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Dual 700C lowracer

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T O P I C R E V I E W
warren	Posted - 03/29/2012 : 17:11:25 Here's Larry's Magic Bike, a dual 650C lowracer. Rob Enlish's Hachi I have thought about a dual 700C lowracer for years, but never thought the bigger front wheel would make that much difference. Larry proves otherwise. Of course it also has to do with him laying flat, which I'm still not sure I could do. A bit of drawing time shows that my long legs can indeed straddle a 700C wheel, without even having pedal strike. This would be a FWD steel lowracer, with rolled curved 2" tubes. Not super light as I will probably need to use .049" wall tubing to get decent rigidity out of that long bend, but it should be well under 30 lbs. -Warren.
25 L A T E S T R E P L I E S (Newest First)
Speedbiker	Posted - 05/14/2013 : 19:22:44 Yeah, but you have to love working with steel :-)
warren	Posted - 05/14/2013 : 18:10:00 Yep Jeroen, I mounted the front brake on the back of the fork. Also mounted the seat temporarily with some sheet metal screws to make sure it is located properly before I braze some T-nuts into the frame. I just need to fab up some handlebars and it will be ready for a test ride. Ha, yes there is some major crank-wheel overlap. That will be a learning experience for me! I had some pipe dreams that this bike would be ready for the Waterford races, but I need a couple good days of building before it's ready to test ride so I don't think that is going to happen.
jeroen Schasfoort	Posted - 05/14/2013 : 13:40:09 Mount the brake on the rear of the fork, it improves the braking. Buiding a brakebooster for it is realy simple. It pivots on some canti like studs. Some bmx linear slick cables are a big improvement also. I suspect some chranc-wheel overlap?
warren	Posted - 05/12/2013 : 12:02:41 Added the return idler and the derailleur hanger. The hanger was modified from one Len Brunkalla made for the original Barracuda lowracer frame back in 1998 or so. It was chromo plate, 3/16" thick I think. Added chain and a Shimano 105 short cage derailleur I had in the parts bin. With the drivetrain nearly completed, it's time to to look at fastening the Seat, and then handlebars. Warren
Larry Lem	Posted - 05/12/2013 : 09:05:39 I make my own fork dropouts out of 1/4" 4130 plate as I found it stronger, easier, to locate the derailleur bolt hole. Larry Lem
warren	Posted - 05/12/2013 : 08:31:08 Installed headset. Wow was that tight, I hope I didn't trash it. Added the components and some chain so I could inspect the chainline and locate the return idler position. Full build page: http://www.recumbents.com/wisil/dual700/default.htm -Warren.
warren	Posted - 05/12/2013 : 05:09:21 The sugino chain ring had a standard 110 bolt pattern but it also had an internal splined pattern that I had to cut out so could use it as a standard 110 bolt pattern chainring.
Larry Lem	Posted - 05/11/2013 : 15:46:25 Why did you cut the center out of the 52t chainring? What kind of spider does a da Vinci crank use? Larry Lem
warren	Posted - 05/11/2013 : 13:36:58 I made good progress today. * Cut the hole for the bottom bracket and brazed it in place. * Cut the center out of an old Sugino 52T chain ring and mounted in up to my 160mm DaVinci cranks. * Took some of the rake out of the front fork with my trusty conduit bender. * Brazed on the power side idler bracket * Cut a big slot out of the Velokraft seat so it slides forward until I am intimate with the down tube. * Sat on the bike to check to see if I could actually reach the pedals (yes!). * Check to see if I will have heal clearance issues with the derailleur (no). -Warren.
warren	Posted - 05/09/2013 : 07:43:08 Thanks all. I ordered the Tektro R725s from ebay. $95 USD for the pair. It sounds like the people who are having braking issues are using these with MTB levers. You have to use the road levers with these for proper braking. -Warren.
alevand	Posted - 05/09/2013 : 05:03:13 It doesn't look like a lot of leverage on the Tektros, might be weak braking. Knees might hit too... theres a little more room on the back of the fork for some short linear pulls, braze on the bosses to the fork and use handles the have more pull.. http://www.ebay.com/itm/Tektro-926AL-Mini-Linear-Pull-Brake-Silver-BMX-Cyclocross-Road-Tandem-use-/140900324711 C: Tony Levand
PoiterH	Posted - 05/08/2013 : 22:57:12 Saw this aero fork and brake setup on a factory produced tryaffyleeet bike last week. Maybe there's a way to do away with the cable & noodle? Electric servo?
raptobike	Posted - 05/06/2013 : 22:35:12 Hi Warren, As Thomas said I do stock these in silver and black. They are nice brakes, but you have to use the corect handles with them. I typically use Shimano non series flat bar handles but recently found that SRAM also have the BL700 which is suited for straight bars and caliper brakes. Arnold.
LongJohn	Posted - 05/06/2013 : 22:07:41 Warren, You might want to contact Arnold of Raptobike, he can set you up with some sweet brakes: http://www.raptobike.nl/components/brakes-levers/brakes-calipers.html Thomas
warren	Posted - 05/06/2013 : 18:13:58 No wonder it so fast, you can't stop!
Larry Lem	Posted - 05/06/2013 : 17:55:11 I still have to modify my dual 650C to accept a front brake! I did not plan ahead for that... Larry Lem
warren	Posted - 05/06/2013 : 15:34:24 I did a little research today to figure out what to use for brake calipers. I need something low profile as the front brake does not have a lot of clearance to the frame tube. The Tektro R725 looks perfect. The only problem is that this is an OEM only brake, so it is hard to find.
Speedbiker	Posted - 05/04/2013 : 21:36:39 Sweeet.
warren	Posted - 05/04/2013 : 19:15:04 Yeah that is an ancient shop mate, but very useful. I had a productive day today. The front fork was widened using a conduit bender. The rear drive wheel fits into the front fork nicely now. Before cutting the head tube hole, a lot of time was spent measuring and eyeballing frame while mounted in the drill press. Here's the head tube temporarily mounted in the frame for me to eyeball it. I jigged up the frame on my frame jig and then brazed in the head tube. It looks like I may need to take a little of the rake out of the fork. I have a bottom bracket shell, bottom bracket, and some chain on order. I did not order any fancy parts, as this will not be a lightweight bike. I am hoping it will be under 30 lbs. -Warren.
Speedbiker	Posted - 05/02/2013 : 07:36:57 Hurry up and get it going so I'll know if I want to build one. Every man should own a Shopmate :-)
warren	Posted - 05/01/2013 : 18:52:04 I jigged up the bike and brazed the bent tube to the bottom tubes. It looks pretty good. This picture shows it with the seat resting on the bottom tubes and the reference rear wheel. The seat will slide forward a couple inches when I notch it to fit into the bent tube. -Warren.
alevand	Posted - 04/26/2013 : 14:52:13 A wire brush wheel on the grinder works, gets the tube nice and shiny. There is oil on the tube also, put on to prevent rust. C: Tony Levand
Speedbiker	Posted - 04/26/2013 : 07:57:11 Oren, you might want to the review the many successful bikes and streamliners Warren has brazed in the past 15+ years......
pupush	Posted - 04/25/2013 : 22:07:33 You may not care, but you might get better joints if you grind the oxide off your 4130 before you braze it. Keep up the progress. I am building a bike too. It looks like you might finish before me tho. made in Africa
warren	Posted - 04/24/2013 : 18:35:01 I cut the fishmouth into the bottom tubes this evening with a 2" hole saw in my drill press. I had to do it twice as the first time it was 10 degrees off. Measure twice and cut once and all that jive. It's pretty close now and I will use a hand file or the grinder to finish it up once I get the whole frame jigged up and ready to braze. Every time I build a bike I rediscover how many different ways there are to mess up. Good thing I am not a perfectionist. -Warren.

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