History

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Alan Robertson
Bikezilla was built in the 80s by the talented Alan Robertson, one of the founders of Circus Oz. He has pedal power on the brain; he's constructed all sorts of crazy machines, including a pedal-powered tram, and the pedal-powered First Fleet for the opening ceremony of the Sydney Olympics. It took him three weeks to construct Bikezilla; it went on in its first life to host a brass band. The bike band frequented parades and festivals, and went globe-trotting to such places as the US and Japan.

In the 90s, Bikezilla was put in mothballs, gradually rusting away in a chook shed in Bacchus Marsh until Shaun remembered its existence and tracked it down...

Resurrection

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Bikezilla, as recovered from storage... plenty of TLC required yet.

Initial overhaul included a set of slick tyres and a brake upgrade.

Further plans include custom suspension forks for the front, and standard suspension forks for the side fronts, in addition to modifying the frame to incorporate suspension on the middle rear. This isn't for comfort so much as to allow all the tyres to maintain contact, and to reduce the occasionally enormous loads on the wheels. Furthermore, multiple ratios are called for... Sturmey-Archer 3-speed hubs should provide enough range.

Beyond the basic mechanical upgrades, there are plenty of plans and possibilities for accessorising. The machine has already been festooned with bells and horns, and a rearview mirror was a worthy addition. A toolbox will be added, as will a stonking stereo/PA system; this will be the first element of what will be an extensive electrical system which may one day incorporate electric hub motors on the front wheels which will also provide regenerative braking. Fairy lights and air horns are on the cards, as is an esky.

But the most gob-smackingly awesome accessory destined for Bikezilla by far is POV-video LEDs for the wheels. Using the persistence of vision effect, spokes of 3-colour LEDs can be used to paint video in the air with the wheels. It has to be seen to be believed.


Upgrade

Drivetrain

Having cleaned up the beast and provided it with proper braking (replaced the old cantilevers with V-brakes), the next item on the agenda was to add some 3-speed action. It was necessary to switch the forward drivetrain to the right of the frame, and fabricate a double sprocket for the Sturmey-Archer hub. This was no mean feat, as brazing a couple of sprockets together is a fiddly job; the first effort wasn't up to scratch... here's the second attempt. Other mods required were cable hangers brazed onto the frame and narrowing of the stays for the narrower hub. At this point only the central drivetrain has been augmented; two more wheels incorporating Sturmey-Archers need to be built, and double sprockets fabricated.

Now that our behemoth is more capable of dealing with inclines, the next priority is to address a fundamental shortcoming: no way to deal with road camber short of tyre squash and frame flex. It's imperative that all three rear wheels remain in contact with the road, otherwise a great deal of effort can go to waste.

So, the solution is to add suspension to the middle wheel, allowing significantly greater travel upwards than downwards. The rear triangle from a cheap dual-suspension MTB was modified to suit, and the pivot point cut out of the front triangle.

The stays that hold the centre rear wheel obviously had to be removed, plus a couple of lateral cross-braces along with a tube that supported the upper central rider; it seemed a bit radical to go hacking away at the frame to such an extent with an angle grinder, but needs must... These three braces are to be replaced with altered versions serving the same purpose, but obviously avoiding the suspension.

The blanked-off rear bottom bracket seemed like the perfect spot for the pivot point (the chunky little tube that's yellow inside) so the side cover plates had to come off (they went onto the rear triangle's BB).

It was a tricky mission to trial-fit the pivot point, as once it was brazed in there'd be no turning back... Thankfully, it was possible to tack-braze it on well enough to withstand having the bearings pounded in, while allowing its angle to be tweaked once the rear triangle was fitted. Unfortunately, the bearings had to remain in situ while the pivot point was brazed on more permanently, otherwise it would have shifted. The bearings didn't survive such treatment too well, and will have to be replaced.

The rear triangle has shorter chainstays than those it replaces, so it locates the wheel only 10-15mm further back than it was originally. The lack of lateral bracing for the centre wheel won't be an issue since the outside wheels take the vast majority of lateral load.

The brace supporting the upper central rider has been relocated to make room for the spring (even though it looks like a coil-over damper, there is no damper inside). That's all the brazing done for the suspension, except the forward bracket for the spring, the lateral braces and the jockey wheel brackets to run the upper chain past the suspension pivot so it doesn't pull the tyre off the road. Chain tensioners also need to be made.

It seemed like a good idea to add some gussets to reinforce the relocated tube and pivot point... it's probably overkill, but a couple of hundred extra grams of steel won't make any difference. The bracket for the spring extends from the middle gusset. The suspension was trialled and tweaked, and seems like it'll do the trick.

There's a new type of BMX hub incorporating a little cassette, which only contains sealed bearings. The ratchet mechanism resides inside the hub, and hangs off the back of the cassette, so it was easy enough to cut off. This leaves us with a near-perfect idler to prevent chain tension affecting the suspension. A bracket is being fabricated for it to run the chains past the pivot point.

A couple of hours' work produced this bracket, which looked fine until it became apparent that it was completely in the way of the forward chain...
Aargh.


A couple more hours' work, and this complicated bit was born. It had to be trial-fitted like a dozen times, and was a right bastard... but now it's done. Chain tensioners still need to be fabricated.




Yet more gussetry adorns this part of the bike... these two were added
partly because they look really cool, but mainly to address some nagging paranoia about the possibility of occasional lateral loads on the middle wheel. It's all gussied up. Time to assemble it and sort out those chain tensioners...




All done. It's looking pretty sweet : )
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Electrics

A 250W 15" subwoofer bin has belts and hooks to hang off the frame; a 560W car amp is screwed onto its side and a small car battery sits on top. Mounts have been added to the frame to take two triangular cabinets .7m high, each with three full range coaxial speakers facing rearward with two more facing outwards in front, totalling 140W per channel.