DIY Velomobile

Building a velomobile

Fairing Ideas

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My plans to work on this bike during the winter fell apart when I bought a pair of cross country skis, but I’m planning on putting some more work into this bike this season. The bike itself is running quite well now. I replaced the chain (linked two regular chains together), put a new cassette on the back wheel to make shifting a little smoother, and added the front brake. However, since the front wheel was a very cheap trailer wheel, the front brake isn’t as effective as I would like, so once this bike is capable of going fast, I will look into finding a better suited wheel.

I came across some fairing designs that will help me figure out how to make my fairing system work. The first is a kit that I could buy (though I won’t) that would instantly turn this bike into a velomobile. Unfortunately the cost is prohibitive at $800 for a convertible, or $1800 for a full system. This picture shows the convertible version, made of coroplast – the same material that most big political signs are made of.

The second design is a top-only fairing. This would be less effective since it covers a smaller area and not the rear, though easier to install and can be made in a way that unattaches easily as well.

This image was also a bit exciting, because it looks exactly like my bike’s frame! He used PVC pipe, cut in half to attach to the frame, with cable ties to hold it firmly in place. The T of the pipe is unthreaded, so this whole unit can unattach if it needs to be taken off (and hopefully stays snugly in place while riding!). I think I will borrow the cut PVC pipe idea unless something better comes up soon. Instead of a wooden dowel (not visible here but under the fairing) I will be using the tent poles I bought earlier to construct the frame.

Written by Andy

May 10, 2011 at 8:45 pm

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The Frame

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Still researching about what exactly the fairing will be made out of (more about that to come later) but whichever material is used, it will need a frame to hold it together. I hadn’t thought much about how to make the frame, but an idea came to me while at the Cornell gear swap this weekend. Tent poles are light aluminum, and there was a box of extra sets of poles for $3 that should be able to help make most of the frame.

Apparently there was a recalled part, so these were the rain fly crown pieces that no one else has a use for. I also found a few narrower pieces that may come in handy. I think with the right combination of curved and straight pieces, I can piece together most of the fairing’s frame from these parts.

Written by Andy

December 5, 2010 at 8:39 pm

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Thanksgiving rides

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While in Ohio for Thanksgiving, I brought the recumbent hoping to get out on some rides. It’s been up to 20mph winds and mostly 30-40F outside, but the last three days I got out for some short rides. On Friday, I did 12 miles on a short loop on low rolling hills. Saturday saw 24 miles on a bigger loop around a reservoir. Sunday was about 21 miles on a bike trail with a mix of pavement and crushed stone.

So far I haven’t seen any great speed advantages with this bike, since it is a bit slower on hills and weighs quite a bit. I thought it would do better in the wind, but the riding position is still a bit upright (which I hope to modify a little). I haven’t ridden much on upright bikes lately, so maybe my comparison abilities are just off anyway. The good part at least was that I didn’t need to touch any tools while I was out, so it looks like my repairs are holding well.

Written by Andy

November 28, 2010 at 5:02 pm

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November 23 – Steering and rear hub overhaul

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Tonight I fixed two big things: The steering system and the rear hub.

Steering -
This bike has underseat steering, which is a much more complicated way to make the front wheel turn, requiring 4 points of movement instead of the typical 1. The handlebar is attached under the seat, which pushes a bar (2 joints) which turns the headset. When I first looked at this bike, the front headset was stuck, and took a good forcing to unjam it. That was mostly from flat, rusty bearings in the headset which I replaced earlier. It was still pretty stiff though, so today I took the handlebars off. Instead of bearings, this is just a bolt going through a perpendicular shaft to the handlebars. I cleaned gunk off the bolt, put bike grease on, and tightened it back up. Some bike grease got worked into the joints on the steering bar as well. Now the front wheel actually turns just from tilting the bike! It’s smooth as butter. I’m scared that this is actually too smooth, but I probably just need to get used to this.

The rear hub -
This is a special rear hub. At first, I just wanted to take the gears off the wheel to see if I could clean them. While they do come off easily, they are unfortunately designed as a pack of 5 gears, and 2 individual ones. I may get a new set when the second round of fixing parts comes up, but it doesn’t look like my old commuter parts will work here.

I then proceeded to look at the wheel bearings. It appears that this wheel is not as old as the bike is, or at least the bearings are in way better shape. They appeared to have no wear, but the grease was black and gross so I cleaned those off and put new green grease on. Then the difficult part came. There are several little gears and bits in this 3 speed hub, and cleaning it out isn’t really possible. I cleaned what I could and doused it in more grease a few times until mostly new grease was showing. It took a while to figure out the order of putting the parts back on, but I think I got it right.

I went for a quick test ride in the parking lot of the office, and this work was a definite improvement! I can steer very easily and without it jumping around. It does tend to oversteer though, so I may consider a headset part that doesn’t allow that. Oversteering at speed would just throw me off the bike. While the rear hub work isn’t very apparent, it should reduce a little shifting hesitation and lengthen the life of those parts.

The grand finale tonight was trying to fit the bike in a Chevy Cobalt sedan. I had to open the 4 doors and the trunk, fold down the rear seats,  move and fold forward the front seats, and take off both wheels. Then I put the front end in the back seat, maneuver the bike’s seat over the car’s front seats, get the front end of the bike into the trunk, and then it all rested nicely. It would be much easier if the seat came off, but that would require unscrewing 9 bolts, some of which are still very stuck in place.

Written by Andy

November 23, 2010 at 11:48 pm

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November 20

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I made more adjustments to the derailleurs today, and I think it finally can reach every gear in the 3×7 setup! I tried to take it for a ride, and pretty quickly snapped a small piece of plastic that makes the rear hub shifting work. I took that shifter off, and used the old 3 speed grip shift attached to the seat, and that works. I just need to find a longer end cap to keep the grip part more firmly attached, but it more or less stays on as it is.

With one set of working brakes, it was finally time to take this out of the basement and go for a real ride. I headed towards the East Hill Rec Way, which is a mostly flat and straight path. I was sprinting the whole time because I was interested in seeing how fast it would go, and I think I was keeping up 30mph for a few minutes which I can’t do on an upright bike. At the end of the trail is a good decent, and even at those speeds I wasn’t yet in the hardest gear. Theoretically I should still be able to pedal up to a little over 40mph before it tops out. On my race bike, that point is closer to 30mph.

I also went up one of the steeper hills in Ithaca, about 18% grade, and was still able to keep moving fast enough to stay upright. Recumbents are much heavier than upright bikes, so I had heard that they don’t handle hills well. It wasn’t a usual hill for me, but it doesn’t seem like this should be much slower on big hills. My biggest fear before was that even if this bike could hit 40mph, it wouldn’t be able to climb hills. Apparently that won’t be a significant problem!

I rode about 10 miles total, but with lots of stops to check the parts and make small adjustments, so I don’t have any sort of average speed. I plan to take some more rides over the next few days to see what kind of speed I can keep up with my typical amount of effort.

The next big question is if this bike will fit in the car. Chevy Cobalt sedans aren’t very bike friendly, and it’s pretty long, so using the bike rack isn’t a great idea either. The seat is able to come off, but it’s not a quick nor easy process to do that.

Still to fix:

  • Add a front brake. (Housing is all cut and ready)
  • Need to disassemble the handlebar attachment and lube that up so turning is smoother
  • Find a way to cap the grip shift so it stays on
  • Install bar extensions for a better hand position when shifting/braking isn’t needed
  • Cut the cables and clamp the ends

I’ll try to get a picture up soon. The image on this site is the outline of this frame, for an idea of what it looks like.

Written by Andy

November 21, 2010 at 9:47 pm

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November 18

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Another productive night getting closer to my goal of making this bike in good working order. The main goal tonight was fixing the headset, which is what holds the front wheel on and allows the bike to turn. Since this had decided to stop cooperating, I took the front end off, and gathered up all of the old worn bearings.

The surfaces that are supposed to be smooth and allow bearings to move easily are quite pitted in some places, and bumping up with rust in others. Since this is just for steering, I’m not concerned with this being perfect (unlike for wheels moving at 40mph). I scraped off some rust bits, sanded down some others, put a hefty amount of grease in there, and set the new bearings in. One set each for top and bottom and then I screwed it all back together. That made a huge difference, and now steering is much easier and without the jumping and creaking noises.

I also cut new lengths of brake cable housing, and put those in place. While trying to attach the rear brake with scrap cable, it became clear that the current brakes aren’t going to work. The springs that normally hold them off the wheel’s rim are too rusted to do their job. I might scavenge some brake parts from other bikes for now, but will definitely be ordering some new ones.

Written by Andy

November 19, 2010 at 6:00 pm

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November 16

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Spent a long night working on the bike again. I ground a lot of rust from the braze-on mounts for cable housing, and used a drill bit to pull out the old ferrules that were stuck in place. A few metal ones were still jammed, and too hard to reach, so they are staying there forever. With new shifter cables and housing, things are running pretty smooth. I’m still having a hard time getting the front derailleur to shift among the 3 chainrings, so I might just use one less for the time being until I can figure this out. It seems like the listed allowable chainring size difference was not true.

After riding several tight circles in the basement, the front end started grinding hard. When I bought the bike, the headset was stuck in place, and took some forcing to get it moving again. I took it apart and found that one bearing casing was totally shattered to pieces, and most of the bearings had flat sides to them. The other bearing casing was okay, but the bearings are just plain old. For $5 I got replacement bearings. I just need to polish the headset surfaces, grease it all up, and put it back together to get the front wheel working again. Steering was pretty jerky before, and there are at least 3 other joints that could be contributing to that, but I think the bearings were the main problem.

I put the derailleur cable housing on, and the click shifters work very well now. I still haven’t figured out where exactly to put the extra shifter for the hub, but I think I can attach it to the frame of the seat. Hopefully that is enough out of the way of the handlebars (which are under the seat).

Written by Andy

November 18, 2010 at 6:00 pm

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