This was written after the event. While the construction is still very fresh in my mind, I took few notes while building, so this is more of a story, than a history! Enjoy.
P.S. My HTML skills are rusty and I can't be bothered to spend much time on this right now, so I apologise in advance for any ugly formatting!
While I had heard of recumbents (And had seen some) before, I never really paid much attention to them until I started reading uk.rec.cycling. Certain advocates of the dark side (You know who you are!) sparked my interest and I decided that I'd like to have a go.
While trying to arrange a time to visit Ben @ Kinetics I was involved in a conversation about fixers which led to my agreeing to meet an Edinburgh-based chap called Eddie so that he could have a play on one. Unsure if he would bring his own bike, I nearly brought two with me, but decided against it at the last minute. As I rode to the meeting point, I passed a stationary recumbent rider and the idea that that might be Eddie flashed through my mind. "Nah" I thought, "He'd have told me if he was bringing a recumbent!". Just then I heard the click of an SPD and turned to see the recumbent rider riding towards me waving one hand.
The following two hours were spent riding up and down the meadows trying to work out how to balance, pedal, and steer around the idiots who kept jumping out at me and waving their arms. I was grinning for the remainder of the evening.
Having decided that I wanted one, I started investigating prices and discovered that I would have to start saving. I then stumbled across the Dutch Speed Bicycle. This seemed like the perfect low budget solution. I could source a donor bike from the Bike Station and the construction was apparently simple.
I downloaded the manual for the bike and read through it. When I started to look at what they were supplying, I realised that while it was very good value, I could build all of it if I could just learn to weld. Luckily there is an arc welder at work, and a person who was prepared to teach me. And so it began!
I'd love to claim that this was carefully planned out to the mm from the very start, but it'd be a lie. The basic design took shape on random scraps of paper for about a week until I started to draft it out properly in Autocad. This allowed me to work out what angle the frame would be at, and to get a feel for whether it was workable. From there I began construction.
The bike is basically the bastard offspring of the Dutch Speed Recumbent and the HPVelotechnic Streetmachine.
The first thing that I built was the seat. Principly because it was made of strips of metal and was thus easier to weld. I began by bending a length of the metal into a vaguely seat-like shape, which I tested by sitting on it. A less accurate design I can't imagine!
The spine of the seat incorporates a vague lumbar support over which the wooden back is then bent. The effect is very slight and is probably only marginally better than no support, but an improvement over a large support in the wrong place!
I then cut two pieces of thin plywood to make the base and the back. After an abortive attempt at painting one of these with Hammerite, I handed them to the joiner upstairs who sprayed them for me
I then cut and welded the tubing for the main frame. This consists of 25mm x 25mm x 2mm box section mild steel. The dropouts were made by cutting the tube so that a single side was left. Welding another piece of steel on top to double the thickness and then using an angle grinder to make the hole. Looking back on it, it's a miracle that the wheel fits at all, let alone points in the right direction!
I then welded two half sections of tube around the main boom, and used a milling machine to cut a 33mm hole for the headtube which was then welded in place.
At this point I stuck the fork in, mounted both wheels and marvelled at how the pile of metal had suddenly become a bike!
The next challenge was to mount the seat. This involved changing the mounting points on the "spine" to put them closer to the centre so that they'd line up with another length of tube welded vertically onto the frame. A similar system would be used at the rear, but using some homemade connecting rods to link the tube to the seat. The idea was that the rear post would also double as a mounting point for a home-made rack in the future. In the end time constraints meant that I used a standard rack. The post may still provide some utility as a point from which to mount a front rack (One day. When I get around to designing and building it!).
All that remained was to paint the frame and mount the components. I make no apologies for the newspaper content in the background. All I can say is that I didn't choose the wallpaper for the spraying room!
The project looked doomed at this point, because I was trying to get the headtube reamed and faced so that the headset would seat properly. The tube was reamed to 29.7mm and I wanted it at 30.0mm. I took it into EBC having had a discussion with one of their workshop techs about headtube reaming. I thought that he'd understood that I was wanting to use their tool (I was more than prepared to pay for it!). He thought that I was checking that they had one. The earliest that they could bookmy "bike" in for the work was two and half weeks away. I pottered off in search of anywhere that might have one. The only other bike shop in Edinburgh that keeps such a specialist tool was Andy Gilchrist Cycles who were currently experiencing a one week backlog. With dark clouds I took the frame back to work.
I was discussing it with another cycling colleague the following day when he suggested the age old maxim. "If it doesn't fit, use a bigger hammer!" I checked the facing (roughly) with a pair of verniers and then used a piece of wood and a big mallet to knock the races in. Problem solved! The bike swiftly went together then.
The following day I fitted the missing crank bolts and a rack, put two panniers on it, and took it for its first ride. Straight up Leith Walk, in the rain, to Waverly station. Onto a train down south and then from the local station to my parent's house. Much to the amazement of my colleagues who thought that I would take it for a test ride somewhere quiet first. My only concession to potential teething problems was to reduce the tension on the SPDs to minimum so I could guarantee unclipping. This resulted in an unhelpful unclip when I missed the clip with the second foot, pulled on the first to maintain speed and pulled the cleat straight out. It's not as easy to fumble with pedals on a recumbent. Especially heading up a hill in the rain!
Well. First impressions were good. There were no obvious stability problems. The boom didn't flex so much that I could see it while riding. The only problem was the seat. At this point it was still 3mm plywood on a metal spine. I can't begin to describe the discomfort that this was capable of providing!
Luckily my dad had a stash of bubble wrap in the garage which provided a makeshift cushion for the base. This saved my spine during the rides around the area, and during the ride home.
Further work on the bike resulted in the "After" picture at the top. It now has a leatherette covered, foam seat pad, and two firm back pads. Having ridden it in this configuration, I wonder at how I actually survived the original journey! The back pads will probably be supplimented by a third with many grooves cut in them to promote airflow, and then the whole affair covered with a piece of thin, soft foam. This will probably represent the maximum I can do the seat in this configuration.
Well. It's been fun, and I'm certainly planning to take a break from construction as soon as I get a chance, and start riding the damn thing! That hasn't stopped me from mentalling planning version 2. The expense of this bike has been in the components. The frame (Ignoring the cost implications of my time!) cost me about £20. I have several plans for a new version brewing in my head. All will involved building a proper (Kind of) jig so that I can better check frame alignment.
Plan 1: Same frame but remade with a jig to straighten it the small inaccuracies. I would also use the milling machine to make the dropouts, rather than clamping them together and weilding an angle-grinder!
Plan 2: Steal the bottom bracket suspension pivot idea, and add rear suspension. I have a rear sus spring which can be used and the design is pretty simple. However, this can wait until I've clocked up some decent mileage and thus have an idea of whether it is necessary at all. A suspended canvas seat would weigh less and be easier and quicker to make.
After that... who knows. Carbon fibre looks tempting, but I'd like to get my welding skills to a level where I could seriously consider playing with Aluminium first. I really don't have the setup (Or the money!) to start playing with Carbon Fibre just yet, and the engineering design will become far more serious then!
So all in... was it worth it? Hell yes! Just building it was fun and riding it is proving more so. LEJoG here I come!
- uk.rec.cycling - It's all your fault!
- Edinburgh Bicycle Cooperative - Supplier of all the parts.
- British Human Power Club - The little man on the back of "So You Want To Build An HPV" restored my faith in my design. I was beginning to worry that the seat would be too high.
- The Warehouse Sound Services - My employers, who have not complained about my out-of-hours bike construction despite everything, and who have all offered encouragement.