulating a somewhat unique design. 30 years of professional wrenching experience made technical issues like drivetrain design and general bike part selection and set up easy.  Welding was required; my skills are rudimentary as to prettiness of the welds. This partly owing to using a basic flux-cored electric welder. But destructive testing showed that the joints have integrity. Mechanical ethics of good joint preparation and careful fabrication essential. Accuracy in measuring and cutting, and so on. The final step of painting the frame is waiting until I'm sure I don't have any more last minute add-ons to weld.  I've been riding the machine since January.

Step 2: Assess Your Needs

Picture of 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.

Step 3: Gather Parts Before Making a Hasty Start

Picture of Gather Parts Before Making a Hasty Start

It is great to use parts you already have on hand. This will influence your design.  Which direction you go with a particular design decision is very dependant on the unique measurements of the parts you will actually use. So spend time accumulating ideal parts before cutting too much in the way of tubing or more involved parts like fabricating steering knuckles or rear dropouts. For example, the spacing on various rear hubs varies. You need to build the rear triangle to suit the actual wheel you will be using. A hefty frame like this can be very hard to cold-set to correct an error in rear triangle spacing.

I built all three wheels before almost anything. Having them is critical to laying out the frame. Brakes and other small parts were on hand early too, to help with the design process, and to be sure what I wanted was available.

Step 4: Take the Plunge

Picture of Take the Plunge

 Ideally, draw with a magic marker on plywood or even the slab of your garage, use a framing square to make a baseline and a centerline for reference. This will keep your frame from being cockeyed.  Work over this centerline during the frame build phase until the basic triangle is tacked together. To start, once you have general dimensions, lay out uncut tubing on the floor of your workspace, study the tube intersections and devise the best method  for cutting and fitting them together.  This could be hacksawing and filing mitered tube ends, or jigging up a properly sized metal holesaw in a drill press for clean "fishmouthed" miters. (I use a "Joint Jigger" fixture made for this purpose.)  Make good tight fits before entertaining weld-up. Think about any mods you want to make, any places where room will be tight, and get clear about any concerns with your build up. Are you a size 14 shoe?  Adjust frame to suit.

Some things to watch for: Make front cross bar that connects to the steering knuckles wider than the cargo deck, keep in mind that you don't want the turning front  wheels to hit any part of the frame in use.  However you will be limiting the throw with the steering components, and have some adjustability here. I used 26" wheels. If you use a smaller size wheel,  you can widen the frame triangle with more room before hitting the tire. But I prefer the better gear development and the suspension feature of a larger wheel. Too small of a rear wheel can cause problems with finding short enough spokes to suit a large-flanged internal gear hub. I have the tools to thread and cut custom spokes, but its a hassle. I just don't prefer the smaller wheels in this case anyway. I wanted some ground clearance, ease of climbing aboard, and there are a great many tire choices with mountain bike tires as well. You have choices, think about them and adjust accordingly. 

Step 5: Fuss With Drivetrain

Picture of Fuss With Drivetrain

I built a crank mast that allows for sliding the assembly fore and aft for leg length issues.  I prefer to keep the seat near the rear tire, for good braking and traction reasons. The bike car is great on those points, by the way.  The tube section added on top makes place for a derailleur as well as a bottle cage. 

Although large-loop chain tensioners exist that release and take up a great deal of slack, I'm using a simple short tensioner back near the jackshaft. This takes up slack when I go from large to small front chainring. I welded up a mount point onto the large jackshaft bearing mount. Seems to work well, although it won't take up enough slack to allow me to alter the crank mast position without also changing the physical length of the chain. I don't mind doing that, and I rarely need to alter the cockpit for anyone else. It seems quieter and less draggy than the larger units. and I'm running less chain with saves weight.  (But with this bike car, unlike my racing bikes, it has not been an obsessive goal to be nuts about weight.) 

I'm using a fixed cog on the 5/8" keyed jackshaft to drive the chain from the rear 8 speed internal hub. Then a freewheel cog from the jackshaft to the chainwheels.  I can play with the sizes of these to fine tune the gear output.

Step 6: Some Brake Opinions

Picture of Some Brake Opinions

For brakes, at least in the context of a bike car,  I highly recommend going with disc brakes, even though they can be fussy to align against occasional rubbing. The reason I chose them, besides their stopping power, is that I think a caliper brake is too limiting: for one thing, they limit use of really fat tires. They are flexy. Even with the better cantilevers, you are still subject to building a set of stays or fork-like frame supports to be able to reach the rim. With rim brakes, you are more affected when a wheel goes out of true, unlike with the disc brake set up. And with the wheelchair hubs, a great feature is to have nothing in the way of wheel repair maneuvers, especially flat repairs. The whole tire is removable without removing the wheel. Not so if you are building around cantilevers or caliper brakes. This is all especially true of the front steering wheels on this bike car. In the back, I do have a bolt on wheel that must be removed for flat fixing, but for me that's not a big deal, and is hard to avoid with a rear triangle. The 8 speed Sturmey Archer hub can be ordered as a disc brake model. Not worrying during a ride about rear wheel truing is a plus. I'm not advocating letting your wheels get out of true. But at least in the middle of a ride you're not subjected to a "show-stopper."

Step 7: Steering Issues

Picture of Steering Issues

The steering design is "underseat steering," a term you'll hear a lot in reference to trikes. I like a cleaner cockpit without a bulky steering setup over my lap. (this latter often is called "OSS" for short, meaning "overseat steering.")

Something different that I did: I engineered a system of cables to pull on the steering arms, with a T bar up front as a pulling point.  Being a section of headset bearing, it is smooth and has decent leverage.  It keeps steering hardware clear of the cargo deck. My main concern was to be able to tidy up the hardware that runs from the front to the underseat steering bar.  Many setups use a one-sided bell crank that runs off to one side, this can be a space problem depending on cockpit design. For me it would have crowded the pedaling leg space. My arrangement hides the pulling device (the cables) underneath the center fore and aft tube.  Clean, quiet, light, effective.  I needed to make custom brass pulley towers to reverse the cable action, as well as give them a narrow line up. Works pretty well.
In much shorter trikes, often the steering is direct, with the rider pulling on handles rising out of the steering knuckles. This wouldn't work on a long-wheelbase trike, too far to reach. Those steering handles can crowd the cockpit sometimes, anyway. 

 I used established principles for laying out the angle of the steering arms on the knuckles. (See sketch about Center Point steering.) You can research Ackermann steering for more about all this. Basically it's best practice to have the steering arms pulling on the steering knuckles in a controlled way that helps keep the inner wheel in a turn from fighting the outer wheel so much.  There still is some disparity owing to the tighter circle the inbound wheel cuts compared to the greater distance the outer wheel has to cover in executing the same turn event. But the way that the steering arm points to the rear of the "car" is germane. 

Other parameters, like caster and camber, deserve some study on your part, if only to enrich your knowledge base. For a slow-speed vehicle, there are differing opinions. Some say too much emphasis is given to the need for these angular dimensions to wheel mountings when you're not talking about a motorized vehicle.  Camber, especially if set to splay the bottom of the wheels out, can enhance stability in cornering. But it enforces a weird tire wear pattern, not landing on the centermost and thickest part of a cycle tire. It loads the spokes laterally. If a frame design is pretty narrow (and therefore more tippy left to right) a bit of camber can make some sense. Short, narrow sport trikes more often have camber.

Caster is a fore and aft angle, affecting the "trail" of a wheel from its pivot point as it steers. In a two wheel bike, the head tube angle and the bend or rake in a fork combine to make "trail" that produces stable steering results if done right. It's very noticable if done wrong. A bike steers poorly "no hands" if this dimension is off. (note that steering also suffers during "no hands" if steering bearings are too tight.)  Some say caster is less important on a 3 wheeler, but sloppy steering connections or poor weight distribution can introduce chatter if trail is non-existent or backwards.  (Think shopping cart wheel, rabbiting wildly at high speed, or when you push the cart backwards. On a shopping cart there is a large amount of caster, plus sloppy axles.)

Anyway, after much study, I incorporated very mild caster, and used NO camber. For my wide front end, long wheelbase, and loaded cargo platform, much that I read said that this could be the way to go. Some folks are hung up on this as they see visible camber on most all sport trikes they encounter, and assume it is de rigeur.  But I try to keep my designs in context and don't just blindly follow similar bikes if they aren't truly parallel to what I'm building.  In practice handling is very good.

Step 8: Get Out and Ride!

Picture of Get Out and Ride!

This was a great project. I hope you get some ideas and enjoy crafting one of your own. Since I first rolled out on it, I continue to be amazed at the fun factor--still not waning--as well as the practical usefulness.  No longer am I stuck grabbing 2 or 3 items and then needing to take the car to finish regular grocery shopping. Able to haul items for friends, including those croquet mallets and a picnic for afternoons in the park. With lights, reflectors, and a flag, evening rides in the dark are fun and cars make room in a way they don't for my two wheelers. The canopy cuts the sun, and reduces the frontal wind chill nicely. It's a hoot!

  Here I'll toss in a bit of advice for would-be welders:  If you decide to tackle this kind of project as a lark, in most respects the worst thing that could happen would be something that didn't go down the road well---except please don't take on welding "as a lark."  It can be easier than you thought, at the same time more frustrating than you thought.  My main point here is to remind you to "be a pro" as far as safety.  Put a sign on every door entering your workspace: "WELDING, knock first." Don't weld in the open in your neighborhood with kids or passersby being exposed to the blinding arc. Ventilate; save your lungs and other organs from the fumes. Wear a good helmet--an automatic darkening one is convenient as all get-out and helps technique as well; you can improve initial landing on the work with these helmets.  Learn how to run your particular machine.  Some are "hot" as soon as you plug them in, or as soon as you turn them on--this contrasts with others that will not let arc current flow until you actually press the trigger on the MIG gun. Every time you pick up the gun have helmet on and a clear path to the work.  It is good practice to have a safe place to hang the gun for when you stop-- assume it's "hot" and don't lay it on the floor or just anywhere between beads, that way you'll never generate an accidental arc. Learn to turn off the switch between beads as a matter of course. (you'd be surprised how easy it is to switch the amperage setting, when you meant instead to switch the box off.) This way if you borrow or use someone else's machine you won't get a nasty surprise from an "always hot" version.  Get some good books and search the 'net for welding videos. Others are more expert than me. I just want to pass on some good general shop ethics.


reighmey15 (author)2012-08-04

would it be possible to build this out of pvc pipe?

estructor (author)reighmey152012-08-06

It would be nice to think you could forego welding to build this bike car. However the main concern would be having enough strength at critical points if using PVC.
1. This frame is long by trike standards. In carbon steel, it has a degree of flex as built. This is desireable for comfort reasons. The length allows for more cargo capacity as well. If you just copied the frame in PVC it would certainly flex too much. In steel, the degree of flex is within what I expect it can tolerate for many cycles of use. This allowed me to have a fairly spare and uncluttered frame.
2. The use of quality bike industry parts creates the need to accomodate their inherent design requirements:
-Robust dropouts or other fixtures to firmly secure wheels. (Bolt-on axles, or quick release axles, would crush plastic fittings.)
-Firm places to accurately bolt on disc brake calipers; they have very narrow tolerances and will certainly rub if not precisely mounted. (rubbing is an issue even as delivered on industry bicycles.)
The are other considerations, but I'm not saying they aren't solvable...
I would guess that a PVC frame would need to be designed differently from the ground up. Instead of a few long frame tubes, I picture a truss-type frame for rigidity. Think of a box beam made up of triangulated angles meeting each other to effectively resist bending forces. This will be bulky; room for the rider and for key components will need careful planning.
In one iteration I would consider large-diameter tubing for rigidity. Go big. It does create bulk and space considerations but careful design might overcome that. I'd use 4" in early drawings. If that wasn't going well on paper, such as when trying to accomodate tolerances for the bike components, then revert to many small tubes in a truss frame. (I think this second idea more likely to succeed but no guarantee.) This takes more careful layout, more joints to prepare and construct. The weight would be similar, you'd need more tubes and more joints if using small diameter. Try building up a 7' length in whatever design you conceive, then place it over two supports. Sit on the beam. Is it flexing too much? This is not a very rigorous test but will reveal the obvious "fails" in early experiments. If it bends so much your bottom drags the ground, you know it won't work. However less bending may still be too much for bike part tolerances.
A way to unite the PVC to metal dropouts for wheels would be needed, say by using 1/4" aluminum plate. The dissimilar materials of plastic-to-metal call for a large joint area, I wouldn't make the plates too small. It would be hard to keep joints from loosening unless a good overlap of plastic-to-aluminum was made. I'd think about slotted tubes epoxied to large tangs of metal extending well past the wheel attachment area. (Note that slots for axles cut into aluminum will be more vulnerable than same cut into steel.)
My front wheels are attached with one-sided wheelchair axles and sockets. This puts a lot of load on a single attachment point, but is met by the steel knuckles I made. I don't know how it would go using plastic. I picture the wheels flexing and angling inward at their tops if the left-to-right frame in front isn't made very stiff. And whatever plate is created to unite the PVC frame here to a front wheel would be tricky to keep bonded & rigid. It has to hold wheel for rolling action, and be robust enough for turning forces at the same time. Any flex would lead to rubbing and scraping between wheel and frame. PVC is not built to endure cycles of flex. It has the job of resisting internal pressures on pipe walls, and in house plumbing it must be supported at intervals. So it lacks many qualities that efficient frame-building demands.
I think long-term durability will be lacking using PVC. It may be in the "disposable" bike car category. But it could still be a fun project!

Ok, I tried to make a PVC frame with lots of trusses and gussets and whatever, I want everyone to know that it will not work!! It has way too much flex and it cannot hold weight in the first place, don't try it, just get a cheap stick welder and make the frame out of mild or black steel, that is what I recently used for my trike and it's a little heavy, but it is STRONG. The only possible way to do it would be to buy a ridiculous width of PVC pipe and make a fat, and unorganized frame. Vehicles need to be made from metal!

Would like to build one of these but don't want it to weigh 200 pounds

GeorgeS56 made it! (author)2015-09-20

Cool Im just finishing my prototype then looking to produce a no weld frame

estructor (author)GeorgeS562016-04-29

George, I'm sorry I never saw this message! Great to see the prototype. Curious about the no-weld frame system... That'd make such a bike accessible to more makers. Hope it works (worked?) out!

GeorgeS56 (author)estructor2016-08-18

Hi I gave up on the quad due to weight and complicated steering / drive issues . The basis of the design was to be able to lay out between the rails in a camper type situation , adding the strength to cope with the rear axles and steering forces priced me out . I am however now working on a front drive rear steer trike that should enable me to achieve the same goals , will keep updating

OogieMustBoogie made it! (author)2015-08-24

I (sort of) made it! With plenty of variation, not to mention it became a gigantic fish in the end

Very cool, OogieMustBoogie!!

OogieMustBoogie (author)2014-08-10

Hello estructor, love your project and the background. I am currently erecting a three-wheeled vehicle with two wheels in the front as well. My design is similar to yours, however mine will have a five-horse tecumseh petrol engine on the back, the steering will also be different, but I love the cable idea. I really studied your project and got lots of inspiration, thanks for that! I'm really early in the build process, but I hope to make an entire instructable. Thanks so much!

Thanks for the comments, glad you gleaned something from my project. I look forward to seeing your result! Will it be motor-plus-pedal, or motor only? Either way, have fun with it.

It will only be petrol powered with a centrifugal clutch so the engine doesn't stall when I come to a stop. The rear axle is the rear portion of an old kent bike I picked up at a yard sale for $10. I'll keep taking pics and creating the instructable. Thanks again!

TheEbonieJeneus (author)2014-07-29

also with the wheels complete inflated I have about 9 1/2" ground clearance from the base of the vehicle...

I emailed you so you can send the pdf of project.

Meanwhile, the ground clearance you mention is comparable to a mountain bike's, measured from the center of the bottom bracket (crank hangar) shell. An upright rider pedaling from a saddle located vertically (as in a conventional bike frame, actually between 73° to 75° from horizontal) above this spot would have ample foot clearance, with their heels pedaling level or even with toes pointed down. However, if you are going to be seated recumbent on this trike you'll almost certainly need to raise the crank hangar above your 9-1/2" baseline, or your heels will drag the ground. (This is what I referred to in my first reply.)
Anyway, you've probably thought of this. I hope you're having fun with the project!

TheEbonieJeneus (author)2014-07-29

Okay Estructor... I am putting together some plans to show you images of the electric recumbent that I have already started modifying... The frame will be rigid with no suspension anywhere but I am using a hub motor built into a 20" chopper wheel that's 4 1/2" wide... My frame from front to rear (hub to hub) is about 6ft long... And it is about 38" wide between the two front wheels... And the center tube going from front to back is about 2" in thickness... I have a PDF but it is unfinished... Could you email me here to further discuss it...?

TheEbonieJeneus (author)2014-07-27

I am in the process of building an electric hybrid of this bike with 20" wheels all the way around... Any advice...?

I don't know enough about your build to give too much advice at this stage, but two things come to mind regarding your 20" wheel design:

1. What kind of electric motor will you use ? If using a hub motor, lacing the large motor into the smaller 20" rim may require custom-cut spokes, or else a crossing pattern more hectic than desireable in order to fit shortest stock spoke lengths. I use a Hozan spoke threader to cut & thread spokes when I build tight configurations. But you can also buy completed 20" wheels already built up with an electric hub motor.
2b. Conversely, perhaps you are looking at some other kind of motor which could be mounted on the frame and drive a transfer gear? But hub motors do seem pretty ideal for bicycle wheels and come in kits with good controls, seem well-thought out.

2. My drivetrain design with the crankset centerline comfortably located just a bit above the elevation of the seat (6"?-I'd need to measure) means my heels drop below the frame a bit toward the ground as I pedal. I have good ground clearance using 26" diameter wheels. My shoe size is 40 euro, many riders probably have larger feet & therefore more heel drop. I've used crank arms ranging from 155mm (pretty short) to more typical 170mm length without issue. You'll want to mock up or at least draw and consider your pedal-to-ground clearance using the 20" wheels. I assumed that even though electric, you'll also have a pedal-powered drivetrain? ("hybrid.") I don't think having the pedals located too high above your hips is terribly comfortable, while pedaling too low below your hips, if in a recumbent position, I think is a weaker body position for forceful pedaling. So examine this part of your design. You can create a higher seat mounting platform, & then a correspondingly higher crank hangar/bottom bracket set up. Remember your concern is more than just the length of your cranks; your heels will drop lower than your actual pedal location in most recumbent arrangements I can imagine.
--if you wiil be using a derailleur in your drivetrain, also check its ground clearance, as most long-chain recumbents require a long cage derailleur.

husamwadi (author)2011-05-28

WOW this is amazing!!!

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!

estructor (author)husamwadi2011-05-30

Husumwadi, thanks for commenting.

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.

husamwadi (author)estructor2011-05-30

The problem with electric motors is that the battery weighs 50 tons or something rediculous :P. And for the added weight, the range of electric motor is crap (10-20 miles at most).

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:

andrew318 (author)husamwadi2014-07-07

they are a little pricey

estructor (author)husamwadi2011-05-31

Husamwadi, (sorry I spelled your name wrong last reply)
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.

husamwadi (author)estructor2011-05-31

Gas engines are still good, and they make kits specialized for bikes.

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 :)

estructor (author)husamwadi2011-05-31

Ah, husamwadi, I can see you might be a candidate for a land-speed record! I like the way you think.

andrew318 (author)2014-07-07

I do not get how you made the thing that lets the wheels turn can u possibly send me more pics

charlie_r (author)2013-07-19

What you are calling "center point steering" is a quick method to determine Ackermann angle of the steering links.

THIS is centerpoint steering:

Where the angle of the steering axis intersects with the contact patch of the tire.

Ackerman steering:

estructor (author)charlie_r2014-06-23

Thanks, charlie_r.

It is as as I said in the Instructable: "I used established principles for laying out the angle of the steering arms on the knuckles. (See sketch about Center Point steering.) You can research Ackermann steering for more about all this."

Hansj3 (author)2014-02-04

what you are describing is literally called bump steer. Some designs use dampners or tuned freq pendulums however increasing steering axis inclination by adjusting camber, caster, and to a lesser extent toe

I8mAll (author)2013-07-20

Nice, no better than that, lovely work.
One problem I have found with two wheel steering is that hitting a bump or object with one wheel causes a turning motion around its steering pivot which is transferred to the handlebars.
Recently I was shown an easy answer. Weld the pivot angled slightly outward so its axis points to where the tyre touches the ground. This negates any twisting force and even leans the wheel into the turn.
I admire your stylish work, drawings and directions.

billbillt (author)2013-07-14


2nup350 (author)2012-05-21

Another idea for attaching the front wheels is to use a pedal shaft to replace the axle, old style metal pedals used shafts that would work for this. I heated and bent a pair of three piece bottom bracket arms into a 90 to make my steering spindles and used the bb shell as the pivot point. tack welds keep the pedals from unscrewing.

abadfart (author)2012-01-29

very nice i have been trying to build a tadpole for a while now. i had a apprenticeship at a recumbent shop and just fell in love with them. just a few quick note a rear derailleur makes a great chain idler. your best bet for visibility is moving color at eye level so a taller flag mast is better.

abadfart (author)abadfart2012-01-29

also smaller wheels up front like thoughts frome a chileds bike will improve stability

PENNY1999 (author)2011-12-26

i believe this is called a motorized tricycle.

abadfart (author)PENNY19992012-01-29

i believe it needs a motor to be motorized

estructor (author)PENNY19992011-12-26

Hi Penny1999,
See my comment about my bike car being 100% human powered. (my reply to you was posted as a separate comment instead of as a reply.)

estructor (author)2011-12-26

Hi Penny1999,
Just to clarify, my three-wheel bikecar is 100% human pedal-power. There is no motor.
(I did once think of eventually adding an electric motor after recent knee surgery, but have since found I can get by without it.)
lf you look at other photos in the instructible you can see the pedals, cranks, chain, and transaxle. The bulky rear wheel hub is an internal-shifting 8-speed device by Sturmey Archer, allowing me to change gear ratios and make my pedaling effort match the terrain or desired speed. But all motion is produced by muscle power.

The only external power on board is a small solar panel on the rear rack, that can recharge my 5v music device, or else charge AA batteries for my headlamps and taillight.

estructor (author)2011-08-06

Check out this instructable, might be helpful...
Good luck!

mxalive (author)2011-08-02

ivebeen trynna make a bmx bike with 2 wheels in the front and front suspension but i need to make a arms and idk how to make them do u have any ideas if so plz email me @

estructor (author)mxalive2011-08-06

Hi mxalive,
Sorry I didn't answer right away. I don't have any experience with fabricating a-arms... But someone here at the site submitted a project that had a front end idea that I think they took from the front end of a had suspension that I think might be what you have in mind. I'll search here and reply again with name of that project. One thing I would say, if it will be self propelled, you will want to think hard about how to keep the assembly light weight. Even car manufacturer's list the weight of a-arm suspension as a factor. If you plan to scavenge parts from heavier motorized units remember that the weight was acceptable for that use, and that suspension was designed for motorized speeds and kinetic behavior.
You don't have to think too hard about that, except to try and spec frame member material that isn't overbuilt for weight of a self-propelled contraption. Thinner wall tubing, lighter spring assembly, things like that. The weight of a motor is a significant part of load you are trying to damp and control. Otherwise rider weight is main load if framework is appropriately lightweight. I don't know if you are going self propelled.

In bicycle industry, and even on some light weight cargo trailers, elastomer 'springs' have been used, no hydraulic shock, with coil-over springs if travel (length of up and down movement) is noticeable--sometimes no coil spring if travel is short. But a-arm weight I think wouldn't be worth having if only used for short travel..not enough suspension benefit to pay its way?

estructor (author)mxalive2011-08-06

Hi mxalive,
Sorry I didn't answer right away. I don't have any experience with fabricating a-arms... But someone here at the site submitted a project that had a front end idea that I think they took from the front end of a had suspension that I think might be what you have in mind. I'll search here and reply again with name of that project. One thing I would say, if it will be self propelled, you will want to think hard about how to keep the assembly light weight. Even car manufacturer's list the weight of a-arm suspension as a factor. If you plan to scavenge parts from heavier motorized units remember that the weight was acceptable for that use, and that suspension was designed for motorized speeds and kinetic behavior.
You don't have to think too hard about that, except to try and spec frame member material that isn't overbuilt for weight of a self-propelled contraption. Thinner wall tubing, lighter spring assembly, things like that. The weight of a motor is a significant part of load you are trying to damp and control. Otherwise rider weight is main load if framework is appropriately lightweight. I don't know if you are going self propelled.

In bicycle industry, and even on some light weight cargo trailers, elastomer 'springs' have been used, no hydraulic shock, with coil-over springs if travel (length of up and down movement) is noticeable--sometimes no coil spring if travel is short. But a-arm weight I think wouldn't be worth having if only used for short travel..not enough suspension benefit to pay its way?

urov (author)2011-07-17

Hello, I would love to build one of these, but I am struggling to find a way to attach the front wheels to the frame as you did, could you maybe post pictures or some instructions as to how you did it?

That aside, FANTASTIC Job!!

How much is the overall weight of your Bike Car? :)

estructor (author)urov2011-07-17

urov, thanks for the comment.
Good question, the wheel attachment is something many folks wonder about. Lacking special wheelchair or cart hubs, many builders try to fashion a fork type arrangement so they can use ordinary front wheel hubs. I don't like the way that forces you to use a caliper brake, is flexy, and it also makes for slower flat fixes. (with open-wheel attachment such as on a wheelchair, you don't even have to remove the wheel in order to change a flat because no fork blade is in the way of pulling the tire off to the outside.)
The system I used was from a set of quick release wheelchair hubs. I actually modified a pair of front disc brake mountain bike hubs, by converting them to accept sealed bearing cartridges and the solid, side-attach wheelchair axles. I got lucky and the aluminum disc hub's machined recess that came with steel press-in cup races for ball bearings, happened to be the same press-fit dimension to accept the catridge bearings. This lets the heavy steel rods from the wheelchair hubs fit into the disc brake hubs, giving me a clean and powerful set up. I laced the hubs to mountain bike rims.
So the support for the hub is all on one side, with a release coupler that bolts onto the steering knuckle I fabricated. This coupler has a chrome release sleeve that can be moved to release the solid axle for wheel removal. It works similarly to a fitting on a compressed air hose for a nail gun or such, you push the outer knurled sleeve aside and a captured, spring loaded ring of ball bearings retracts, releasing the axle from the sleeve.
However, there are cart hubs that bolt on from one side, instead of being this fancy quick release method. That would be less expensive. I've had the wheelchair hub parts for 20 yrs or so and so can't give you current prices, but retail would have been over $100. If I hadn't had QR axles on hand I would have pressed in some cartridge bearings to a pair of front mtn bike disc brake hubs and then fitted a high strength bolt through the I.D. of the bearings. The largest I.D. possible, to allow a large diameter bolt. Getting bicycle industry hubs ideal so you can use bicycle brake parts. A pure hardware store cart hub or wheel could work but you wouldn't be able to mount disc brakes to that.

When I get a chance, I'll make a sketch of the hubs, axle, and steering knuckle design.
As for the weight of the bike car, too unwieldy to weigh on a bathroom scale, but I'm guessing around 65 to 70lbs total weight.

urov (author)estructor2011-07-18

I agree the wheel attachment has(d) me baffeled as well... I just couldnt figure out how I should go about it, so your explanation really helps! shame those hubs are that expensive ;(

As a regular mtb-er I do know that there are axles with 20mm diameters for mountainbikes, there also are 14mm ones. I may look into those a little more to find out if I can modify them, or simply use a wheelchair axle IF they are the same diameter... I can already see, this Project is not something to start without proper research, and preparation.

Thank you for your thorough answer!!

urov (author)urov2011-07-17

I also just noticed, I think heavy riders should be concerned about the front axle bending, as it only is attached to one side. What is your experience?

estructor (author)urov2011-07-17

Urov, the wheelchair axles tend to be solid and pretty hefty, with no threads to act as stress risers on the shaft. Very strong by design and in practice. And on a trike the weight is distributed more widely. For home made efforts using through bolts that are too light, that's a possible cause for concern. If you research specific wheelchair hubs there may be weight ratings. Just know that their design is meant to carry the weight on one side.

However, definitely stay away from trying to directly bolt one side of an ordinary front wheel's axle nut onto any kind of steering knuckle. That set up is not right for a cantilevered attachment. What I discussed was modifying a front hub by removing it's factory axle, pressing in cartridge bearings with a large enough I.D. to insert a continuous long through bolt, with a bolt head on the outboard side of hub, and the threaded end going to steering knuckle. With a lockwasher and a Nylock nut to secure it.

urov (author)estructor2011-07-18

OK, I must have missed the wheelchair hub part ;) now I know what I'll be looking for the next couple days Thx for the answer!!

SHIFT! (author)2011-05-09

Neat, a reverse tricycle for adults! Just curious, as a recumbent bicycle how does it factor in hill climbing?

estructor (author)SHIFT!2011-05-09

Shift, thanks for commenting. The climbing ability is better than I expected, of course this vehicle is much heavier than my various two wheel bikes. There's a hill a few miles from home that has been known to tempt me, when on my Vitus conventional racing bike with light Velocity wheels (bike total weight, approx. 19 lbs.,) to do some minor "weaving" at the steep upper portion. I'd say the top is over 10% grade. It's about 50 yards long, preceded by a longer grade below that takes moderate steady effort. The Vitus has a 39 tooth inner chainring, with a 23 tooth low cog on rear wheel. (700C wheels.)
I've tackled this hill on the bike car twice this spring. I'm able stay on board, and spin away to the top. It's a different mindset, for sure--more the tortoise, not the hare. But I wouldn't have done it the second time if it didn't feel "do-able." I just chug away and look at the scenery. I will say that if a buddy on a regular bike is along, you are of course outpaced, then you notice speed difference. On your own, with the ground very near as it flows by, the sensation isn't lacking momentum. All relative.
The bike car gears I have not done a roll-out on yet--I plan to put car in easiest gear, and see how far one pedal stroke takes it. Then put it in highest gear and do same. Because the Sturmey Archer hub has internal gearing I'd like to assess the gear development with this roll-out method. The chainwheels I'm using are a 46 tooth large with a 36 tooth inner chainwheel. I could put on a triple but prefer a cleaner narrower chainline if I don't need a 'granny' gear. (looks like I don't.) I have a 25 tooth 3/32" sprocket on the rear hub for the drive cog.
If anything I'm craving a bigger top gear. But at 18mph fully loaded on the flats, I wonder if I should just spin and keep the speed reasonable. At that speed I am close to 90 rpm pedal cadence if not over, "topping out" the gear.

As for reverse trike observstion, my rationale is that I am not in favor of a differential and a lot of extra drive hardware such as a pair of drive wheels would entail. Heavier, more maintenance likely, more to wear out, more drag, besides crowding the pilot if you plop them between a pair of wheels. (which I would do, to keep weight distribution over or near the drive wheels.)

Kaptain Kool (author)estructor2011-05-10

To make hills easier, you could attach a motor to your bike. Sweet bike though.

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