@Ken I uploaded some more pictures. I hope it's more clear now. Mind the bulbs ;-) @Yann Some answers to your questions (I hope you don't mind putting it on the list): 1- No, I bought this seat as a curved rectangle. There's a nice dutch dealer who sells a lot of stuff for bike builders: http://www.elfiets.nl/main.php?sNewPage=Zittingen I bought the cheapest (most unfinished) one for about 35 euros. Sending those things is expensive though. Of course I could have built one myself, but for only 35 euros it would be quite a bit of work and testing to get the right shape. Not in the bike pictures is the seat material I put on top of this wooden seat. I made a seperate photo of this (blue stuff). The same kind a material (but black and less durable) is used by many recumbent manufactures (at least in NL). It costs 25 or more euros for a new one which is overpriced imo. A few years back I bought a square metre for 40 euros. Aparently this material is used as a filter for garden ponds and I was able to order it at a garden centre. I think that dealer I mentioned sells the same material (blue and black): http://www.elfiets.nl/main.php?sNewPage=Ligfietskussens 2- Yes, I used a CAD program. Usually I start with paper and pencil for a design (whatever it is), but using the 3D environment of a computer program gives me a lot of feedback. Whether things will actually fit is much easier to see and simulate. Like for example whether your chainline is not touching the frame. You can download my drawings now (cycle.free-creativity.com) You may use them any way you want, but I didn't plan to put them online and they might be unlcear and with errors. So please use them wisely :-) One error that I discovered: the attachment for the rear derailleur is a bit close to the gap where the wheel axle goes. This means that when I detach my front wheel I have to be a bit careful. 3- Yes, all was done at home. Well, I did have some 'supervision' of my dad, since I'm rather new with metal working. The welds are done with a TIG welder, so that's why the weld surface looks rather neat compared to other methods. 4- Although I didn't go the most environment friendliest way by using old bicycle parts, it was a rather cheap bike for me. Except for the seat, rod ends, chain, front tire and mudguards, all bike parts are second hand. Bike parts are the most expensive things of a bike, so I had a lot of savings there. Stainless steel was about 4 euros a kilogram when I bought it, so that's rather cheap compared to the rest. So to (roughly) sum up: seat 35, rod ends/caps 20, chain 15, tire 15, mudguards 15 which totals 100 euros which I had to spent to make this bike. I guess another 100 euros value for the stuff that I had laying around or bought second hand. To be honest: it's the machines to make the bike that I think are really the most expensive. Same here: I had never welded before, untill I wanted making bicycles. I started practising to weld on some steel bars, then stainless steel with smaller thickness. First things I made were for good use, but for which finish and strenght didn't mattered that much. My first real project was a bicycle trailer for big loads. Although it went rather well, 1mm tube thinkness was sometimes a problem in corners (I blew a hole in it with the torch). This python is my second 'real' project. Welding class sounds good! Wanted to do that myself (and safe me for my initial troubles), but I thought it was too expensive here. So I just gave it a go... Problem is: I never know wether I'm doing it he right way and whether my welds are strong enough. So far nothing cracked though. Good luck with your classes, a python would be a nice project indeed. There's no front derailleur on my python ;-p I thought 9 gears would be enough, especially since I knew it would take quite some time till I could cycle it in the 9th gear. And this bike is more like a prototype to see what can be done with center steering. My goal was to make a trike, but I didn't like the tadpole designs (hard to make a hook for the trailer and the long chainline is a pain in my eye). So I hope to attach the front of this Python to the back of a Jetrike. <- if anyone has tried this before, please let be know. Anyway, some more pictures of the BB attachment on my website. Initially I designed this differently (like you mentioned with bolts going through the tube), but then I saw the Jetrike design and thought that was a neat and simple solution. I was woried about the problem that the nuts and bolt would squeeze the 40x40x1.5mm tube too much and I would end up with a wrecked part. Though, I gave it a try and I think I was lucky because of a thing I hadn't foreseen: the square tube bends outwards and it comes in contact with the bolt. It can't bend any further because the bolt blocks it. See the last picture of the BB adjustment. Notice that the bolt is straight and the top part of the square tube is curved upwards. So I think it will hold, but time will tell. That was a lot of writing, but I hope it was of some use,. If you want more info, please ask. Patrick Hi Patrick, Thanks for posting a few pictures on your web site. I really like your design, it is very clean and looks fast and comfortable. I have a few questions for you: 1- Did you make the seat yourself? - If yes, can you tell me how you did it ? 2- Did you draw your python with some sort of engineering design software (ie: AutoCad) or did you improvise a drawing on a piece of paper ? - If you have an AutoCad drawing would you be willing to share it with the rest of us ? 3- Did you do the fabrication/welding yourself or did you get someone else to do it ? 4- What do you figure the cost of your python is right now ? The reason I'm asking all these questions is that I have been wanting to build a Python for over a year now and am slowly gathering ideas and designs for a project. I'm taking a welding class next week and I might be able to weld a frame for the course project. However, I don't have any CAD drawing to go by or anything close to a project plan and would like something to start with. One thing I noticed on your design is the way the front derailleur is attached to the frame using the two steel plates and the 4 bolts. Overtime you might find that the bolts will loosen up a bit and that the front derailleur might move forward as you push on the pedals. One quick solution to make sure this problem doesn't occur would be to secure both plates onto the frame by drilling 2 holes through the frame and plates and insert 2 threaded bolts. Thanks and have a great day. Yann