Steve's 'Zeica'
The "Zeica" Recumbent Cycle
This bike has existed for less than 2 weeks but it's the fourth or fifth twisting - chain front wheel drive-recumbent cycle I've built. Plans of a similar previous effort are on the net in the "ihpva incoming" folder http://www.ihpva.org/incoming/2003fwd/ I have built and designed bikes as a hobby for about 18 years now and my own web page is at http://www.modularbikes.com.au/ This bike was designed to be a 26 / 20, that is 26" wheel at the front and a 20" at the back. Why these wheel sizes,I hear you say?
* It is hard to put suspension on the front wheel of this sort of bike because the chain forces would cause a normalsuspension to "bob" under pedalling forces. A big wheel can soak up bumps better than a small wheel so a big wheel at the front is good. Also a big front wheel makes it possible to use standard racing and mountainbike parts and produce a bike with high gear inches. My 20" drive wheel recumbent needs a 57T chain ring to getup to decent speeds whereas a 52T ring gets the 26" wheel going fast.
* I like to have a corflute tailbox on the back of my bikes, in fact I think my bikes are naked without them.They make the bike go faster, and they are a secure, safe, dry place to store stuff. With a seat high enoughfor me to be seen in traffic (600mm) and a 20" back wheel, the corflute tailbox fits neatly over the back wheelwith no cutout for the wheel necessary. The forks that hold the back wheel are compliant and bounce over bumpsto some extent so there is no need for a large back wheel for suspension reasons.
The "need" for the bike started about 6 weeks ago when another bike I'd built broke. I salvaged the parts I couldfrom the wreck and got designing and ringing metal suppliers and exhaust tube benders. Found a couple of suppliersnot far from home and headed out one Saturday morning to buy and then bend a piece of 50.8 x 1.2mm round mild steeltube which cost $25.00 for 6m. The gentleman at Midas Muffler shop in Preston refused all payment for the bending.
After drawing the plan for the bike I printed templates for cutting the holes in the the main tube and inserted thetwo fork tubes. (Programs for making the templates are on the internet at http://www.ihpva.org/incoming/tubemitresn.xls and undertubemitre.exe, under http://www.ihpva.org/tools/index.html) I find it best to make the holes undersize using a jigsaw and a drill,then file the last millimetre or so all around. Then the intersecting tubes were brazed in, and I put in across-brace to support the seat base, complete with screwthread braze - ons to anchor the seat. The parts from the previous bike were fitted and about 10 days ago I wentaround the block for the first time and 9 days ago rode about 40k with some friends without any real problems.
I'm very happy with the bike, it can be ridden no hands and pass many road-going cyclists. Plan to ride the bikein "Round the bay in a day" this year so the tweaking and improving and training on the bike will continue untilOctober at least. Gosh, it might even get a coat of paint by then!See you on the road somewhere!
Steve Nurse10/8/04
