Thread 2937796

Dia dhaoibh,

I've taken an interest recently to recumbent bicycles and velomobiles/streamliners and have some thoughts I'd like to share and would like to get some opinions maybe. My idea for a very low maintenance recumbent would involve a direct drive 7-13 speed IGH on the front wheel, which would remove the use of a chain altogether, as well as back wheel steering. It would look very similar to the chopzone marauder lowracer: https://chopzone.com/content/plans/marauder_lowracer/marauder_lowracer.htm


I currently only see 2 issues with this:
1. No such internal gear hub exists as of yet according to my research, meaning I'll have to make it myself.
2. This would be a very low bike, which could cause safety issues if used on roads with cars.

I don't think back wheel steering is a huge deal and imagine one would get used to it very quickly, so I didn't include it as an issue.

It's also very likely that this sort of bike would have an electric back wheel which would also make it both wheel drive in a way.

A fairing of any sort could be added to this in theory but I would like to keep it cheap and am holding onto the idea of using some sort of tent pole/windproof fabric as a fairing instead of fiberglass.

Finally this is all to say the overall price of production for this bike would probably sit cheaper than a standard upright derailleur bike, at least I would imagine.

Any notions? Go raibh céad míle maith agaibh.

>>2937796 (OP)
There have been plenty of examples of conventional IGHs modified to do exactly this and unicycles and such.
>rear wheel steering
EASE. FUCK NO GOD WHY
honestly connect a few chains and run that boom to rear wheel. Really.
>safety issues
as if the cager was ever not out to either 'accidentially' or if feeling certain they arent being watched intentionally maim and kill you. Wether youre on an uprighg or not.
>get used to it
have fun. Maybe go fast in a combine or forklift for a dax and see how much you improve by the end of the day
>electric
if this was /n/ i'd tell you to >>>/o/
>fairing
fairings are cool, can be had super cheap, are very efficient, can shelter you from the elements and the limiting factor is ventilation and not cooking off inside of there even in winter
>cheaper
nah. The cost is in the components. Headset, IGH, shifter, wheelset, brakes, cranks, pedals....
>irish
go back to drinking

>>2937796 (OP)
The stability of rear wheel steered bikes is terrible, they are inherently unstable in most configurations. Some configurations can be ridden (eg some people ride their bmx backward but they move all their mass to be above the front wheel) but it takes full attention and you want to be able to move your center of gravity wrt the bike (which you can’t) and even then it takes lots of learning to make even a small controlled turn. Think ‘very big slow circle in a parking lot’ not moving swiftly through traffic. There’s a paper by AL Schwab that goes in to the dynamics and stability if you want to read more

>>2937796 (OP)
>I don't think back wheel steering is a huge deal and imagine one would get used to it very quickly, so I didn't include it as an issue.

It's a colossal issue. Consider what happens when you turn on a front-wheel steering bike: You lean inward, and turning the front wheel forces the bike under you to be directed toward the inside of the turn. Effectively, the bike is trying to move under you to correct your leaning.

On a rear-steering bike, the exact opposite happens. The rear wheel turns outward, which tends to want to pull the bike out from under you. It's technically rideable, but it's inherently a much less stable configuration. Even in 3 or 4-wheeled vehicles, there's a reason rear steering isn't used. Forklifts are about the only thing I can think of where it's common.

>>2937804
>There have been plenty of examples of conventional IGHs modified to do exactly this and unicycles and such.
I've seen some of those but haven't noticed any more than 3 speed.
>as if the cager was ever not out to either 'accidentially' or if feeling certain they arent being watched intentionally maim and kill you.
In Ireland it's not really that bad and it's pretty good in city/suburbs, so I think visibility is actually important.
>>2937843
>>2937838
>rear wheel steering bad
I still don't quite understand this, why is it so bad? Can you really not just lean into turns preemptively for example? It sounds like it could be disorienting but not just pure dangerous. Here's a video of a similar idea, main difference would be the direct drive https://m.youtube.com/watch?v=nugn2DbL-uw
>fairings are cool
Didn't know they were cheap, always guessed based on velomobile prices that they were difficult to make/expensive in some way, no experience with fibreglass so not sure what the process is like, so I thought a fabric equivalent that weighs much less but keepa the weatherproofing would be a good idea.
>go back to drinking
I don't drink

Go raibh maith agaibh as bhur gcabhair.

>>2937838
>There’s a paper by AL Schwab
I'll look for it and read it when I can, cheers

>>2937859
The whole point of that project is let a team of engineers design and build a usable rwsb over the course of a semester and it’s still super wobbly.

There is a number of issues, if you are close to the rear wheel, the frame sends your body in the opposite direction (outward) from where you want to go. You need to somehow send the center of gravity back to the inside but guess what you can’t really move while reclining. The guy pre empts his turns by throwing himself to the inside has he steers, then lets himself fall for a bit, then throws himself back up.

It is possible but on a front steered bike it takes almost no attention and it self corrects, small disturbances are damped out and bike goes back straight. On the rear steered one you need to correct any small disturbance actively, forcing you into a turn, and if you’re only a bit too late, dropping you off the bike, so even with 100% muscle memory it will still take three times as much effort and attention.

They were used for speed records on very flat straight tracks as front steering ruins aerodynamics but with the introduction of light carbon fire fairings/hulls they fell out of fashion for that too

>>2937869
>it’s still super wobbly.
The same channel has 4 other videos where he rides it quite smoothly.
>the frame sends your body in the opposite direction
Right, I see.

I may just do it as a personal bike project in that case, I still like the idea but yeah I see that actually.

Go maire tú i bhfad.

You're kind of trying to solve a problem that doesn't exist. Swapping drive & steering front to back provides no benefit while making it much harder to ride.

>>2937879
The "problem" I'm trying to solve is the long chain going from the front of a recumbent to the back wheels. If instead you use FWD, you lose out on steering range because now you turn the pedals with the wheel. So to make it that you can keep your FWD and steering range, you put the steering in the back. It isn't really a problem but I would personally like to see how it would change things, mainly the fact that the front wheel would then hold all things for propulsion, no chain, no sprockets, etc.

>>2937881
>The "problem" I'm trying to solve is the long chain going from the front of a recumbent to the back wheels
But that's not a problem.

>>2937881
It is not a problem.
you put a chainguide aka tooooob on,
only where it needs.
some guys use pulley instead because muh efficiency but its a meme you already shed all that wind resistance.
there is plenty of FWD designs that use short chain and fo front steering.
there is designs that have FWD, steer in fromt but the pedals aren't influenced by steering.
but you dont need that its a am meme. It's just OCD or perfectionism. In reality plenty of dudes do just fine with their BB on the steerer tube and the chain is short.
Regarding the IGHs: I dont remember how many gears some random one offs I saw had. But I know I saw a rohloff used in this capacity at least once. and with the principle being the same it doesn't matter you can modify a 7sp like a 3sp.

>>2937885
I suppose but is a direct drive with no chain not cleaner? Removing a moving part that is visible. I also generally think it'd look better. Furthermore I'm not chasing efficiency because as you said I've already shed all the wind resistance, I am however chasing ease of maintenance, and a bike that doesn't have a chain and has an IGH sounds like a fairly maintenance free one.

>rohloff used in this capacity
Interesting, I'll look around to see if I can find that.

>>2937897
>I suppose but is a direct drive with no chain not cleaner? Removing a moving part that is visible. I also generally think it'd look better.
So this isn't about functionality, it's about aesthetics.

>>2937897
>I am however chasing ease of maintenance
How much maintenance do you think a bicycle chain involves? Spray it with a little chain lube like once a month and it lasts forever.

>>2937906
Sort of, it's meant to come out as overall cheap and never needing to be touched, while still looking nice. I should also mention that a chain could also catch in clothes which adds parts, I want it to be as simple as possible. Also once month is more than never, that's the idea, I'ven't a clue how it'd play out in reality, however.

>catch in clothes which adds parts
by this I mean a cover for the chain, but I should also mention that bikes don't have many parts and removing another, even if it's so simple, would make production and maintenance as a percentage quite a bit easier

Every person I have ever known to ride a recumbent bike was a closeted faggot music teacher...

>>2937897
Okay look my friend.
The bicycle is and always has been a fascination and fetish object for many. Myself included, sitting on show bikes,fun bikes, meme bikes, recumbents, race bikes, sports bikes, utility bikes and so on. This means that millions have thinkered with bicycles, put mind to it and tried to do it differently, reinvent it... and all the things being discussed ITT have literally been done thousands of times. And yet we see a few basic designs popping up over and over again and designers always, ultimately, gravitating to those few basic designs after trying all sorts of things. Just like I gravitate to my absolutely plain, cheap and boring commuter every single morning. Becauae those things just work.
Those things are compromises. Sure. But compromises that give you the best overall experience.
Having the BB axis turn in with the steering: Not a problem it turns out.
Rear wheel steering: A problem, as it turns out.
Chains: Not a problem, works great. 500+% range. Pedals position independently from the front wheel. Nice.
Electric motors and motors in general: Negro fag shit it turns out.
Super long chains and rear wheel drive: Really nice, turns out you can climb on that shit. Have fun being seated in a reclined seat with your front wheel slipping and you realise you have no way to get your weight up there.
Etc. etc. etc.
Let me ask something else. And I mean this:
Have you built a bicycle?
Do yourself the favour: Build a bicycle. Nothing special. Single speed, 75 parallel, structural steel & NO BELLS AND WHISTLES.
Get a drivetrain, wheels, headset, fork, brakes, seatpost, saddle, etc. and get the usual tubes but go for cheap structural steel. You wont get the bicycle specific dimensions but buy 28mm for example and pay with wall thickness and weight for the lack of strength. We're not building a racer but a standard bike here. Get 5mm plate to make dropouts and a bridge. Buy tbe BB threaded, save yourself the trouble.
Plan a NORMAL FRAME....

>>2937927
Cut mitre and weld or braze your stuff together. Doesnt matter if you stick, tig, wire or brass braze it. Just get it done. Assemble it and ride.
There. You have built a bicycle. And after you did it once you'll hsve a clearer oicture and the next one is a matter of 3 days.
Then go from there. This is honest advice. Avoid paralysis by analysis. You're just delaying building your bicycle by going back to the design phase and making changes to parts of your design that you probably have no experience with.
Do normal first. Get going. Then start doing the whacky stuff and finding out why its one-dimensionally cool on paper but not competitive with the accepted ways of doing things in practice.

>>2937917
I am neither, however I do not ride a recumbent, yet.

>>2937927
I have not, and I understand the idea of starting with the default, which is what I plan to do, before then moving on to this project, but I would like to comment on something crucial which I think you may be missing on your first point, which is that, from what I can tell, recumbents are unpopular because they're expensive and/or dangerous when around other cars, FWD doesn't really make sense on an upright, and neither does rear steering (which I've conceded is generally just worse than front steering), so for a personal bike, which will be used only on greenways (cycle/walk only areas), and which seems more interesting with rear steering, I think I'll still, after some time and other projects go on to try this. Also I'm not sure why you dislike electric motors, if it means I get to get to work without needing a shower I'm all for it, and an e-bike does just that.

Gurab agaitse mórán sláinte.

>>2937930
Right, I know what you're talking about, I'll be doing that anyhow, so thanks a million for the advice

>>2937930
Brazing is extra nice because if you want to change something you can easily thaw the braze with your torch, remove or reposition parts then braze them in place. Braze joints tolerate shock well hence their use in steel rule dies for cutting tough fabrics using a motorized press. Motorcycle frames including Harley were brazed for many decades and breakage or joint failure was not at all an issue.

Brazing is easy to learn and your torch can also weld (including aluminum), cut, anneal, temper, gouge, heat thick stock for easy bending by hand, wash off stuck nuts without damaging the bolt or stud they're stuck to (takes practice on scrap but well worth learning), burn out stuck machinery pins and more. No shore power required.

Quality used US-made torches and regulators frequently outlive multiple owners and are easy to overhaul or send out for overhaul/repair (but I only do that for oxygen regulators which are crustier than I feel like polishing).

I've only my DC TIG to my name, but that should suffice

>>2937934
go to >>>/n/ if you seriously have an interest in answering why using motorized means of transportation might be undesireable and shpuld be reserved, if at all, for the weak, elderly, children, women, negro, feeble minded and what not, because we, white men, have created a world that they unfortunately have to live in and this world demands a certain need for mobility that may be, for some, beyond their limitations in physical or emotional strength or motivation.
>after some time and projects
I did not mean to discourage you. Also I was making a generalized point. Maybe build a lowracer, very close to the example of some build log you find online. But do build something that is proven to work. Before building what you came up with, you'll find yourself in a situation whete you dob't know if, for example, your recumbent seems unrideable because of the geometry or because you have no experience riding recumbents. You'll try to learn riding a recumbent knowing it might very qell be the recumbent, not you. Just abother example to as why not to go full creative mode right away.
Recumbents are easy.
Get square toob. Structural steel again. Make a backbone. Attach a boom with the BB on it. Put a front wheel in front using a nornal fork (see how you didged another problem). Make a seat from sections of pool noodle and upholstery, seriously. Get a rear wheel for the rear. Look online how people route their chains using idlers or hoses. Immitate that. It's really that easy and fast to do.
>expensive
low demand - > boutique - > expensive
>unpopular
I think it has alot to do with memes. The bicycle is a meme. The double diamond frame is stuck in peoples heads. It's a cultural thing. Also Fred rides that because Fred, whike he never races, wanta to ride what the pros ride. Etc.
>dangerous
see above, the cager is out to maim or kill you regardless of what youre on
>>2937961
yeah all my toeches are oversized for the brazing I do but i have cutting inserts up to 700mm...

>>2937961
... and the cuts are just fast and safe. Also using propane only. I have ace but I don't use it. I tig if I want to weld. Propane cuts and brazes and burnenates just fine.
>brazing is easy to learn
:)
>outlive owners
I dont even know how old most of my stuff is. Just make aure you got new hoses and up to date safety devices. Revently I was cutting and it wasnt thw hoses but same scenario: I forgot to do the nuts up on the torch end. Got lucky and notging happened.
>>2937965
Yeah that'll be perfectly fine. Welding is, for the most part, arguably the better process.
Brazing and bicycles is more a trad thing. The other thing is: You can flow brass through long lap joints. For welding yiud drill holes and do spots or such. You cant flow liquid steel through a gap in steel. So in those scenarios brazing might mean more surface area and ultimately more strength.
IMO the whole HAZ discussion and all is memetic. Weld up some thin wall 25CrMo4, let it air cool and that thing is solid. Same as brazed. If your design is really optimized the fuck out and on the edge of having any safety margin you're going for a full heat treat of your assembly anyways. Not me. I put toob together and happy.

>>2937934
>I am neither, however I do not ride a recumbent, yet.
Better study up on your music history and get a teaching degree...

>>2937975
Aah no I'm not discouraged, I've just got other stuff currently that i need out of my way before i progress into this