Recumbant Mid-Drive Scrapbuilt Buildlog. Pics & Questions.

[recumpence]

other Matt,

"So, are you kidding around, or is this truly a comment meant to be as rude as you are coming across?"

Needed a smiley face I guess.

Warren

Gotcha.

Just checking. :wink:

Carry on........

Matt

 

[Holocene]

Hi MCS,

You may wish to get the free BikeCad programs. There are several variants, and just the Pro version costs money... 8)
http://www.bikeforest.com/CAD/

Also, if you want to try riding a few different Recumbents, I'd recommend making a pilgrimage out to Bentley Cycle & Trading Post, just West of Gull Lake (North of Red Deer). Good selection of used 'bents there, available for test rides.
http://www.bentleycycle.net/

Good luck with your build, and have fun!

 

[www.recumbents.com]

Warren is a big wheel zealot, that's just his thing and I respect him for it as I do anybody else with reasonable yet differing opinions.

Matt, if you are building your own recumbent, here are tried and true plans to make a long wheelbase recumbent from scrap bikes:
http://recumbents.com/wisil/Plans/plans1.htm
Also see: http://www.recycledrecumbent.com

Other Warren.

 

[MattsAwesomeStuff]

You may wish to get the free BikeCad programs. There are several variants, and just the Pro version costs money...

Neat, thanks, I'll check those out.

I'd recommend making a pilgrimage out to Bentley Cycle & Trading Post, just West of Gull Lake (North of Red Deer).

That's a 4 hour trek out to a small town just to ride some bikes. In a city of a million people I'm sure I can find some locally.

Matt, if you are building your own recumbent, here are tried and true plans to make a long wheelbase recumbent from scrap bikes:

... But I'm not building a long wheelbase recumbent. I'm building a short wheelbase recumbent. I decided that from the start.

"I see you'd like to make some chocolate chip cookies, so here's a great recipe for apple pie."

The tutorials are in fact good, I read them sometime last month and they taught me some interesting things about making new bikes out of parts. The seat design I will probably be borrowing. But the rest of it just teaches me how to build something I decided I would not build before I started this thread.

 

[www.recumbents.com]

Hi Matt,

My mistake, how about this one? It handled well and was easy to build.

http://www.recumbents.com/wisil/junkbike/junkbike.htm
http://www.recumbents.com/wisil/junkbike/forrestbike.htm

-Warren.

 

[MattsAwesomeStuff]

how about this one?

I dunno let me look...

"The criteria to building the bike, is, well, to uh, not spend any money." <-- I like it already!

Not too much I can use, since you're reusing triangular frames, but, gave me some more ideas.

Power-side pulleys or sprockets are becoming intimidating to me, since people are suggesting they be 4"+. Hopefully I can get away without that. Second biggest concern is if I include rear suspension, how I will manage chain flex. The pivot will have to be between the crank and the rear wheel, so it will flex on the power side. I don't know how much, or how much is too much or enough to warrant a spring-mounted tensioning pulley.

 

[amberwolf]

For suspension vs chain growth, if you're willing to build the pivot point as a jackshaft, you can end the power side chain there and begin the wheel side chain at the same point. Then there is no problem, other than a very small efficiency drop from the extra teeth/chain friction.

Basically all you need is two sprockets that are joined axially, and both can ride on a bearing on the pivot shaft *or* on the tubing of one of the frame sections on either part that pivots on that point.

As long as the sprockets and the pivot share the center point, there's no chain growth, and no tensioner needed. .

 

[REdiculous]

Maybe, you're saying that I'll be gearing the motor way down to turn the big crank slow enough, which then turns the back wheel at a higher rpm than the crank?

Right. If you want the wheel to spin 250-500rpm, say, then why reduce the motor down to 80rpm just to bring the rpms right back up?

The right-angle looks beefy enough but there'd have to be a damn good reason to use it or I'd fine another way.

I went way off the reservation w/ my build because I wanted to see if my idea would work, and how well. Now I've got the most powerful 12v ebike on ES...lol...sometimes it's better if we just ignore the questions, advice and criticism so we can push on w/ the original plan. :wink:

 

[MattsAwesomeStuff]

As long as the sprockets and the pivot share the center point, there's no chain growth, and no tensioner needed.

Right right. But this is a contingency plan, 'cause I'm not sure I can pull that off. So, suppose I have to put the pivot 1" away or something.

 

[MattsAwesomeStuff]

A hundredpack of 10A anti-reversing diodes. I ordered these before I understood LiIon chemistry better. When hooked up one per series cell, these prevent batteries from being negatively charged via over-drain in series, by bypassing the battery if its voltage ever hits zero. I.E. They'll stop NiCads from ever being destroyed by being over-drained. But LiIons are already toast under 2.7V maybe, but certainly under 1V, let alone getting drained until negative. I might install them on my battery pack anyway (I'll need 42 of them if I have 170V) just because they're light, add no bulk and would prevent a dying battery from exploding.

Also, the 90-degree outboard motor gearbox arrived today:

It is a 2:1 geardown, and quite small. The bottom bulb is half the size of my fist.

One complication, it has no bearings, just seals, and the gears grind badly if it's not aligned both tilt-wise and depth-wise. This is a pain in the ass but not insurmountable.

So, the motor might be a little bit overpowered. Bit of a difference in shaft sizes here...

And the "completed" driveline:

Too much geardown as is. I'll have to remove, at least, one of the drill geardown stages.

As-is, with all 4 stage geardowns:

3200 RPM @ 130V.
90' gearbox is 2:1 so 1600 RPM.
The drill is 38:1 so 42 RPM
The drive sprocket will be ~3" and the rear cassette varies from 4.5" to 2.5", so, between 1.5:1 and 0.8:1, so between 28 and 53 RPM.

The rear wheel is 26"=0.66m or 2.07m circumference, so between 3.48-6.69 km/hour. Or, between a slow and a moderate walking speed. *Fail Stamp*

Kill one of the 6:1 geardowns in the drill gearbox.. 21-41 km/hour. Not bad. And if I use 170V instead of 130V like it's supposed to.. 27.5-53.7 km/hour.

Still a bit weak. I'd like a max speed a bit higher than that, batteries will drain too, so, maybe I'll upgrade to a 4" drive gear and increase those numbers by 33%.

Hrm, let's see if I get rid of the drill gearbox entirely, but pulse it on average at 130V still.. 126-246 km/hour (75-147 mph). Nope. Guess not.

4" drive sprocket it is. 37 - 71 km/hour (22 - 42 mph). Slower is not a problem, can do that electronically.

I guess the next step is laying it all out and start disassembling/cutting.

 

[MattsAwesomeStuff]

So I'm a bit stuck on what to do gear-wise. Maybe some of you with experience can help.

I'd ideally like to get rid of the drill gearbox entirely and just go Motor --> 90'. It's less weight, less bulk, less bracing, less machining, less figuring, less noise, etc. I put the numbers out there in the end of my previous post. But I'll update them presuming the actual battery voltage I'll be using. Let's deal in RPM rather than speeds.

Rear Tire RPM (26"), I want roughly 200-600. That's 25-75km/hour (15-45mph).

Wide open throttle, my motor spins at 4200 RPM @170v.
The 90 degree gearbox is 2:1, so, 2100 RPM. Those two are set and not changing.

I need somewhere around a 4:1 geardown still. Some of this could be done electronically, but I'd rather have my wide open throttle actually capable of hitting a high speed rather than never being able to go above a 25% duty cycle for example.

The easiest way is to make the drive sprocket quite small. How small could I reasonably make it? I've heard people say never go below 3-4", though I don't know why. I presume more tooth wear? The rear cassette will be a normalish cassette.

I'm also about to have a million bike-related questions about disassembly and connecting things and all that. But, baby steps.

 

[Lebowski]

don't forget that when you ask lots of power the motor will bog down by a certain %, so your
reduction should maybe be like 3:1 instead of 4:1 . I always liked the idea of using a read-axle
of a bicycle as a reduction axle. Drill out the spoke holes and attach a big sprocket. You can take
the reduced off of the X-mas tree (sorry can't think of the correct word right now). If you do
it correctly it will even give you a one-way freewheel so you can pedal without turning the motor
(for when the battery dies).

 

[MattsAwesomeStuff]

Drill out the spoke holes and attach a big sprocket.

The problem with this is that I want to actually use the rear gear, not have one big freak sprocket. If I was okay with a single speed, this would be fine.

I'm considering it though, because my motor is overpowered enough to slam its way up hills at speed without issue, which is the only reason you'd ever really need rear gears anyway. That and so you can pedal normally.

My motor can handle 2000-2500W continuous, conservatively (as in, that's what it's safely rated for).
Uphill 10% @ 50km/h (30mph) takes 2500W.

So if I go with electronic speed control and a single huge rear sprocket, I might never get into trouble. It's starting to get tempting.

But, more so interested right now in how small a drive sprocket could be.

 

[amberwolf]

I think he means to use a separate rear hub as a jackshaft, so that you have the freewheeling sprockets on one side and a fixed sprocket on the spoke flange.

 

[MattsAwesomeStuff]

I think he means to use a separate rear hub as a jackshaft, so that you have the freewheeling sprockets on one side and a fixed sprocket on the spoke flange.

So, moving the rear sprockets up to a middle place between gears, and then using a big sprocket at the wheel?

Well, the whole purpose of this is to eliminate a stage. I have the drill gearbox to geardown if I need it, I just want to eliminate a stage if possible.

 

[MattsAwesomeStuff]

Trying to get at freewheels. Bike question time. I'm a bike mechanic novice.

Here's a rear wheel from a Shimano mountain bike:

Here's the rear stuff from a single speed kid's bike (with backpedal braking):

Both should have freewheels yes? I can't figure out how to get them out/off.

I've read Atomic Zombie's tutorial on freewheel disassembly, but I can't quite put the pieces together (or in this case, take them apart).

I believe the top one is a cassette-style freehub, and the second is a threaded freewheel?

Help?

 

[Warren]

The top picture is a cassette mounted on a freehub style hub.

http://www.parktool.com/blog/repair-help/categories/cassette-and-freewheel-service

The lower picture appears to be parts from a single speed, coaster brake hub. No "freewheel" ratchet and pawl stuff in one of those.

 

[MattsAwesomeStuff]

Thanks Warren! I guess the whole cassette just slides right off the splines.

The lower picture appears to be parts from a single speed, coaster brake hub. No "freewheel" ratchet and pawl stuff in one of those.

So it's fixed like a kid's tricycle? There's no ability to coast? I figured it was a BMX type thing, with backpedalling to brake but still coasting when forward.

I have a couple others bikes I can gut for freewheels, I'll look into those next.

Thanks for the tutorials.

 

[MattsAwesomeStuff]

Update.

Mostly have been stuck on the gear ratio thing and not knowing what direction to take it. This, in turn, has been holding up any frame fabbing 'cause I don't know what will have to go where yet.

Progress:

- Stripped about half of the red (little, front) bike. Started at the back since I'm using the front as-is. Might use the rear gears/derailleur under the seat at the drive gears. Will use the (nice) brakes). Chain was great.

- Stripped about half of the blue (big, rear) bike. Rear gears are in great condition, long teeth and durable, they don't make them that way anymore. Rear tires are nice and fat, good for the weight. Left the rear as is and stripped from the seat post down. Tossed the crappy cantilever breaks. Kept the chain and front derailleur. Yanked the cables out, will re-use. Seat post came with a handy trailer mount.

- Got a chain breaker tool and figured out how to use it. Harvested 4 chains so I'm probably good for those.

- Sent an email to an electronics salvage place about reusing their junk laptop cells, no reply yet.

- Grabbed a couple dozen bearings from inside industrial copiers, none fit any of my shafts though.

- Took apart an old almost-junk grinder after I realized they must have 90 degree gearboxes in them, (it does, 3:1) and considered using it instead of the propeller gearbox (2:1) if I never add another geardown stage. But I couldn't figure out how to take the damned thing apart any further than the back casing.

- Did a COSTCO trip on a hardtail mountain bike and bought mostly canned goods (50 lbs worth). Threw them in the paniers and in a backpack and then kept my ass in the seat (no leg shock absorbing) up and down all curbs to see what 50lbs of motor/batteries and no shocks would feel like and how much fun it was climbing hills (what I'd be doing if the batteries died). Hills were manageable but I had to drop an extra chainring down. Square curbs are quite the crash down. Enough so I'm considering mounting the motor under the seat/top tube rather than behind the seat, to get some of the weight under the front shocks.

- Couldn't figure out how to get the cranks off their posts. Tried prybars and such. Bought a $10 gear pullet, but couldn't get the teeth in. Returned it and bought a $6 bearing puller that uses rectangular jaws rather than round ones. It just flexed and bent. Apparently there's a "Bottom Bracket Tool" for this. Some of my cranks are on shafts with a female (nut) thread, some have a male (bolt) thread. I hate buying 1-purpose tools, so maybe I could get a local bike shop to lend me one overnight. Stuck there.

- Tried to pull off the rear cassette like in Warren's linked tutorial, but they won't budge. I'm stumped, cone nuts are off, I can see clear through the other side.


It's not much but, seeing bike frames that are a lot closer to being used was encouraging.


Can anyone suggest what the smallest possible drive gear would be? I might just try going with electronic speed control and leave the bike geared for 125-250km/h WOT even if I'll never get close to it. I can't figure out a way to easily get a 4-5:1 geardown.

 

[amberwolf]

- Took apart an old almost-junk grinder after I realized they must have 90 degree gearboxes in them, (it does, 3:1) and considered using it instead of the propeller gearbox (2:1) if I never add another geardown stage. But I couldn't figure out how to take the damned thing apart any further than the back casing.

Post some pics, we might be able to help. Most come apart pretty easy, but also some of the cheap ones have so much lash (gear slop/wiggle) that if you really put a lot of power thru them you may well rip teeth off the gears with power from a bike motor. Also, they don't always use bearings in them, but sometimes just bushings, and those tend to be very worn in old grinders, and end up causing lash or other slop that wears gears quickly. I've got a harbor freight one that is trashed like that, becuase the bushings wore too much. Motor works great but gearbox is junked.

Keep in mind also that often the hsaft of the motor has one of the gears machined into it, meaning you must cut the shaft and create a coupler between it and the motor you are wanting to use.

- Couldn't figure out how to get the cranks off their posts. Tried prybars and such. Bought a $10 gear pullet, but couldn't get the teeth in. Returned it and bought a $6 bearing puller that uses rectangular jaws rather than round ones. It just flexed and bent. Apparently there's a "Bottom Bracket Tool" for this. Some of my cranks are on shafts with a female (nut) thread, some have a male (bolt) thread. I hate buying 1-purpose tools, so maybe I could get a local bike shop to lend me one overnight. Stuck there.

Many bike shops will take them off for you, but they usually charge for each set to be removed. Around here the going rate varies from $5 to $30, when I asked around before I just said screw it, and bought my own tool, because the tool can often be had for less than $10, which I think is about what I paid for mine.

The way it works is the cranks have threads on the inside of the hole surrounding where the nut or bolt goes in. You remove the bolt or nut using a regular socket wrench, then thread in the tool to those big threads. Tighten that down with the wrench (often part of the tool), then wrench the other half of the tool (usually clockwise, I think) to push against the threaded-in piece, which pushes the part you're now turning against the crankshaft (where the nut or bolt actually was at before), and forces the crank off of the shaft.

If you have any very large bolts with the same thread pitch and diameter as your cranks' hole, you could drill a hole in the bolts, and then tap them for a smaller but longer bolt to thread into them, and this will do the same job as the crank-removal tool.

- Tried to pull off the rear cassette like in Warren's linked tutorial, but they won't budge. I'm stumped, cone nuts are off, I can see clear through the other side.

First question: are you trying to get the sprockets off, so you can use them or the wheel hub (and it's built-in freewheel) separately, or are you wanting to use the whole freewheel mechanism on something other than the wheel hub?

I ask because that looks like a freehub type, using a cassette of sprockets that slide onto a splined section of the hub itself. The freewheeling mechanism is part of the hub, and is not easily going to be usable without the hub or at least some part of it.

Have you removed the locking sprocket(s) on the outside? Usually one or two of the smallest sprockets unscrews, or a separate lockring just outboard of all the sprockets. Depending on how they are made, it may require a "chain whip" to hold the other sprockets while you use the sprocket removal tool (splined with a nut built in for a large wrench) to loosen the small sprocket. Sometimes you just need the sprocket removal tool, turning against the locked freewheel mechanism (but it may require a very large amount of force / leverage to get it started--I've often had to use a hammer on the end of the wrench, while standing with my feet on the bottom edge of the rim to keep it from spinning).


I'll have to come bakc to try to help with the gearing--my brain isn't up to doing math right now.

 

[MattsAwesomeStuff]

I just said screw it, and bought my own tool, because the tool can often be had for less than $10, which I think is about what I paid for mine.

Yeah, that's what I figured. I bought a gear puller for $10 'cause at least it's useable as a gear puller too. Maybe I'll just buy and then return one if I can't borrow one.

then thread in the tool to those big threads.

Ahhhhh... the BIG threads. That makes more sense. I was thinking "Do I have to buy 2 different tools now, for the different small threads?". Duh. Great, thanks.

First question: are you trying to get the sprockets off, so you can use them or the wheel hub (and it's built-in freewheel) separately, or are you wanting to use the whole freewheel mechanism on something other than the wheel hub?

Either/or. General disassembly. I think I will have a single big gear at the cranks, and then mount a cassette under the seat (so I'll have 1 rear set at the rear, one rear set next to the power sprocket, coming from the front wheel).

The freewheel, I'm aware on this type is somewhat built into the hub, so probably not going to try too hard with that.

Have you removed the locking sprocket(s) on the outside? Usually one or two of the smallest sprockets unscrews, or a separate lockring just outboard of all the sprockets.

Aha. I could not find a lockring, and I could not pull the cassette off. I wasn't aware sometimes the small sprockets unscrew first.

It has spline teeth but they're only 1/8" deep. So chain whip (chain-in-a-vice for me, since I don't own a whip), and I'll make a spline tool from a bolt. I noticed when I turn them backwards it freewheels and presumed that must not be how they come off. Duh, gotta hold it with a whip.

Thanks again. Total bike noob I am.

I'll have to come bakc to try to help with the gearing--my brain isn't up to doing math right now.

I don't need help with the math. My question is related to... I see people saying things like, for power-side chain-redirector pulleys never go smaller than 3". I'm wondering about torque or tooth wear or anything like that. Like, any reason I couldn't use a very small sprocket, that wouldn't be obvious to me right away.

 

[amberwolf]

Ahhhhh... the BIG threads. That makes more sense. I was thinking "Do I have to buy 2 different tools now, for the different small threads?". Duh. Great, thanks.

When I first saw the tool itself, "Duh!" was exactly what went off in my head, because I had not figured out how it would work until that moment.

It has spline teeth but they're only 1/8" deep. So chain whip (chain-in-a-vice for me, since I don't own a whip), and I'll make a spline tool from a bolt. I noticed when I turn them backwards it freewheels and presumed that must not be how they come off. Duh, gotta hold it with a whip.

On the two cassettes I have here right now, both can be disassembled using the same splined removal tool that is used to take regular Shimano-type freewheel clusters off of thread-on hubs. I forget if I had to use a chain whip (chain screwed to the benchtop in my case) or not, on these, but on others I have.

It's not uncommon for me to find trashed bikes or wheels where the whole thing is rusted together, but I can still use sprockets separately if I can get them off--bolted or welded to other things for chain guides, tensioners, drive or receiver sprockets, etc. It's where I got most of the sprockets used on CrazyBike2's original powerchair drivetrain, and for the many failed attempts at chaindrive on DayGlo Avenger before that.

Thanks again. Total bike noob I am.

So was I when I started my quest almost 5 years ago...Sheldon Brown's site was the most helpful place for me learning the bike stuff.

My question is related to... I see people saying things like, for power-side chain-redirector pulleys never go smaller than 3". I'm wondering about torque or tooth wear or anything like that. Like, any reason I couldn't use a very small sprocket, that wouldn't be obvious to me right away.

Ah. Noise is one reason to keep pulleys big. The smaller they are, the tighter the angles between chain links, so the more they clatter on things they're going around. Also can cause more wear.

For drive and receiver sprockets, anything the chain is actually pulling on or being pulled by, the larger you can go the better, for power transfer. Otherwise it tends to wear things faster, or even slip right off if you are using derailers.

For instance, on CrazyBike2, using the Shimano single-speed freewheel, which I think is 14T (maybe 16, I forget) on the rear wheel, and the 48T or whatever it is on the front ring, I can pedal hard enough even with the motor putting out 2KW at startup from a stop to make the chain jump teeth (and this damages the teeth and the chain). So increasing chain tension by not using a derailer but just some other tensioning method would help that, but it might not stop it because the rear ring has so few teeth in contact with the chain. Using a bigger sprocket in the rear would fix it, too, but I'd have to super-size the front chainring to make up for that, and end up with one probably a foot in diameter. :lol:

 

[MattsAwesomeStuff]

Well, my source for dead laptop batteries didn't work out.

Sadly, that means this project is pretty much dead in the water for me, as, paying for batteries would cost more than a cheaper used motorbike.

A big deal on many of my project is the low barriers to tinkering. I never know 100% if it will work out, so I avoid spending. Also, I was interested in the whole "this was built entirely out of junk" challenge.

Thanks everyone for their feedback anyway. I have a couple more things to try but this was by far my best option, now sunk.

 

[amberwolf]

You might check stores that collect batteries for recycling, including toolpack batteries at hardware stores, places like Sears, Home Depot and Lowe's, etc, as you might be able to make a deal to take those away so they dont' have to deal with recycling them.

Computer stores and repair centers also often end up with dead or old batteries, and may be willing to let you have those, too. When I worked at CompUSA and Computer City before that, we would have given them to anyone that wanted them, as long as the manufacturers didn't require a return of them for warranty purposes.

 

[MattsAwesomeStuff]

You might check stores that collect batteries for recycling, including toolpack batteries at hardware stores, places like Sears, Home Depot and Lowe's, etc, as you might be able to make a deal to take those away so they dont' have to deal with recycling them.

Someone said Dewalt, I called, he said I could have all they have, and to check back in a while if I want more. Bingo. They're dead-ish LiFe, but, beggars and choosers and all that.

Computer stores and repair centers also often end up with dead or old batteries, and may be willing to let you have those, too. When I worked at CompUSA and Computer City before that, we would have given them to anyone that wanted them, as long as the manufacturers didn't require a return of them for warranty purposes.

These are the ones that are the least cooperative. There is an industry consortium that runs many of our provincial (and your state) "recycling" programs that is corrupt. Their goal is to destroy the second hand market by having free "electronics dropoffs" and such, so that people don't give or sell them away... so everyone has to buy new.

Even the "good guys" recycling programs, volunteer run charities, are jackasses. The big setback that had me discouraged earlier today was one big such group telling me if I wanted their dead batteries, $10 each. I was like "But, they're garbage to you, you're literally paying to dispose of them aren't you? I don't want the used ones that work, just the dead ones". Nope, $10 or stop wasting our time. Great, thanks, so much for the protecting the environment, maximizing re-use mission statement for this "charity". It was more the attitude than anything that got to me.

But I'll keep asking around for individual stores, maybe they're not as big of jackasses.