DIY Velomobile

Building a velomobile

A little more about the recumbent

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When I bought this bike, I was told that it was custom made, although now I’m noticing a label on the frame about the material. There’s no discernible name, so maybe it was just part of the frame scavenged to make the bike? It doesn’t matter much to me though.

It has an amazing amount of gear options. Between the 3 chainrings in front, 7 gears in the back, and a 3 speed internal rear hub shifter, it totals 63 speeds. That helps a lot with the range of gearing, but does mean that there is significant overlapping of available gear ratios. I have a feeling that either the front derailleur or rear hub won’t get used often, mostly just there for climbing up steep hills or flying down them. Some simple calculations indicate that even at 40mph, I should be able to still be applying force to the pedals. Most racing bikes top out around 30mph before the pedaling RPMs are just so fast that you can’t sustain it or it’s unsafe. On the other end, it should be possible to slowly roll uphill at 3mph also. At that speed, balance is the main concern, but it’s good to know the option exists.

The underseat steering is an odd feeling, but I can’t imagine riding with the higher up handlebars that some recumbents use. I think for hours of riding this would get really uncomfortable. The underseat steering also only requires a very light touch. I don’t need to rest any weight on those bars. I have to assume that underseat steering is also a bit faster, since it’s a lot more aerodynamic – and will also make building an aerodynamic bubble around the bike a lot easier.

I’ve taken apart the cloth seat, scrubbed it repeatedly until the green tinge was gone, and it’s dried out and back on the bike. The brake parts, front derailleur, and shifters have all been removed now too. My next plan while I’m waiting for the new parts to arrive is to scrub down the bike, hoping that some of the long term crud and some rust off.

Written by Andy

November 17, 2010 at 8:18 pm

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November 15th

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I got my box of parts from Niagara Cycles and got to work taking more pieces off the bike and fitting some new ones on.

  • The front wheel looks very cheap, but that’s what I expected. The rims don’t look like they were necessarily made for braking, but I think it will work just fine. This is a typical bike trailer wheel size, which wouldn’t normally need brakes. The rim tape, tire, and tube all went on fine and held pressure overnight.
  • The rear tire went on tight, and looks very fast for a mountain bike wheel. It’s 1.5″ wide, where most mtn bike tires are >2″
  • The shifters are bigger than I would have liked, especially since the handlebars have very little space. I moved the shifters in farther than they were before and that should work for now. I may try to wedge a few inches of PVC pipe in the end and wrap it all in handlebar tape to make a seamless longer handlebar. The cables attached easily and were shifting and just need some adjustment now.
  • The front derailleur was completely the wrong size and I have no idea how I measured that so poorly. At least it came with several shims, so it’s just fine. The chain is old, and isn’t too hard to remove a pin and put in back in, so I didn’t have to waste a quick link on this one yet.
  • The derailleur housing was the wrong size, so I need to order the right thing and then will worry about more of the cable adjustments.

I rode around in circles in the basement and already this bike seems much better with new tires and working derailleurs!

Written by Andy

November 16, 2010 at 9:57 pm

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First Order Placed

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After trying to remove many of the stiff and seized parts, I made a list of the parts to buy for the first round. Here’s what I ordered:

  • Shimano Acera 7-speed 3-chainring shifters with brake levers attached – $26
  • Shimano Alivio triple front derailleur – $16
  • Brake cable housing to replace all sections – $7 for 30 meters (?!)
  • Derailleur cable housing to replace all sections – $19 for 25ft
  • Cable tips to prevent fraying – $3
  • 20×1.75″ front wheel with new rim tape, tire and tube – $29
  • 26×1.5″ rear tire and rim tape – $18

Total expenses so far for bike and parts is now at about $250. These parts should make it run pretty well, although to make it really good a new back end (wheel, 9sp cassette, derailleur and chain) would do it for another $100 or so. The fairing assembly will be another larger expense, but that’s the latter stages.

Written by Andy

November 11, 2010 at 8:00 pm

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Evaluating the parts

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I bought this bike for just $100, which sounds like a great deal until the parts are looked at closely. Here’s what it’s got, and my plans:

  • Front fork was seized up, although after some forcing it is moving somewhat freely now
  • Front wheel has a very eroded aluminum hub that will need replacing
  • Front tire is cracked all over and needs replacing
  • Front brakes are stiff
  • Front derailleur is stuck, and only shifts down with a good kick
  • Chain is rusty and stiff, can probably be cleaned up but best to replace at some point
  • Seat is green from being left outside for a long time and needs a good wash
  • Rear gripshift falls off the handlebars and has broken plastic pieces so it doesn’t stay in gear; needs replacing
  • Front brake lever is stuck; will replace all cables and housing throughout
  • Hub shifter is stiff
  • Rear tire is old and cracked and will be replaced

So it will take a lot of work to make this in good working order. It does roll as is, and I rode 3 miles uphill the other day, but the brakes are useless currently, and shifting is pretty much nonexistent. Lots of work ahead of me…

Written by Andy

November 10, 2010 at 8:00 pm

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Let the journey begin!

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A velomobile is bicycle designed for speed and efficiency. While typical bikes surely are a very efficient way to get around on human power, a velomobile improves upon many of the aspects of cycling. They are low to the ground, and enclose the rider in an aerodynamic shell, enabling the rider up to 40% better efficiency than a typical upright racing bike. Though they are heavier and slower on hills, the overall speed makes up for this.

The problem is that commercially available velomobiles cost on the range of $5,000 to $10,000 and above if electric motors are included. So instead of spending that kind of money, I sprung at the opportunity to buy a long wheelbase (LWB) recumbent bicycle. It has a typical mountain bike size wheel in the back, and a small 20″ BMX wheel in the front. The frame is long, but low to the ground. The handlebars are under the hammock-like seat, and steer the front fork with a rod.

My goal is to transform this older recumbent into an enclosed speed machine, capable of riding 100 miles in half a day. I plan to spend many evenings over this winter to make that possible. Let the journey begin!

Written by Andy

November 9, 2010 at 8:00 pm

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