I expect when I turn using the design I am planning, more than likely my hands or hand depending on the situation will not be pedaling. I will be turning, then when I straighten back out I can return to pedaling. Hence why the forks out front. They want to stay straight until I apply force to them. Once I am done they will right themselves. With the forks more traditional placed I need to keep one hand always on them to keep them straight more than likely.

Also one wheel turns faster on my wheelchair every time I turn as it is. Also I can not use the full wheel to push with. In the above photo of me an post you can see how much weight is an issue to me.

As for the ration of the wheels on my wheelchair you see my hands at the top of the push in the photo. The end of the push is at the seat pan. This is about one quarter of a turn using pedals.

With the cranks placed as I have them, as these are used for foot pedals I can go full circle, or half way and push, much like using levers. They offer a few pedaling options. Row style, alternating, and either in half circle pushes.

I am trying to work out a return to neutral center for forks placed more upright. I may use this method to connect and steer with in a modified fashion. Placing the forks back to normal positioning.

[MENTION=84476]cny-bikeman[/MENTION] I have a feeling if we lived next door or close by we would be friends. I say this because I am really enjoying our conversation here.

I am used to turning arcs as my wheelchair wheels do this also.

Pushing the pedals a quarter or half turn freewheel back and repeat the push. Almost like putting hand to wheel to push . In fast turns I don't push all the way. I go about half a normal push and let go, then repeat. As the outer wheel is moving fast enough if I push as normal I would be yanked out of my seat. So I do much shorter but faster hand movement So I am very used to being the differential for my drive wheels.

But, since the turn should require my hands on the hsndlebar most likely I would not push. At speed the weight will keep me moving through most turns. Using momentum to my advantage.
At slower speeds I can easily keep up with the outer wheel using cranks like shown as a lever type push.
Images explained next.
I am posting some images, levers actually make the most sense to use and hand propulsion. Notice they are where my dual drives are. Sane exact physics here in turns and all. One pumps faster than the other. As they are the same at the wheels. So these aspects don't bother me as I live with them daily.

Rake to the forks - LasherSport Sports and many others chopper rake all the time and have no issues. In the image with the off road dream machine I would love to at least test ride.

LasherSport ATH-FS with custom 29er+ wheels and 3" wide tires. Ready to find some gnarly single track out of Blue Diamond in Nevada. This may even be extreme enough for [MENTION=82462]RobD[/MENTION]yrdek to take for a spin.

Notice the rake on that beast. That is why I like that fork placement. While my use is not for the extreme riding the ATH-FS is at least I know I can steer. Also when I let go of the handlebar my steering returns to straight tracking.

In the image with the blue framed bike seat at the rear axles, my weight will not affect the front end to the point it doesn’t touch the ground.

My balance point is based on years of my balance point being just about that same position for my wheelchair. It is my comfort zone.

I got to looking at handcycles with more upright forks almost all employ a centering spring to allow the wheel even with hand controls on the front steering to return to center. Seems that the front wheel may be to much like a caster and needs some force to keep it tracking straight.

I can employ a spring system if I do not rake the forks.

By now, it should be obvious, brakes yes , with dual cable ends..

shifters NO,, you must bodge something together on your own...

I agree we could be friends. It's rare to find someone who does not take negative feedback or opinion as a personal attack.

However, I still have serious concerns about your plan. Pushing the driving ring on a wheelchair is not analogous to turning cranks in a circle or even an arc. You can grab the ring anywhere, and can use them to propel, brake and steer, and again you will not be able to use your muscles nearly as efficiently with your concept. The levers you show on the Wijit wheelchair system are much longer than cranks you would be using, and the Wijit's design incorporates braking and shifting on those same levers

The shifting is going to be a big problem. Even if the cables move the same that does not assure shifting is synced, as no two drive trains are the same, and the rate and force with which you rotate each crank will affect the shift timing.

I have not seen a single picture of a 4 wheel, hand-driven vehicle, nor one that has such a questionable separation of propulsion and steering/braking functions, nor one with two completely separate drive trains. There's a reason for that. If you look at the history of human-powered vehicles you will find a huge variety of ideas, many of which did not survive. Of course there's nothing wrong with you investing your own time and resources, even if it fails, and I do commend you for trying to craft a more affordable solution.

It is nice to be discussing things as this is,designed for. And, your correct about everything you are saying.

I do not need to worry about grabbing my wheels at exactly precise locations to make them work.

And, the lever systems all of them are like the ones I show here. Each its own system able to do all functions in one thing.

And, correct the arc and circular motion of a crank system are different mechanics.

You are correct I have seen some oddball propulsion methods for human power vehicles. Non I have seen provide a goofy drive train like my dual one.

And, totally agree the two while similar are not the same. One will always move and function better than the other for any number of reasons. Friction, amount of lube used, to difference in materials and craftsmanship if you can call Walmart quality crafted. Lol Chain length, inflation of the tires and on the list goes.

I do like the tabpole design over the trike. If I can figure out how to use one drive I may be able make it work much easier.

Back to the drawing board. Lol I love this though. You are so kind to be so honest like this. I personally dislike and distrust mist people who are anything less.

I will work on a single drive 3 wheel design now, just because you are correct about that shift issue I would face. Even with dual controls separated the out of sync shifts would drive me insane. If I am not already.


I can not express how glad you are here. I don't want to build a lemon. Even if it is a tank. I want a working tank. Lol

3 Wheel 1st Version
 

THE MODEL IS NOT TO SCALE - That means it will look like it won't fit a human rider. When I go to build naturally it will be adjusted to fit me.

This is the napkin drawing a rough idea. Also the steering is not rigid, it employs a header tube and is connected to the inner neck portion. I am using the rear triangle in the front as forks because it has both front and rear derailleurs.

I also will be configuring the hand pegs on the crank to hols the handles with brake levers, gear shifters by cutting the ends from the handlebars and attaching them to the free spinning hand pegs.

The rear employs dual front forks to allow the wheels to have camber, this will help keep me table in turns better than having them up and down.

At this time no foot placement has been working in yet. Why? Because I can not ride with my legs out in front. So I will need to design the foot rest in the real world.

As far as weight goes - This design will weigh only a few pounds less. So no real gain in the weight department. And, I really do not care what this weighs.

On the cranks you see a dozen or so other cranks minus handles... This is to show the rotation. Also the down tube(s) will be positioned in place to the cranks do not touch them while turning.

The seat in the images shows the down tube going through it. This will not be the case in the final build.

In the rear you may be wondering what is the extra framing for? Since I use a wheelchair to otherwise walk around. I need a place to tow it from. The front casters will rest in this extra framing to be adjusted to fit in the final build.

Personally I like 4 wheels better than tree just a personal preference. My next fave is two wheels out front, and one in the rear ( tadpole). I will see if I can work out a design for a tadpole.

But, as for mechanics go - this 3 wheeler actually would work of course adjusting it to actually fit a human rider. No annoying dual drive issues.

But, as far as costs go they remain about the same. I still need two bikes, and a seating system. At roughly $360 to $450 for this entire build using all new retail priced parts, source bikes and such - you would be hard pressed to build a handcycle for less using the same methods I have.

I want to be able to show with a proof of concept to the naysayers that it is possible to build an affordable handcycle, and keep the retail price for a new casual use handcycle at $1000 or less.

My images are larger in most cases than the limits the site puts, so they will appear squished in some.:bike2:

I don't have much to add, but this is one of the most interesting problems I've ever seen discussed in here... so thanks for that.

Are you doing anything funky with the threading for the crank on the left side to approximate a tandem's stoker crank? Otherwise you'll have the chain rubbing on your left shoulder.

Nice catch with that. Yes, I will employ a handy ring/chain guard.

I have found an image if about how I will sit. Minus I will have my legs down away from the front if possible. But, the image really shows how a person fits behind a crank like this.

OK, so normal crank with a guard to protect your left arm, that should work fine.

Logistically, how do you plan to get into the saddle? Will you be able to transfer from your wheelchair without help? I wonder if there might be a modification that would make that easier.


http://www.bikeforums.net/attachment...1&d=1503797186

Not related, but there's a guy with a recumbent hand cycle and a hub motor who rides up the local mountain. Check out the video in this blog post.

http://diabloscott.blogspot.com/2017...17-smr-19.html

Transferring for me is no issue. Even with an annoying frame like that. I have realized with the help of other awesome people on here that my idea for a dual drive won't sync as much as I would love it to. Darn those things. LOL I resolved this with a trike style my least liked design option. But, it would work at least.

I am now trying to design a tadpole two wheels up front with the drive wheel in back. Going to take a really long chain however. LOL I will see what I work up with the parts from the two bikes. Also, sorry about the squishy image. The angles are much nicer than they appear. And, the down tube will be adjusted to fit my transfer needs.

My biggest puzzle was trying to sync to shift systems so they work as one.

Chances are the neighbor who wants to help me weld this all together will have plenty of ideas also.

Want 2 in the back, get an adult trike to cut up , the ones with 2 chains , you can put as they do a loop of chain instead of going into one cassette gear, have the end cog driving the axle to one, the right hand wheel.. or a cog on the hubflange instead of spokes.

Brits have racing trikes they have the same on drive 1 freely spinning wheel on the back.

you are just lowering the seat to corner better.. apparently..






...

@fietbob I love that idea also with the trike idea.

I did not know :saweeet:the Brits race trikes, I will have to check that out. I love learning new things. Especially when wheels are involved.

Lowering the seat yes to turn better is correct.

Here is my other design idea it is a tadpole style rear drive. This kind of works like the you mentioned a loop to turn everything and a shorter chain to do the gear changing. The loop chain will need to be rather long for this to work.

The wheelie bar in the back is the wheelchair tow point.

And, the handlebar is connected via pivot points that would use sealed bearings as the point of friction. Cranks are to just pedal with. I could I guess do like I did for the trike design and add them to the handles on the crank.

I believe the front forks are at an angle that will turn with the connection as shown on the dual front wheel mountain bike several posts up now.

Also to everyone who is partaking in this, I am so glad you are. You brought to my attention my ignorance on the dual drive set up. I would rather redo the 3D model many times over and get it right when the build happens. Instead of build a turd of a design that looked good to me.

Thank you all and to anyone else that happens to join,

With as much trail as you have in those forks, the trike is going to REALLY want to go straight. It'll be quite difficult to turn and the handlebars will snap back to straight very quickly. I mean, assuming 26" wheels we're talking at ~12-13 INCHES of trail. That's ~330 mm of trail, compared to a normal amount of ~40 mm to 70 mm.

EDIT: I think i've got this backwards. I think more trail = more floppyness, I always get it wrong, but don't feel like correcting it.

Raked forks is one way to insure I can remain tracking straight while I pedal. No worries about turns, I will be hands on handlebar. As I leave the turn I have the option of letting go and returning to the forward tracking with out the annoying need to always keep my hands on the wheel so to say.

Here are some beautiful examples of the raked fork. Or trail (first time hearing it called that. I learned something new.)

I am using physics to my advantage. The amount of force to turn and hold should be way less than on these examples I show.

OK, this is really cool. I never even knew this sport existed. IMPRESSED

In my case if I sit that high up, I do not get the advantage of shifting into a lean like that. I would need to slow way down to make a corner like that. Or tip over.
Wish I knew about these when I was able bodied.

What if the fork is reversed? That will knock of some trail, I think. The brakes would be going the wrong way, but would that matter?

I just found Jet Bike plans for a tadpole level steer. I can adapt it to use the parts I will have. Jet Bike is an open source design with free plans. Talk about cool.

The design they have is all tilting an automatic self centering. In both Tadpole witch I like best. And Trike.

EDIT: Jetrike is the proper name of the site and designs offered.

OK - Working on the final design. WOW I never expected it would turn into the machine shown here.

I have to thank every person who posted a reply to my original post here. I went from a rather silly (stupid) design idea to a Tadpole with ackermann steering. Also included are many more little details such as one tie rod and a steering rod.

About this design -

You will instantly notice the forks sticking straight ahead only the top is out front. I did this so I can mount V Brakes or caliper style brakes. Yes, it adds weight. But, notice the lack if huge down tubes blocking my view. With the kingpins set as they are on this it will cause the entire bike to lean into the turns rather than remain upright.

I have made the handcranks adjustable in height by using the seat post and the lock mechanism on the seat tube. This will allow for some up and down adjustment. Then I made the tube pivot in the base, and a pivoting support tube that will slide and lock in place using one of the weight benches locking pins. If that won't work then a bolt and cotter pin will do the trick.

The seat will be on a plate that is on ball bearing slide rails for ease of movement. Same idea to lock it in place for adjustments.

The rear is the entire triangle of the back off one bike. So the entire shifting system remains as simple as possible. The long chain or first chain will mount on the other side, using the large ring from the other bike I will mount it only to the handcrank. I will use the middle or find a smaller cog to place a bit behind the under the seat handle bars. They will be connected to either a bolt and some bearings to allow for a snug fit yet offer smooth movement.

The long chain goes down in front between the V arms in the front. I used a large cog to allow clearance of the steering rod. When building the actual bike these areas will be adjusted to better sizes. None of this is to scale.

I hope is the provide two points to keep the chain in control and use springs or a damper of some sort to keep the chain at the proper tension at all times, and for all adjustments made to the cranks.

I did research on what a JIG is. and will for sure be building and using one or maybe more to keep this all in line and straight tracking. Nothing worse than putting all the time in and roll down the road with your tail next to you. Only slight embarrassing.

Now I have redundant brake levers on both hand holds. The Handlebars are on a pivot. The hand grips will be on the spinning part of the pedals. I am getting pedals I can remove the foot rests from.
So these will pivot and remain in the comfortable positions as shown. So yes they are going to be screwed into the spinning center piece over the spindle of the pedals. This allows the cables to arch away and not risk breakage as easily.

The gear shifting will be only on the handcranks as that makes the most sense sense I need to be moving the chain system to change gears.

All three wheels will have brakes, and both sets of brake levers will be in effect working the brakes. In case I need to stop with my hands in either location. No need to grab for the brakes and crash.

Many of the details are extra out of proportion as this will serve is my over all end result I want. While working with actual plans for a tadpole recumbent and adapting them to my parts.

Again, all of you have really helped me end up with what I feel will be an awesome bike. I am currently saving my pennies to buy the required bikes for this.

Total Cost as of right now about $100 for the tractor seat. More comfy on my back witch is at level 8 to 10 pain 24 -7 365. And, the weight bench. When done before paint or powder coat: I will be in for about $360 to $500.

Cost to buy a seven speed recumbent used maybe $500 plus shipping another $100 or more.
Cost to take it apart, and modify it for my particular sitting needs... Another $500. That may also include figuring out how to make it 21 speed also. So it ends up more for me this way. I rather build my own, even as a first timer.

I would do disc brakes if I could afford them. I may upgrade down the road.

I will continue to work out the smaller details as I know that is where the devil is. Also I have added a chain guard to you know make this look even cooler.

ALSO if the images appear squished, that was me uploading a larger image than this site prefers. Sorry about that.
In this design I did plan it out around me sitting in it. I did not include that model just so it us easier to see things. I may sneak digital me in one of these times. :)


What you see as rivets are actually holes along the frame to allow the seat, and handcrank to adjust. Others represent bolt ends and one as a quick release on the handcrank stem. Reusing the seat post and its quick connect.

The program I use to model with from what I know doesn't do what CAD does. It is not precise and offers no measurements of things. I use WINGS 3D it is lightweight pretty easy to use.

If anyone knows of an open source program to simulate chains and gears moving, that would rock. Same thing for steering simulation, so I can be sure that my steering arm won't hang on one of the gears/cogs on the underside.

Hope you can see the progress made to reach this point.