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AtomicZombie Extreme Machines Newsletter for November 26, 2014

making mudguards

A Zombie inspired Front Wheel Drive Lowracer

Homemade recumbent project in England


I'm sitting to write this a day after being paid a huge compliment. A friend upon seeing the bike for the first time exclaimed, "Wow!" and asked, "Isn't that what they call..." furiously searching for an appropriate descriptive, "...a C5?" And this, just a week after taking part in a discussion of that very machine on the Atomic Zombie Forum!

An insult to many quite possibly and whilst the lowracer may be one wheel, an electric motor and a sleek body shell short of a real Sinclair C5, having been a 9yr old fan of Sir Clive's creation back in 1984, to now have built my own recumbent cycle and have it even loosely compared...well, you get the picture.

I'd been toying with the possibility of owning a recumbent for a good chunk of the last decade after finding Velo Vision magazine. A chance online discovery of modern velomobiles led me to a Dutch company who sold the Alleweder velomobile in kit form along with plans for a 20/26 'bent.

Searching further online for bike plans led to Atomic Zombie's website and whilst none of the bikes at the time suited, the notion that people were building their own kept me interested. Every return visit to the site revealed a new model and when the Warrior was released, Atomic Zombie really had me hooked. Here was a serious bit of kit!

Being from the UK though, one concern I had with a tadpole trike was how it would cope with the ridiculous barriers the cycle paths have over here. The Netherlands we are not when it comes to bicycle infrastructure, so low racers started to look appealing as a compromise. A production machine getting good reviews at the time was the Raptobike which had front wheel drive, a feature that made sense on a layout that placed much of its weight over the front wheel and a similar bike available, the Zox, had a square tube frame.

I had purchased a set of six plans a while back and felt liberated by the instructions within that gave some really straightforward how-to's. Looking at the Zox and thinking laterally from the plans, for no reason other than that familiar square tubed frame, the Zombie inside my head said, "Aha, I can build that."

So, I bought some 40mm mild steel box section, did a fag packet sketch, printed out some of the angles on A4 to use as a measuring guide and set to work.

As Joseph Whitworth discovered, accuracy is everything in engineering. A low racer frame starts at the boom before curving its way around the front wheel under the rider’s derrière to end at the rear fork. Creating all those angles whilst keeping the frame following a straight line can only be done with some form of jig, something us home builders don't have the resources for.

As most Zombie builders will have discovered, a half decent bench vise will suffice as a jig for each joint as you can clamp two pieces of square tube together in perfect alignment. Whatever angle you have mitred into them, two flat sides of the tubes will always be in line with one another, and for the same reason the joint you make at one end of a length of tube will be parallel to the joint at the other.

That's how all the main tube angles on this frame were done - mig welded in a bench vise. The front and rear forks were set up and tacked together on a flat surface and once checked for accuracy, clamped tight in the bench vise to be fully welded without warping out of alignment.

Being front wheel drive meant that a conventional fork wouldn't be wide enough for a rear wheel hub to fit. After making a pigs ear out of trying to modify an old mountain bike fork, forum user Stormbird came to the rescue with a couple of plans he had for a Zox style bike along with a raft of photographs. Along with the AZ plans, this gave me the confidence to stop dithering about and just build some from scratch using the steerer from the scrap fork, some hefty rear dropouts off the donor frame and some rectangular tube.

With a completed frame and forks a critical point in the build process had been reached. Yes, now I had to spend some money. After failing to bend some plywood into the shape of a bucket seat without it going c-c-crack, I took the easier option of buying a fibreglass one from Ocean Cycle as used by several recumbent manufacturers. The next deep breath to take was in ordering a set of wheels.

Being a Dutch Bike rider I love Sturmey Archer drum brakes. They are weather resistant, almost maintenance free and just plain old nice to use so a custom wheel set was ordered from Practical Cycles with sturdy black rims, the 26" rear wheel having a 70mm front drum hub. For the driven 20" front wheel I specified a 70mm drum hub with screw on freewheel, as rumour has it the cassette version they offer is difficult to service.

Having the wheels custom built was an expense but worth every penny for those brakes. For this rider, nothing comes close to a good set of drums and as a bonus they look superb, too. Compared with buying new wheels with disc brakes, they are actually pretty good value as everything comes included except for your choice of brake levers. It’s been good to read of some support for them on the Forum with a Warrior builder choosing some for his build also. Anyway, with the fork fitted and the wheels bolted on, the pile of bits now looked like a bicycle and a pretty sleek one at that.

A long tandem stem was found (the sort that clamps the Stoker’s handlebars to the Pilot’s seat post), but as 1 1/8" steerer tubes are slightly smaller than the nearest diameter seat post, a solution was needed to give a closer fit. Thinking laterally again, a trip to our local builders warehouse yielded a straight copper pipe fitting that with just one cut down its length with a hacksaw made the perfect shim! A set of town bike handlebars and lever/shifters off an old mountain bike put some icing on the cake, and with what started as a short and shaky first ride led on to almost 100 miles of dry weather road testing during which I became confident enough to crack on with getting it finished.

Two old chromo plastic mudguards (fenders) were fitted, the front being trimmed for chain clearance and both of them being extended with mud flaps repurposed from the bottle of an Eco brand of washing up liquid! On the rear went a lightweight Pletscher rack. A 'bar end' rear view mirror was hacked to fit as a motorcycle mirror would, helping greatly in traffic as craning your neck around to look behind in the recumbent position is less than ideal.

A kickstand was lengthened and a bracket welded on for it below the seat base; its position near the front of the bike suiting the weight distribution. In fact it's so sturdy, as a party trick I can sit with both feet in the pedals, wobble to tip the bike fully upright and pedal away whilst flicking the stand up by hand. This cannot be done showing off after a beer though. Don't ask!

The only real learning curve has been in trying to increase the maximum speed I can ride it at without the handlebars wobbling, due more to nerves I think than any flaw. For the first few miles, 15 mph was where the shakes began. Whilst it runs out of gears above around 25 mph, it will freewheel downhill at over 30 mph now with no issues.

A visit to a BHPC meet at Darley Moor race circuit during the summer saw Stormbird and another spectator take a ride on it, both of whom did fine, Paul in particular getting the hang immediately and giving its handling the thumbs up. Slow speed handling is good meaning that hill starts present no problem, and up steep wet or steep loose surfaces I've found that the best way to avoid a loss of traction is to adopt a smooth pedal stroke.

So, has it been worth it? Yes, of course. The result is a perfectly sound recumbent low racer that looks good, rides good and is practical to boot. It's taken me shopping, on 30 mile rides out around the cycle paths and canals of Manchester, has provided interesting conversation with interested passers by and will hopefully take in a few nights of camping next year. The build process has been thoroughly enjoyable and whilst as a bicycle it will never replace the Dutch Bike in my life, I wouldn't hesitate to do it all again and at some point probably will!

This being a Dad project, both my young daughters haven't had the chance to get involved beyond offering their opinions along the way, changing gradually from, "What on Earth?" to proudly telling their mates, "Our Dad made that!" The process of building it has hopefully been a quiet inspiration to both of them who have seen a bicycle created from dust.

They are enthused enough to want us all to build a small boat together next year to use on the nearby narrow canal, as it'll be something they can be involved in from start to finish and get to use for themselves. For their future, I'm encouraged by the female contingent on the Forum where I can offer a certain prolific electric trike builder to them as proof that this home brewing lark isn't just for the fellas.

I have no problem recommending Atomic Zombie to anyone that asks about the bike as despite it being my own creation, Brad and Kat's superb plans provided the kick start and answered so many questions along the way, as did the wonderful members of the Atomiczombie online community.
making a headtube

welding a headtube

headtube welded to bike frame

frame taking shape

wheels installed

recumbent seat installed

nearly completed recumbent

finished bike painted

closeup of drivetrain

finished recumbent bike

Ian, 39, lives in the town of Hyde, near Manchester in the North West of England with his wife, two daughters and a mischievous Jack Russell. He works as a Maintenance Fitter on an airport plant and vehicles. More on Ian's project can be found in the builders forum.

AtomicZombie newsletters are packed with features and information for bicycle enthusiasts.

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