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Cheap Short Wheelbase Wood Conversion Recumbent Bike

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Picture of Cheap Short Wheelbase Wood Conversion Recumbent Bike
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Or CSWWCRB, for short.

Perhaps you've seen one or two in your hometown, or not at all. Recumbent bikes tend to have a (lets say) "mature" following as compared to it's traditional bike counterpart. Perhaps that's because 'bents are more expensive due to their comparatively low production volume. For this reason, you'll find a lot of people making home built 'bent frames and fairings.

For this project, I'm making a short wheelbase (SWB) 'bent on a very small budget and recycling components from other bikes in addition to a frame. I call it

The WidowMaker



I should mention, WoodenBikes.com is an awesome site worth checking out ;) If it wasn't for encouraging words from the site (and meeting/talking with the man behind the site at Maker Faire) - I would have been weary about mounting a crank in wood :p

One day, I want to build an awesome 4x4 tandem battering ram :D
 
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Step 1: Materials and Tools Used

Materials
1 Womens Beach Cruiser frame with rear wheel and coaster brake
Some pine 2x4
5 Bolts/nuts
18 washers
1 rear derailleur
Scrap .5" PVC and cement
Extra chain
20" wheel from a children's bike (optional)
1 piece crank from another donor bike (which also gave up chain and derailleur)

Tools
2 C Clamps
Adjustable Wrench
Saw
Drill and bits
Hole Saw
Chain Tool
Screwdriver
Hammer (for removing BB cups)
Measuring tape (for measuring X-seam etc.)
Something straight and long (measuring tape works)

Optional
Crank puller (or go to your local bike shop and have them pull your crank - for the non 1 piece crank guys)

There won't be any hack sawing, welding or irreversible changes made to the frame to be converted ;)

Step 2: Measurements

Picture of Measurements
First, measure your X-seam size. X-seam is the distance from your back to your feet in a recumbent (sitting) position. The best way to do this is to sit upright against a wall with your feet outstretched and measure the distance from the wall to your feet.

Alternativly, you can use two chairs. Sit upright in one chair and place your feet on the seat of another chair. Have an assistant push the second chair until your feet reach them. Then measure the distance between the seat backs.

This measurement simulates the distance between your seat and the furthest point on the crank.

Step 3: Harvesting

Picture of Harvesting
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You'll need:
1 piece crank and BB cups. You'll find these on most cheap American bikes.
Hanger mount derailleur (likely found on a bike with a 1 piece crank)
Chain How to Use a Chain Tool

Disassembling a 1 piece Crank
1. Remove the left pedal (left being the side without the chain rings - clockwise to unscrew)
2. Unscrew Nut on BB (the big one)
3. Remove keyed washer - it must be pulled straight out
4. Unscrew cone bearing race - note the two radial notches. Insert a screw driver and tap the retainer in a clockwise direction to unscrew.
5. Remove bearing retainer (use a screw driver to retrieve it if necessary - it will be greasy)
6. Pull the crank out (slightly) from the right side.
7. Pull right side bearing retainer out of bearing cup (to prevent damage)
8. Pull rotate crank downward so the chain rings go under the BB
9. Remove crank

Removing Cups
Take your screw driver and place it behind the cup, inside the BB (so to remove the right side, place the screw driver through the left side). Tap with a hammer - moving the screwdriver to different portions of the cup (top/bottom works well). The cup should wiggle and pop out.

Repeat for other side.

Rusty Chains
So you have a donor chain that's rusty - perhaps even really stiff? No problem :)

First - break the chain with your chain tool. Pre-soaking the link you'll be breaking with a little penetrating oil is a good idea. The link should also be able to move (even only slightly). Once you've got your chain, take it to the sink and wash any surface rust with soapy water and a scrubby. While washing, work the chain loose if excessive rust has seized the chain. when done, apply a light oil to protect from additional rust. You're not going to get all the rust off - but you'll have a free chain that works ;)

While using rusty chain isn't as reliable as new chain, it's free. I ride on once rusty seized chain - and have only had 1 chain break on me due to sub par chain assembly (I was excited and rushed and said it was "good enough"). But, if you want to go for "new" chain, you'll probably need about 3.5 of them (cheap chain will run you about $25-$35).

Step 4: Bottom Bracket

Picture of Bottom Bracket
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Start off by attaching a 10" piece of 2X4 to another 2x4. This is best done with bolts as bolts mean adjust ability. To ensure there's no chain ring path conflicts, trace the diameter of the inner two chain rings on your 10" piece of 2x4 (I got by, barely, with shear dumb luck) - also mark the center.

Clamp the smaller 2x4 to the longer one and drill three holes (that match your bolts) - do all holes at the same time. Then bolt together (don't forget washers).

You want the smaller 2x4 on the chain ring side


Now, drill a pilot hole through the marked center for the BB. Be as parallel as possible. Next, use a 2" hole saw (make sure this fits your BB cup) and cut a 1/2 inch deep hole. Don't remove any material yet (just drill the circle). Repeat on the opposite side.

Now, use a 3/4" hole saw and make two cuts to allow reassembly of the 1 piece crank. You need to be able to pass the crank/axle through the wood on that funny angle you used for disassembly. So make the cuts on "top" of each other.

Finally, chip away the 2" recess. Use a chisel, or a screwdriver ;)


Your cups should now press into the wood (perhaps slightly loose). Assemble the cups and reassemble the crank. You may find that the screw no longer fits with the keyed washer in place. I removed the keyed washer (which will require occasional tightness checks later). Re attach the let pedal.

Laugh at the hilarity of a bike crank assembled into some 2x4's.

Step 5: Conversion Frame

Picture of Conversion Frame
Start by attaching two long 2x4's to either side of the frame. They should run from the seat tube, through the headset and at least as long as the front wheel (we'll be trimming later). Fasten with a C clamp.

Now take your crank arm (boom) and slide in between the two long 2x4's in front of the front wheel. Gently fasten with a C clamp.

Using measuring tape, measure the distance from the seat tube to the furthest point on the crank and adjust until it matches your x-seam. Make additional adjustments to allow the crank to clear the front wheel - always making sure you don't go beyond your x-seam measurement (otherwise, you wont be able to reach the crank). Don't forget that you can swing the boom out in an arc and/or move the boom up/down. Don't worry about chain clearance just yet...


Once you've found a position you like. Take your drill and make three pilot holes. Two through the boom/outer wood bits and one though the long 2x4's near the seat tube. Drill your bolt holes and attach your bolts, tightly. Compression is what holds this frame in place.

As a tip, it can be useful to sit in the frame and gently rest your feet on the crank - to ensure your xseam measurements are correct and adjust if necessary ;)

Step 6: Chain and Trim

Picture of Chain and Trim
Now it's time to add your chain. You'll need to chain up your bike with some long chain you've put together - but don't close the ends just yet.

If the chain crosses the path of a turning front wheel, that could be bad. I'm using a derailleur as a chain guide. Simply add a bolt where you want to hand your chain guide from and string your chain through the derailleur as shown.

You can adjust chain alignment using the derailleur's shift adjustment screws.

Step 7: Final Notes

Picture of Final Notes
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Despite it's problems (mostly fixable - see below), I can do nothing buy smile while riding... And it is ridable :) My father, who has really never ridden a recumbent, got right on and was precariously pedaling away without falling :)

1: wheel size

Switching to a smaller wheel changes the steering geometry. If you go to a smaller wheel, you'll probably want to bend your fork forward a bit to make up for the lost trail.

2: Seat

Seat! Very important... My seat back is made from the original seat - turned vertically. This works very well. My seat bottom... I don't have one. I use a folded seat pad. When I come across some scrap plywood, I'll be sure to fashion some sort of proper seat.

3: derailleur

This sure does make things more complicated. But the original design called for the use of a smaller wheel and I didn't need this tensioner. Find a better tensioner if you can - this one is loud and doesn't work as nice as I'd like (but it was free).

4: Path

Double check that your pedals and foot path won't interfere with your front wheel. My crank just barely hits my front tire :( One day I'll fix that, but for now I just be sure to keep the crank out of the way while turning.

5: Weight

This thing is pretty heavy, and with a single speed - starting kinda sucks... Not too much can be done about that - just minimize material if possible, pick the lightest frame 0 money will buy.

6: Handlebars

1/2" PVC works great! Just be sure it doesn't get in the way of your knees. As shown, I'm using the original handlebars turned upright - but this forces me to bow my knees out while pedaling (not comfortable).

Accessories: Last Image

Turn the widow maker into the impalulator.
nice cycle<<
nanundo4 years ago
This's my inspiration I wish do this with my self
thank you.
John Smith7 years ago
Good Instructable. Is there any reason to choose a recumbent design over a regular one? Last pic of last step: Do I spy a Ka-Bar?
trebuchet03 (author)  John Smith7 years ago
Is there any reason to choose a recumbent design over a regular one?
If you've ridden a recumbent before, you either love it or hate it. Most people that are not already set into their hard core biking ways absolutely love it. There's something called the 'bent smile - because that's the only thing 'bent owners can do :p

There are hundreds of different recumbent positions and configurations - compared to the two triangle bike design that has been optimized for a VERY VERY long time... But the general benefits are:

More comfortable
Better for your back (with a proper seat)
You can be in a more aerodynamic position
Pedal force isn't limited to arm strength and body weight - you're basically doing a leg press into the seat as opposed to holding yourself down by the handlebars.

A draw back for two wheelers is hill climbing ability -- you can't stand up use gravity to put more power down. So on a hill, go too slow and you'll fall over. A trike solves that, but will very likely be heavier.

Not to mention every single speed and distance/time record was completed by a recumbent -- 81mph on a bike is nothing to ridicule :)


The biggest drawback is cost as they are not mass produced... bugger.
The speed records are on rather specialized 'bents... Complete with full fairings, lead vehicles to reduce air resistance, etc... And actually, the current "never mind the details" speed record (130+ mph) is held by a rather mundane "safety" bike, though one going steeply downhill. All the same, the speed records of any sort are so divorced from normal bike riding that it's hard to justify bringing them up. Recumbents have some ergonomic advantages, but also some practical disadvantages. Relatively poor visibility, in both the "seeing things" and "being seen" senses of the word, is certainly worth consideration. Riding a bike for utilitarian reasons---as opposed to weekend recreational riding---demands somewhat different tests of practicality. Recumbents have a considerably lower profile than the more common "safety" (or "double diamond", "triangle", etc) sort of bike, and this can result in considerably more risk when sharing traffic with autos. The lesser ability to deliver gravity-assisted pedaling power can also impact the hauling of heavy loads; though I have to admit I've never seen a recumbent designed for hauling heavy loads in the was the various "cargo bikes" or "longbikes" are built. But, again from a strictly utilitarian viewpoint, a bike that can't haul 100+ pounds without excessive effort is of little use...
trebuchet03 (author)  Cosantoir7 years ago
Complete with full fairings, lead vehicles to reduce air resistance, etc...

Fairings, yes - Lead vehicle to reduce air resistance - no - this is not allowed by IHPVA (the organizing association that runs the speed events) rules. They even have rules about the minimum trailing distance (I believe it is something like 200m) as a car behind a vehicle can provide an advantage.

But mind you, fairings aren't some exotic recumbent only feature - any bike can be faired ;)

Relatively poor visibility, in both the "seeing things"
I completely disagree. I naturally want to face forward and upwards rather than somewhat downwards towards the ground (this is comparing a road bike to a road recumbent two wheeler). One of the reasons a lot of people enjoy bent's is for this very reason - it's much easier to enjoy the world around you :)

"being seen" senses of the word,
People say this all the time... I disagree from an expirience point of view.
First, cars tend to swerve out of the way to miss turtles and other small debris. I've never seen a recumbent smaller than a turtle crossing a road. At the same time, cars claim to have never seen other cars when they get into a crash. You can't expect anyone driving a car to see anything regardless of what bike you're on.

From the aforementioned experience point of view... I'm currently living in San Francisco and ride my recumbent everywhere. I command much more attention while on my 'bent than when I'm using a loaner diamond frame. Cars get a lot closer to me when I'm on a diamond frame and they keep away when I'm on my 'bent. It's nice :D

In Orlando, FL - I ride on the road. Orlando is NOT a bike friendly city like San Francisco.... I had been riding on the road with the frame pictured below more than 6 months without issue on roads with a speed limit of 45 ;) I do try to avoid bike lanes, where possible, as they're poorly designed - road debris gets pushed in by cars. Normally, these small items are fine for cars, but potentially detrimental to bikes :/

Yes, I will admit that there is potential risk while riding in the door zone. Lucky for me, all of the accidents I've heard of are of people getting "doored" while riding a diamond frame bike... So no one can claim visibility in that respect - if the person doesn't look, it doesn't matter how big, tall, bright or otherwise you are ;) The point is, be predictable - I'm not saying don't take safety precautions - I'm saying the best safety precaution is how you ride, not what your ride or what you ride with.

Recumbents have a considerably lower profile
There's a different tool for every job. Your comment is not well informed ;) I ride a high racer recumbent - which is, in fact, a high profile 'bent. High racers, according to the manufacturers, have been popular due to their dimensions and wheel sets... But again, what good is this profile when the profile of a car is too small to prevent an accident?

Riding a bike for utilitarian reasons---as opposed to weekend recreational riding---demands somewhat different tests of practicality.
I totally agree - by the same token, understand that "recumbent" does not refer to a bike with similar geometry such as a diamond frame bike. A tri-bike has an overall similar geometry to a commuter. But both of those bikes have very different handling characteristics as they're different tools for different jobs. I don't ride a super low bike meant for racing.

The lesser ability to deliver gravity-assisted pedaling power can also impact the hauling of heavy loads
I again, disagree. If the recumbent bike has the same drive train as the non recumbent - I'm totally with you. But this isn't the case. Designers know that gravity isn't going to help - so we're geared as such. The breadth in gearing on my 'bent is huge enough that I've got an instructable on how to move house by bike - and I used my 'bent, fully loaded in San Francisco - a city not known for it's level terrain :)

As a side note - my intentions aren't argumentative. You've provided clear, thought out points that I semi-frequently hear at traffic lights while talking with other cyclists. Most of these fellow riders have never ridden a 'bent or have only tried and say it's "hard" :D I've been on 'bents for >4 years, in traffic an everything, and have no plans to stop :D I'll try to get helmet cam footage while riding in traffic for a space comparison :)

So I guess I should show a picture of my bike :D It's dual ETRO 559 wheels - so 26" equipment fits on it :) This isn't some obscure bike that isn't representative of 'bents - because no frame is representative of the recumbent community. This frame was commercially manufactured and a new version with similar specs is still sold today :)

Yes, I love my bike - it fits on bus bike mounts, I can bring it on the subway and while cruising downhill, I can put my feet up lazy boy style :)
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dang that looks comfortable... but i'm more of an offroad kinda bike rider. i prefer to stand up when i'm riding on trails. either way, thats pretty cool. I'd try it.
there are a few more drawbacks. Keep in mind, I'm not a 'bent hater here Jumping curbs, off road riding - much tougher with the recumbent. Not being able to pull a wheelie is a major disadvantage everywhere besides the paved bike trail. Bike racks on public transport - putting a 'bent on a bike rack on the metrobus is not allowed. This has more to do with the shape of the 'bent than anything else. So having a 'bent may restrict your commuting options.
trebuchet03 (author)  kill-a-watt7 years ago
Public transport is a good point - I never thought of that, but I don't have decent (easily used) public transport.

Curbs are also a good point - I make it my business not to jump curves on my normal bikes anyway :p But going up curves could be a problem - although, I was never able to get that stupid beach cruiser up any appreciable curb (I wouldn't expect it to either). I can see where that would be a benefit for some though :)

Pulling a wheelie -- yes, that too. The only time I pull up on my bike is for comfort reasons (unavoidable bumps), which isn't a problem on a 'bent with a proper seat :p But I ride almost exclusively on paved roads (and don't go up curbs anyway).

Off Road riding.... Well, there's plenty of video out there of people taking their purpose built 'bents off road :p
Video
invalid movie: www.youtube.com/watch?v=UGo5eeb0OBI


But the emphasis must be put on purpose built - I mean, I wouldn't expect my road bike (or even that beach cruiser) to perform very well off road :p In fact, I know explicitly that they don't perform well at all :p

So, revised drawbacks

*hill climbing ability for heavier 'bents
*no wheelies (or very hard to)
*going up curbs may be a problem
*potential public transportation issues (that could be a big issue for some)

+/- for off roading - I haven't done it myself (and don't do it normally), but it seems people do it without issue. I'll rank this with "balancing is harder" - it's not harder, just different :D
I'm an extremely pedestrian conscious bicycle rider. This comes from being a hiker first and foremost and my personal experience on many mixed use trails (summery: I don't mind the horses, but If I have to pick up after my pet, why don't they? -and- Well over 51% of bicyclist on the trails are either ignorant or outright hostile toward "sharing the ~~road~~ trail". Twice, for example, I've been hit by ignorant and careless bike riders that did not announce that they were overtaking me.) I'm also careful around autos. I know I have as much right to the road as them but well, Force equals Mass times Velocity squared. All this is a roundabout way of saying I hop curbs, a lot (please note that I stuck wheelies in there with hopping curbs. I'm not going to bash 'bents for not being able to pull a wheelie for the wheelie's sake) I break the law and ride on the sidewalk as a safety measure unless there is a pedestrian there. Being able to hop a curb is a safety maneuver that I don't want to be without. I ride a MTB in a mixed suburban neighborhood. That means that there are a variety of different terrain where I ride. There's a roadway nearby with a wide bike trail on the shoulder. However, to get to my house, I've got to turn on a road that has a very narrow two lane bridge. I can avoid this hotspot if I instead ride behind a shopping center, through a field, through a singletrack in the woods with a creek crossing, and through a townhouse neighborhood. I hop curbs a lot. All the metro busses in the greater DC area have bike racks. That's an advantage while being out and about while carless that I don't want to miss. In short, although I crave the comfortable seating of a 'bent, it's not suited for my style of riding. I do have a bunch of 20" bike parts around and I am lusting after a purpose built 'bent MTB for biking on the C&O towpath, which is technically off the pavement, but I'm betting that I won't ride that one nearly as much.
trebuchet03 (author)  kill-a-watt7 years ago
All this is a roundabout way of saying I hop curbs, a lot (please note that I stuck wheelies in there with hopping curbs.

Oh no! I didn't mean to imply that ;) One the guys I ride with does - but we call him the "new guy" because of the goofy stuff he does (and shouldn't do). The main reason I don't is because I'm riding on an old old steel lugged road bike, and really can't afford to damage my wheels. Really, I built a 'bent using dumpster materials :p

Twice, for example, I've been hit by ignorant and careless bike riders that did not announce that they were overtaking me

Yeah, I've been there too (just not on a trail) - it bothers me more when they're going the wrong way (I usually will yell something at them in cases like this).


In any case, my apologies if anything came off offensive to you - not my intent :)
Nothing came off as offensive, and that was never my intent either.
trebuchet03 (author)  trebuchet037 years ago


Sorry about the bad video link
Interesting., however these were pretty tame trails for a MTB. I didn't see a single log across the trail or a creek crossing with large rocks. Even the last scene had the 'bent going off the trail to avoid that hump, a minor violation of the "tread lightly" philosophy. MTBiking would not be what it is without the bunny-hop.
Oh, I didn't know that.

81mph on a bike?!?!? Taht iz fazt!
haha! i think so
yo bro i am lazy as a baptast sunday! even i can get exersize with your bike as i love to recumbent! hell i may even lay off my next heart attack for a year or two!
Shifrin7 years ago
This is a Great Instructable, I've always been wanting to both make and ride one of these, Hopefully now I can! Thanks -Alex
Woodenbikes7 years ago
Way to go Trebuchet3! Welcome to the www! (wonderful world of wood). These wood bikes are pretty addictive, in their funky clunky ways. It just makes you want to experiment more. A nice wood paneling fairing shell could greatly increase the danger factor on Widowmaker. In fact, now you've given me the idea to make the recumbent wood box coffincycle. Keep up the good work!
olderguy7 years ago
This sounds like a fun thing to do. It's going to be my 2nd project. Right after the bike trailer.
Leon Close7 years ago
Very nice, I have a similar but slightly more complicated project started myself. For the bottom (front?) bracket, would it not be better to chop the entire shell, complete with bearing cups, from a donor frame? I'm thinking there will be problems with bearing adjustment your way.
trebuchet03 (author)  Leon Close7 years ago
You could do that, but it's a lot of extra work ;) You'll have to carve out the wood to accept the whole assembly (believe me, that's not a whole lot of fun comparatively). I'll see if I can dig up pictures of an old project that did just that :)

The nice thing about using these cheap 1 piece cranks is that they hold themselves together with compression. The only adjustment is 1 threaded nut. The cups themselves are snuggly fit in the wood and I haven't seen them try to work their way out as of yet :p
Yeah I suppose it wouldn't really be practical to try and use a three piece bracket without the threaded shell. The press in cups certainly make it easy, and the wood should compress as much as it's going to after a few rides. A bit of epoxy would help too.
trebuchet03 (author)  Leon Close7 years ago
Woodenbikes.com mentions 3 piece cranks here. But it's not good news for wood application :p

As he said, keep low expectations and you'll get amazing results :D

I was just thinking of how to use the entire BB shell... If I were to do it that way (try again)... I would drill a semi circle into the top of the boom and place the shell inside. Then use U-bolts or something similar to hold it down. Even some good water proof epoxy (in case of rain). Just an idea :D
oops567 years ago
I know one thing i would not be wearing flip flops on a bike of any kind
trebuchet03 (author)  oops567 years ago
It's Florida, Flip Flops or Sandals in any weather :p
Visitor7 years ago
Brilliant work (again). Please list the problems you mentioned in last step with your fixes to them. I've seen many recumbents where the chain is routed through a PVC conduit tube. It bends quite nicely and can be used to move the lower chain away from the moving parts. That handlebar looks like it might work under the frame too. IMO that high chopper style bar looks funny. Is there any way to fasten it to the fork crown?
Visitor Visitor7 years ago
Oh, and I can't help thinking that if one extends the longer 2x4 all the way to the rear axle, one wouldn't need a complete steel frame at all. My wife doesn't allow any more bikes in the house but I think I could build this so that she doesn't realize what it is until it is too late...
trebuchet03 (author)  Visitor7 years ago
It starts getting complicated at that point -- you have to accommodate the rear axle and/or drop outs and then you'll have to hard mount the head tube -- but it is possible :) Check out the woodenbikes.com link :D

My wife doesn't allow any more bikes in the house but I think I could build this so that she doesn't realize what it is until it is too late...

Just say it's not a bike -- it's a 'bent :p
trebuchet03 (author)  Visitor7 years ago
Please list the problems you mentioned in last step with your fixes to them.

I modified the final step to make to more clear :) The numbered items are issues and tips to avoid problems later ;) Key problems: seat (my lack of a bottom seat), I need suitable handlebars, and a noisy idler ;)

That handlebar looks like it might work under the frame too. IMO that high chopper style bar looks funny. Is there any way to fasten it to the fork crown?

Those are actually cruiser handlebars :p But yes, it's not ideal. Under seat steering (USS) requires some extra equipment (tie rod and some sort of frame interface). If you're close enough (and have the physical space) to the fork, you can hard mount a USS handlebar - but that will be very uncomfortable if you're too far away :(
Lftndbt7 years ago
This makes me smile ;) Hardcore biker here... The guys at work bag me enough as it is for riding ( yet individually all have asked me how to get their calves looking like my guns by summer... ;P ) I always wanted to have one of these! Not sure if the cannondale will convert though....;) Bike's are sooo good... Nice Instructable!