AbiliTTV

First, this forum is amazing. I have gotten so much help and insight so far. Thank you.

I started out asking about a dual shifter control - one control to two derailleurs.

And, we have gone on to the frame and the fork placement, all in the same thread.

https://www.bikeforums.net/bicycle-me...onnection.html

The image here is the general direction I was going.

The frames and forks are from Walmart grade bikes. The central frame is a 2x2 inch square steel weight bench frame.

I have posted links to other images of a different fork arrangement.

Wondering what anyone here might think.
This is a handcycle meant for casual use. No extreme use. Mainly paved roads, and smooth pathways, maybe crossing some grass, and going over a curb.

The forks are not being used for any shock absorbing capabilities.

I want the steering to be as direct as possible to keep it as simple as possible.

I am working up another model using the more traditional fork placement.

Any tips, ideas and thoughts will be welcome. Play devils advocate for me. Your insight and experience outweighs my mechanical knowledge.

Andrew R Stewart 

Wow, all sorts of questions come into my mind.


Are the cranks actually positioned where effective hand cranking occurs? It looks like the cranks are very closest to where one's chest would be, I would have thought that a bit further forward a location allowing for fuller arm extension would make sense. It's hard to tell but it looks like the steering ("head tube" of sorts) is WAY laid back. As in well past chopper flop area. Maybe I'm not seeing another element in the steering. Why show suspension forks which weigh a lot more then ridged forks do if the suspension is not functioning? You say "I want the steering to be as direct as possible" yet show a steering angle and sloppy forks which are likely to hinder said directness, let alone suspension being "simple".


My small experience with challenged riders (and why would one limit the power available to the weaker arms if the legs were functioning?) is that a body position and the odd contact points must be heeded. So starting with the body's dimensional aspects is a good first step. Was this your approach?


I have to wonder how much of this project for the project's sake, opposed to actually ending up with a highly functioning hand powered "bike". Have you ridden currently available hand powered "bikes"? So much of your ideas and initial designs seem to suggest you haven't. Please fill us in on more of your process to get to where you are now. What are your experiences with the bikes you have used? Are there any other goals/need this machine needs to fill? Andy.

AbiliTTV

The forks position are based on the low recumbent handcycles I have seen online. However, these have a wider turn than I expected.

The seat will be able to slide into a position to allow my arms to reach the hand pegs as I call them, accounting for my body dimensions.

The only handcycle I tired was a trike in the style of grandpa and grandma 3 speed. As for any others I can not find a LBS that has other models for me to try.

The biggest goal is to build an affordable handcycle. The trike styles start about $1,500 to $2,000 for a three speed. When an able person trike runs about $500 or so. The road only handcycles start about $2,500. Off road options start at $3,000.

Hand cranks start about $1,000. Making it very costly to even enter hand cycling casually. The design I am trying to create is not meant to hurdle down mountains doing drop ins, and jumping stumps and logs. That looks amazing but, I am more looking to tackle some paved hills, maybe some grass as I roll over a field, smooth walking pathways more cruising riding.

For people with disabilities we do not have an entry level basic handcycle. With that in mind I am using garbage bikes from Walmart or some like store. Paying about $125 each.

Here are some new images of the latest thoughts on the design. I really wanted to keep center frame as level as possible, however this is a good compromise.

I do not yet have the bikes, I only get paid once a month on SSDI, and after all bills are paid I may be able to order the bikes. I wanted full suspension as it keeps the rear triangle smaller than a hard tail bike.

The images are not to scale.

Awesome questions and great points, and it is these things that are allowing me to make adjustments prior to the build.

The weight bench metal is 2x2 inches 16 guage I am pretty sure this will be strong enough for this use. If not I can strengthen it.

AbiliTTV

The images are squished up, and the frame has more room than it appears here. Sorry about that.

Andrew R Stewart 

That explains a lot... Thanks for not taking my questions as an attack or flame. They are meant to fan your flames of discoveries.


In my many years at the LBS I have sort of become the guy who deals with the weird stuff, recumbents, challenged riders set ups, tandems and frame repairs. I've had many of these types of discussions a number of times before, perhaps the earliest was the Alenex prototyping. I was lucky to work in the shop that did some of their "normal sort of" bike work and part supplying. I wish you the best at solving your challenges and ending up with a highly functional bike that isn't too pricy, A worthy goal. Andy.

AbiliTTV

Actually I really appreciate the time and questions you posed.

I started with the idea I could buy a ready made handcycle used for maybe $500 to $1,000 so far here I am.

It makes it crazy tough trying to decide to buy a handcycle untest driven. Then the annoyance of saving to get that one would take about 2 to 5 or more years. Seems to me a lot of time wasted if I end up disliking the ride.

You asked solid hard hitting questions. It does help knowing what goal a project has. Is it to just kill time, or is it be productive. Very reasonable to ask.


I used to be the neighborhood bike mechanic as a kid. And, was 25 years old when I last was able to ride a 2 wheeler. It's been canes, then crutches, a walker, donated wheelchairs, then my daily use TiLite ZRA with Spinergy Spox wheels since 2008. A guy needs another ride sometimes.

You actually helped much more than you know. I will keep this updated as the build gets underway.

If this works, crossing my fingers this build will cost using only off the shelf retail priced parts $450. IF I get media blasting and powder coating it goes up about $300 or about that. But, that will be later when I can afford that, and see that this works. Not to bad overall for a proof of concept.

Keep on being yourself I loved it. Thanks again.

AbiliTTV

This image is more to scale. Also shown is the rear framing for towing my manual wheelchair. Mounts will be built on the fly.

dsaul

That image, as drawn, will not be able to steer. By connecting the two forks rigidly to a single handlebar, you have effectively locked them in the straight forward position. A better solution would be to connect the handlebar to a central pivot on the tube that connects the two head tubes and use a linkage system to connect to steering arms on top of the forks.

Live Wire 

Have you looked at One-Off? it would depend on your own needs for body position of course, but I always thought their configuration makes the most sense. It lets you get "on top" of the pedals if you want...almost like the difference between sitting and standing on a regular bike. Plus it would be a lot lighter than the 4 wheel/2 drivetrain image above AND you can still make it mostly with donor bike parts.

AbiliTTV

Here is the steering system I am thinking of making. It appears to connect using pivot points. It may even use a bearing to make a smoother movement.

This mountain bike looks wicked cool by the way.

AbiliTTV

Yes, I have looked into One-Off and many others that use the forward facing position like that. Only for me it would not work out to well.

AbiliTTV

The images show raked forks being used, and levers for propulsion. While I am not using levers, my design puts the cranks and hand holds in about the same placement as they are. This placement is equally ergonomic if not more so than hands out front.

I am combining aspects of all of these to create a bike that works for my needs.

Recumbent is the most comfortable position for me. The next best placement for hand pedals if I can't lay facing down over them is put them in the same position while recumbent.

I want to put the hand pedals in a plcement that allows for a more ergonomic way of propulsion.

The Lasher Sport ATH-FS road bike orange raked forks has 29 inch wheels. That is my dream ride in a tadpole configuration. Image shown.

squirtdad

couple of observations.

Steering and braking is decoupled from propulsion by a lot of distance. this seem problematic and likely unsafe

why have the dual side cranks, derailers etc?

It would seem like the cranks will be out of sync always. this would seem to be a problem for efficient use From what i have seen (but have no experience with) hand cranked bikes are either set up like a standard crankset with the hand grips at 180 degrees from each other or the hand grips are side by side.

beyond that this approach is much more costly to build and maintain , 2 cranks, 2 Bottom brackets, 2 change 2 derailers, 2 wheels, etc. The complication of keeping gearing shifting reliably and equally on both sides will be a big maintenance issue

all of this extra complication is opposite of the goal to building a cheaper hand cycle.

overall the design as a whole does not look practical.

AbiliTTV

Separate controls of steering and braking/shifting and such has been done for years now. I am using the same distance between my hand points as on any of the Off Road rider facing towards the ground position.

Might want to take a look at those models,this link has a ton of system set up with both separate from each other. It is a google page with images of them: https://www.google.com/search?q=off+...w=1366&bih=672

The distance in my design is the same as on those. I just position myself so it works for me. It is about like driving a stick shift in a car. For the person new to it, having used auto only it appears unsafe and problematic. When it actually is very safe, and less trouble than the automatic version.

Costs - No matter if I design two front wheels one rear drive wheel, or one front drive wheel two wheels back or a four wheel design it all costs the about the In my case. I am trying to build using only new parts and source bikes. $360 to $450. OK, if I opt for two forks instead of a duplicate bike I might save $50. But, I may need the frame for my build, and I could buy steel tubes, and maybe save $50 dollars, when you consider shipping also on the separate parts. Where in ordering 2 bikes, and parts I get free shipping for all of it.

As for the maintenance no worries about that. I mean I keep my families bikes rolling. So what are in effect two more drive trains?

The biggest reason I shared was hoping that maybe someone had built a dual rear drive and or had a workaround for it. Seems that is not the case.

The design I show now is not to scale, and is not yet adjusted to fit a human rider. But, that is a matter of real world adjustments.

This is the paper napkin rough draft.

The front wheel is NOT a solid mount. I used one header tube and connected the rear triangle to header tube in a way that allows it to function as the front forks. It makes all the gearing and such much easier to manage.

One the crank you will see what appear to be a dozen or so other crank arms. That is only to determine the radius/diameter of the pedal motion.

The down tube will be placed in the same angle as the header tube in order to let the cranks rotate around the down tube as I pedal.

I will take the handle bars in this design and cut the ends off and fit them over the free spinning spindle of the pedals and screw it in place on each. Why not weld? So it makes it easier to adjust and replace down the road.

The seat will not have the down tube going through it.

I may still separate the brakes from the steering if the cables are at to steep of angles to not break while pedaling.

That oddball rear framing is for my wheelchair to hook it's front casters over so I can tow it behind me. I need a way to walk around when I get places in the bike.

The rear wheels are using the two front forks. Mind you they are not going to be used for the springs in them. The odd rectangle flat pieces represent weld points in the most crude fashion. They are connected at two points for added stiffness and to maintain the camber of the rear wheels.

Camber is where the tire touching the ground is spread out away from it's natural center if standing straight up. This allows for stability in turns and just overall.

My first choice a four wheel design. I just like the looks better. Second fave style is the 2 front wheels Tadpole design ( I will try to design one of those also). Last is the three wheel design two rear trike design. Just personal preference is all.

AbiliTTV

In the images above with the levers. Notice the yellow framed mono tube bike - It has ZERO brakes, gear shifters on the handles. They are located right under the left and right corners of the seat. Perfect example of a hand cycle using this design. It does not appear to use rear brakes also.

AbiliTTV

My last design is a tadpole style ride. The first chain would be a loop of I am thinking 10 to 13 feet or so. The possible placement to the other side with a cog connected to the crank hub could work also with slight adjustments to this design.

Handlebars connect as they do on the dual front wheel mountain bike in the posts several up from here now. The rear framing is again so I can bring my wheelchair places so I can walk around once I arrive. The placement of the cranks and handlebars are right above and below each other. So switching between the two will be no issue.

I could opt to put the shifters, brake levers and such on the crank handles as I did on the trike version above. However, I really do not see why considering I still need to steer with a separate handlebar.

Steering is done by pushing left to go right and right to go left as the leverage done this way works that way. It would take a few minutes to adjust to that. The pivots would use sealed bearing to keep movement smooth.

Just wanted to say to everyone - THANK YOU
You got me to realize my dual drive as I wanted it won't work. Well not like I was thinking.
That is huge. Being so close to the idea makes me blind to the issues it could have.

I went online looking for like ideas. I find many and some odd ones. None like this set up.

One of the best things with the 3D program is I can show that I am progressing or getting the ideas you share. and put them back out as I interpreted them. Make adjustments and when the build starts, actually build something that works.

I rather make a million model mock ups, to get it right, than one real world turd. Based on some silly idea I could keep the drive system in sync. No chance of that.

So thank you.

I hope my 3 wheel design are possible.

fietsbob

Now design the alignment jigs for the various parts you have to make, to have it come out straight.

David Tollefson

I'm not exactly sure how that steering system is supposed to work.

unterhausen

using forks at that angle is not going to be happy-making. That's why people go to car-style steering

Eta, the one handcycle you show with a fork at that angle has a hefty centering spring to counteract the massive wheel flop.

AbiliTTV

Did a lot of homework since my last update. Did not know about this ackermann steering, it really solves a lot of issues. It is more complex than the ideas I started with. But, hey it's my first time doing this. And, the best part I only enraged a few pixels in my 3D program, and not waste a bunch of good parts, and time well making a mess. I am sure it work as a doorstop.

As for the fork placement, I agree they look iffy at best. So thanks to everyone's posts, questions and such I kept going back to the starting point. Took some time. I found images of tadpoles I could make sense of. And, the best by far was finding free as in 100% free open source tadpole plans. And, reading about this ackermann steering system and kingpins... I thought kingpins were bad news. Turns out, they are very helpful for steering.

This configuration will allow me to turn and the front wheel will lean into the turn based on the direction I am going. The steering mechanics are way out of scale. I made them bigger and more beefy than they will need to be. But, I feel this design is the one I will build.

Images show lots more detail than I usually show. On the frame rail you see what appear to be rivets, these will be holes or stop points for the sliding seat, the sliding handcrank bar angle adjuster, and the seat back and pan positions. They will be smaller holes than these appear as to not ruin the strength of the frame.

The front V arms will be the down tubes off of the two bikes I will use. The handcrank will be the seat post welded to the cranks case, and the seat tube will come from an oldie but goody found bike that did not sell. So the height of the handcranks will be adjustable to different riders, or sear positions.

Using one steering rod keeps the front end less congested and easier to maintain overall.

You will notice the forks in an very goofy position. This is because I am not using disc brakes for this ride. I need a place to mount V brakes or caliper brakes. They also will serve as good spots to install lights, fenders and such. I personally do not mind the extra weight they add to the bike. I need the exorcise.

The chain drive system. Using a long front or first chain on the left side, so that the rear triangle will function as normal is easy to work on and such. Plus it seems to make sense to use both sides to avoid the steering mechanics and all.

I will see if using the rings the largest and middle might work as chain guides. To keep the chain from slapping and bouncing, I will use pivots on the two larger rings, and place small pulleys or cogs. I will add springs or something to the pivots to keep the chain tension throughout all handcrank adjustment points. Since this chain does not involve the rear derailleur I can keep it under a little more tension. Not to much as I don't want to break it, or stretch it out.

I added a chain guard, and the handles on the handcranks are on a swivel sleeve over the pedal spindle. These will remain in the same handing or where my hands like to angle them positions. Notice the design leaves the cables in a nice arch that won't fatigue them like my first design.

Also you see a second set of brake levers on the under seat steering. They are on a picot joint. I got thinking if I am steering and need to stop suddenly... Or if I am pedaling.... Why not a redundant brake system. So in an emergency I am not as likely to crash.

The shifting will be done only on the handcrank handles. As this makes the most sense since I must be moving to shift gears.

The design has come a long way I think to reach this point. Could not have done it without all of you. So thank you.

I will continue to add detail and modify what I can.

If anyone knows of simulation software of the open source or free type that would be awesome. I would like to test my steering design, the chain drive and maybe braking.

This is the combination of many images I have seen and also adaption from some plans for a tadpole recumbent that I got online for free and I am making this based on the parts I have and will have. It can be bolted together or welded.

dsaul

Are the steering and drive still separate? How do you plan to keep it going in the right direction while your hands are on the cranks?

AbiliTTV

Weight. Both the frame and my body weight will cause the wheels to self right.
The mechanics of this design are based on simplified car steering. If you ever noticed while turning you need to handle the wheel. As you straighten out, the vehicle remains in a straight tracking line without your hands on the wheel. It is based possibly on this or some variation of the Ackermann steering method.

I order to turn the handlebar will need a little force to move it, this is done using the kingpins as the balance point for the front steering.

While turning left or right the front wheels will also lean into the turn. This makes the frame also pivot on that lean. Since the frame weight, and my weight keep pushing down, as soon as I remove my hands from the handlebar the wheels will return the forward position as that is where everything is in balance. No need for springs, or dampers.

A multitude of high end off road handcycles employ dual controls, you should check youtube for off road handcycles. Pretty cool designs. They are meant for extreme or rugged use. Mine is meant more for a casual use based on how I must sit.


I am trying to locate software to simulate steering like this, and also bicycle chain motions. Opensource/Free would be best.


As for the keeping it the right direction - That will be pretty easy. Once I am moving, I can steer to where I want using the momentum to keep me moving.

What about when you are not moving fast, and need to turn? Let's see... One hand on the steering, and one on the crank.

No one says I need to complete a full revolution on the cranks. I can freewheel back and repeat. Or crank a full rev. Either way it is not a big deal.

In the YouTube videos of off road handcycles you see this happen when they climb rocks going up a steep incline with turns and such.

Andrew R Stewart 

+1. And I'll add that there are many times that I want both steering and propulsion at the same time.


Interesting how as this design develop it gets farther away from a simple cutting up of a couple of bikes... Andy

AbiliTTV

Andy, you have no idea how frustrated trying to get both pedaling and steering in one without lengthening the frame...

I reread: +1. And I'll add that there are many times that I want both steering and propulsion at the same time.
And, something clicked. A way to make a slight change to my steering design and presto I will be able to provide both. Thanks for that info. Because, I would most likely be thinking the same thing.

It will still use cut up bicycles. It will use the center piece of my weight bench for the center frame. For the front arms - they will be the down tubes. The kingpins are the header tubes/necks of the bikes. The seat back of the weight bench. The seat pan will be a tractor seat. The crank support will be the top tube with the seat and its down tube with quick connect for adjustment.

The chain guide will be using the rings from the handcrank, the rear assembly will be the rear triangle of one of the bikes. One det of handlebars will be cut to attach to the handcrank. The second will be the under the seat steering.

Forks will be used so I may mount front brakes.

Most of the same parts will be used as before. Just in a much more efficient way I feel.

AbiliTTV

OK, it took me a little to get what you mean about it is more than cutting up some bikes to build this.

From my train wreck of a first design, and several using the dual control set up. Thank you Andrew R. Stewart for your personal input bro. With that I redesigned the front end. No longer to the front arms stick out in a strange way. They now are to the sides.

The steering was so simple, kind of like post it note simple. You will see now the dual control set up is gone for good.

Now the steering, and all other controls are on in one. The crank down tube is adjustable in height, and can pivot to get the cranks into that perfect sweet spot for me.

I am now using two shorter steering rods. And, this new design will keep the steering tighter to the underside of the frame. As such so will the chain management system (to be redesigned on the fly).

I was able to put in two foot/leg positions I may add one more.

Steering now is more like a car, and the outright arms are longer than the half of the front wheels so they will not hit the frame. I was able to shorten the center frame by a foot or two. Trying to keep it a short wheelbase.

The steering will lean the bike into the turns, and self right itself.

I may order a 3 speed internal shifting hub for the rear wheel to get a lot more gearing options, and those can shift with out moving.

So 21 Speeds Plus 3 more on any of the gear rations I can use... Anyone know how many gears that makes?