Building a Barracuda lowracer recumbent bicycle (low racer HPV)
  Barracuda Frame
The ongoing saga of the creation, modification, and reincarnation of the 'Cuda lowracer 
    1999     2000     2001     2002     2003
By Warren Beauchamp
Len brought what he had completed so far  to the WISIL meeting, which was the main tubes, and the front boom. Here all all the tubes and parts layed out on the floor.
barracuda-frame1.jpg (6472 bytes)
barracuda-frame3.jpg (14137 bytes) 4/18/98
Len brought the almost completed Barracuda frame to the WISIL meeting. Looks nice. Here's a picture taken by Eric Van at the WISIL meeting. That's me holding the bike.
Len delivers the completed frame! Now the work begins again for me. I put on the wheels and inserted  the crank tube to see what it will look like. As you can see, it's very low. It's just shy of 3 inches (that's about 7.5cm to the English measurement impaired). I weighed the frame, and it's about 10lbs bare. Not exactly light...
barracuda-frame2.jpg (9108 bytes)

As a seat never materialized, I spent some time at Bill's making a slider bracket to attach the temporary seat to the frame  (I borrowed the seat from my wife's Tour Easy clone), and another slider bracket for the Jackshaft. The brackets are made from a 1" wide chunk of chrome moly tubing of a size that fits around the existing frame tube For instance if you have a 2" OD frame tube, you would want to make the bracket from a 2" ID tube. A long nut is brazed on both sides of the bracket tubing (180 degrees apart), and the whole thing is cut into two half circles. This leaves half the nut on one bracket, and half on the other. The nuts on one bracket half are drilled out so a bolt can slide through, the other side has the threads chased to remove flux and errant braze. Add some hex head bolts, and you have an amazingly strong clamp. We use them for practically everything...

Here's a photo of the jackshaft, without the derailleur needed to tension the front chain segment:

I rode it like this up and down the block, but the chain kept falling off. I later added the front derailleur (using parts from a rear derailleur) and have ridden many miles without incident.

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Here's a picture of the nearly competed bike (still without front derailleur):

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The 'Cuda now weighs 25lbs, and it's about 6 feet two inches long. Next I'll be finishing up a few details on the frame, and painting it. Hopefully by the time that is done, Len will have finished the parts needed for the seat that I designed for the bike. In the meantime, Garrie Hill has offered to sell me a carbon fiber seat for the bike, but it turned our to be too short for my long backside. We still may be able to work something out on the carbon fiber seat front...

Due to conflicting schedules (I had to paint my house), I now have less than two weeks to build a full fairing for the Barracuda.  This will be an experiment in efficient fairing building. Today I ordered a sheet of 80 mil Vivak (PETG) plastic for the nosecone, a sheet of 60 mil Vivak for the canopy, and two sheets of white Coroplast for the body. They will be in tomorrow, then it will be off to the WISIL skunkworks (Bill's Basement) for some fairing blowing. 

As of today I have painted the frame (primer black), worked the bugs out of the drivetrain and added a more permanent steering assembly. I'm still not sure if I will need to make a "remote steering" assembly to fit it in the fairing. It handles very nicely, and I can take my hands off the handlebars for a short time without crashing. barracuda-frame5.jpg (4435 bytes)

The derailleur position will become more permanent after I acquire or build a seat for the bike. As it needs to be finished (with fairing!) for the Northbrook 100 race on the 18th of July, I have decided to use this seat for now.

While working on the bike in preparation for the Northbrook 100, I discovered two things. The first was that the chain rubbed on the bottom of the seat when I sat in it. The second was that the handlebars were way too high to see over with a fairing on the bike.  This meant that I had to make a new seat, and fabricate the remote steering assembly before I could even begin to fit the fairing. For expediencies sake, I made the seat out of 3/8" plywood (with the mandatory lightening holes), and padded it with some closed-cell foam (a cheap sleeping bag pad). The remote steering required another trip or two to Bill's house to braze up the assembly. I also was able to find the time to blow the front nosecone for the fairing. Unfortunately, I was not able to get it mounted before the race, so I had to race the bike naked (the bike, not me). The bike performed well, (and I guess I must have as well) as I came away with 2nd in the 50 lap race, and 3rd in the sprint. It was a great event with 19 stock class participants. Since then I have completed the nosecone, and I am working on mounting it to the bike.

Here's a picture of me on the 'Cuda, being drafted by Sean Costin (who eventually won the race). The picture was taken by Eric Vann of Beezodog's place. barracuda-race.jpg (8807 bytes)

Here's a close up of the remote steering assembly:

The leftmost part, is a sawed off aluminum handlebar stem. It is tapped for a 1/4 hex head bolt, which passes through a rod end bearing. The rod end bearing is screwed into a telescoping aluminum tube, which attached to a rod end bearing on the right end. The right side rod end bearing is attached to the remote handlebars be another hex head bolt. The remote handlebar, and handlebar support tube are clamped onto the main tube. It works nicely. barracuda-frame6.jpg (18487 bytes)

After the Wisconsin HPV races of 8/29 and 8/30, which were on a very bumpy track, I discovered that I have to improve my chain management more, as the front chain keeps coming off.

I spent an afternoon at the WISIL Skunkworks in preparation for this years "Scarecrow festival ride" sponsored by the Bike Rack, a 'bent friendly bike store in St. Charles, IL. The mission was to finish the chain management, so that the front chain didn't keep bouncing off when the bike hit a sharp bump. I didn't want the chain to get sucked into the wheel again. One chain-suck induced crash is plenty for me. 

I modified a old front derailleur to create a permanent chain guide for the 62T chainring by brazing a bolt to the chain guide portion of the derailleur, and 86-ing the rest. The bolt was then attached to the frame by a slider clamp. I then made a bracket (attached to yet another slider clamp) to attach the "rear" derailleur to. This brought the fixed position derailleur much closer to the jackshaft gear, to eliminate any misalignment derailments. See how squared off the gear teeth are in this photo? That's so the chair can derail easier. That's not a good thing for an intermediary gear. I finally figured this out and used a Dremel tool to round the teeth off, and make them more like track cogs.   barracuda-frame7.jpg (8754 bytes)

The 30+ mile ride proved the chain management was now bump-proofed, as the course went up and down hills, over gravel bike trails, and across bumpy country roads. What still isn't perfect is the plywood seat. After the ride I had the killer recumbent-butt syndrome.

So, the next thing to work on is another seat. You can never have too many seats. This time I'll try a fiberglass over foam one.

Here we are, over one year since the start of this project, and I'm still tweaking. This picture shows the addition of the foam/fiberglass seat (which still needs some padding, but is already more comfortable than the plywood seat) and the front wheel disk. Interestingly, the seat did not save any weight, but does it feel much better.
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The custom super-long carbon fiber seat from Garrie Hill arrived! It is beautiful, and seems to be comfortable. It has been dubbed the "Potato chip" seat because it is so thin and wavy. I epoxied aluminum brackets to it using a mixture of   epoxy, cotton flox, and powdered graphite (to make it black). I changed the rear seat mounting point to the middle of the seat, as the shock transmitted through the seat stays in the previous arrangement was severe. I'm hoping the ride will be a little cushier... 
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I also added (but not painted) the rear wheel disk. The 'Cuda now weighs in at 31 pounds, not a lightweight, but acceptable.

As the first HPV race this year have a venue with a killer hill, I decided it was time to add another gear to the front chainring. As the chain comes quite close to to front fork, I can't just add other smaller front chainring inboard of the existing one. My options are:
1) Buy a "Mountain Drive" system - This is a neat system with internal planetary gears, which allows you to have a single front chainring, but still shift into a granny gear when needed. $500... Ouch.
2) Buy a Monoblade fork - The M5 low racer uses one of these (together with a disk or drum brake), and it looks very cool. $400... Ouch.
3) Make a Monoblade fork -  OK, I'll bite...

I ordered 1.5 feet of aero-tubing from Wicks aircraft supply, used a steerer tube from a MTB fork that my LBS was nice enough to give me, and went looking for a wheelchair hub. These are hard to find. I finally ended up ordering one from Phil Wood. The hub finally arrived and it is beautiful (It better be, it was expensive enough...). I de-spoked my existing hub, and rebuilt the wheel with the "Phil" hub. After much hacking, filing, welding, a number of trips to WISIL Skunkworks, and a threaded axle nut/tube specially made by Len Brunkalla, it is beginning to look like a fork.

I finished the monoblade fork, then went on a 60 mile ride with Ed Gin and company. The fork worked great, but due to the very recumbent position my head became extremely hard to hold up after 50 miles or so...

Started working on installing the secondary front chain ring, and front derailure, the mounting bracket requires another trip to Bill's house. 'Gotta get that torch!

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Took a short trip to Bill's house this week to make the front derailure bracket. It's a pretty long stretch between the smaller 48 tooth gear, and the 62 tooth main ring, but after some adjustment, it shifts pretty well. I finally have a "granny" gear! I took a couple detail shots of the fork. Click on the thumbnail pictures below for a bigger picture.

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I have been racing the Barracuda low racer with much success for three years at this point in time. The first year was unfaired, the second I was mostly faired, and this year I was fully faired. When cornering at speeds above 30MPH, I have been noticing some front wheel hop (wheel bounces on a minor imperfection, bike hops sideways a little). Any actual bumps in a corner makes it a lot worse, and it makes racing a real white knuckle experience. Because of this I have decided the bike needs a front suspension. After considering a bunch of options, including building a suspension fork, considering the M5 monoblade suspension fork, and seeing John Tetz's implementation of the Action-Tec head shock unit, I decided to go with the Action-Tec unit. This shock unit fits inside a 1 1/4" head tube, which means I will have to remove the steerer tube from my current fork, and add the mount for the Action-Tec unit, as well as removing the entire head tube to install the 1 1/4" head tube. As the front brake mounting bolt can no longer pierce the steerer tube, I investigated some hub brake options. It looks like the hub drum brakes are no longer an option, but Phil Wood makes a narrow profile monoblade hub with a disk brake mount. I'm currently not sure if I have clearance for it. The other option is making a new bracket to remount the existing caliper brake.

After being shown a picture of the Varna streamliners front brake, which mounts behind the head tube on a uniquely designed bracket, I decided to opt for simplicity and do the same. 

I ordered the Action-Tec shock unit, and Russ at Action-Tec sent me out a small tube, which their shock unit presses into.  I diligently hacked the steer tube off of the Barracuda's monoblade fork, bored out the old steer tube stub, and braised in the stub. It took two tries to get it straight. I sent the fork back to Action Tec, and then Russ had to replace the tube stub anyway as I had ovalized it slightly in the process of unbraising and rebraising it (Doh!). 

Back at the WISIL skunkworks, Bill and I worked diligently to remove the old 1" head tube, and replace it with the 1 1/4" head tube required for the new suspension unit. This was much easier than installing the tube stub in the fork, and required very little abusive language.

This week it all came together. The suspension unit looks good and everything looks straight.  I had Russ set the suspension unit to 1.5" travel, rather than the standard 2 3/8", as a road bike doesn't need that much travel, and I didn't have that much room. In the course of installing the new head tube I decided to vary the head tube angle slightly to get more clearance for the tire. I finished filing the unsightly bits of braise off the parts we made, and sprayed on the obligatory coating of flat black paint. Below are pictures of the Monoblade fork, with the Action-Tec suspension unit, and brake attached.

I had been looking for a lower Q-factor crank, with at least a  62 tooth chain ring, as well as a smaller chainring for sprint races and hills. I found the Ritchy Logic "Road" crank, which boasted a low Q (151mm with a 107mm BB), and had the 110mm chainring pattern of a regular MTB crank, which is needed for the 62 tooth chainrings I have been using. The only downside is that it costs over $100. A typical MTB crank has about a 170 mm Q-factor. Some older cranks are really narrow. I used one with a single chainring, and a 130mm Q-factor, during the last couple races this year. I really liked because it gave me more foot room in the streamliner. Another cool item for reducing the Q-factor, is the Phil Wood 96mm BB, also over $100.  Since I already spent entirely too much money on a fancy suspension fork this winter, I decided to ask Earl Russell if he could find something.  He found me a   Shimano 105sc road crank set (150mm Q-factor) with a Rans 63 tooth chainring. Cool.

Earl also came through with the oddball 1 1/4" headset needed for the the Action-Tec fork that I had been have problems obtaining.

Time to put it all together! Here is a shot of the 'Cuda with new suspension unit.

All the planning paid off, as the height of the front of the bike seems to be about right. I was concerned that the front of the bike would be higher after I had installed the suspension. Changing the head tube angle (It's 70 degrees now) gives me 4" of trail rather than 2", which should help the high speed handling. It also stretched out the wheelbase 2" to 46". As you can see in the picture below, the front end is a little higher than the rear end (the bottom tube should be parallel to the ground. When I'm sitting on the bike, and have the fairing on, the extra weight will level it out. Exactly how level remains to be seen. It may take some tweaking. 

barracuda-susp3.jpg (28417 bytes)
barracuda-susp4.jpg (13009 bytes) The bracket on the back of the bike in this picture is the rear fairing mount.

Now that the suspension mods are done, it's time to work on some new wheel disks. I wasn't happy with the flimsy ABS plastic ones I made before, as they were too flimsy.

Since the last update I have constructed a set of fiberglass wheel disks and modified the handlebars and shifters. I was using bolt on handlebar extensions to mount my GripShift shifters and brake levers, and decided I could lose a little weight by just braising the assembly together instead.

 I also shortened the brake levers for additional fairing clearance, and replaced the GripShift indexed shifters with non-indexed thumb shifters. I replaced the GripShift brand rear MTB derailleur with a short cage Shimano road derailleur for additional clearance. I was tired of having to constantly adjust the indexing of the GripShift setup. It was especially a pain when the bike is running in streamliner mode.

What can I possible do now to make the bike faster? I'm happy you asked! While this bike seems to be quite fast with dual 406mm wheels, the rolling resistance for a 700C wheel should be less. The intermediary drive also loses a little efficiency, mostly due to the chain having to wind it's way through the derailleur, but partly due to it's use of small cogs. A large diameter idler pulley is more efficient. This, combined with the large gear step up needed to run at streamliner speeds, has made me take a drastic step. 

Last weekend I cut off the back half of the 'Cuda. Yes, it was traumatic. I had constructed a jig from 2x4s, with a particle board base to ensure alignment of the new rear end. I learned my lesson while building the street 'Cuda. Always use a jig! It's very hard to make everything come out straight, even with a jig... Anyway, I welded on the new 2" diameter extension tube, at the approximate angle of the 'Cuda seat ( I used a 30 degree angle, should have used 35 degrees ). You can see the rear dropouts held in place in the rear of the jig.
I then constructed the rear space frame using 1/2" x .035" chrome moly tubing. It looks a little funky now with the giant monolithic tubing in front, and the thin tubes in back, but it should work well. Hopefully it will look better when I get it all together.

I will be using 4" diameter fiberglass impregnated nylon idlers under the seat instead of the intermediary gears, as I no longer need the gearing step-up. These idlers, available from McMaster Carr  - Nylon V Belt idler pulley, part #6234K3, are highly recommended as replacements for stock low racer idlers. The 5" one would be even better if you can fit it in your drivetrain. This will simplify the 'Cuda drivetrain greatly, and should be more efficient. 

Fortunately, even though the bike is quite a bit longer now (55" wheelbase), it still fits in the streamliner body (Yay!). I needed to do some surgery to fit the larger wheel, and will need to do some bodywork to re-fair the area around the wheel.

The landing gear will undergo a major rework as soon as the bike itself has the bugs worked out. The new telescoping landing gear will retract all the way inside the fairing, and will have a small trap door to cover the hole, as opposed to the large gash required for the previous pivoting version.

Also, I purchased a MAPP gas torch. It cost about $50 at Home Depot for the whole kit. This is a very small gas torch that uses an oxygen cylinder and a MAPP gas cylinder, both of which are the size of small propane tanks. It works pretty well, and can heat large tubes, BUT... The flame is not as concentrated as that of a conventional oxy-acetylene torch, and the oxygen tanks only last 15 to 20 minutes. I have gone through 4 oxygen tanks at about $7 each, so far on one tank of MAPP gas, just on this project. It's not a bad deal if you don't braise a lot, as a full oxy-acetylene torch setup costs about $300. After the initial investment, the oxy-acetylene torch setup is MUCH cheaper to run.

Next steps, mounting the chain idler, rear brake, and cables. Hopefully it will be rideable  by this weekend! 

After mounting the remaining bit and pieces, I took it for a nice weekend ride. While I can't tell if it it's faster yet, it did ride smoothly and much more quietly, and most importantly, nothing broke!  The 39T to 62T front derailleur shift works nicely, so I now have gears for hill climbs. 

I'm now in the process of building the new telescoping landing gear. Details at the bottom of the Landing Gear page.

I recently went on a fast 50 mile ride with lowracer yahoos Ed Gin, Gary Toy, and Larry Zenger. While the bike performed admirably, there was no noticeable increase in average speed over the same bike with a small rear wheel. This may have been due to the recent changes in temperatures which required me to wear a bunch more clothing. Top end speeds may have been higher. On a preliminary note, speed increases seem to be negligible when changing from a 406mm Conti GP to a 700C Vittoria tire, at unfaired speeds. In this experiment, aerodynamics still far overshadows the second order effects of rolling resistance and drive efficiency. Pictured below is the bike as tested, with the Garrie Hill carbon fiber wheel covers on the rear wheel. You can click on the picture for a bigger image.

The landing gear leg is now completed and it feels much more solid than the previous version. I'm now looking for a spring to pull it back up, and I'm starting construction of the assembly to lower the landing gear and lock it in place.

The landing gear has been completed and works nicely. I decided to go ultra simple and use a ring to pull the landing gear down, and just put the ring on a hook attached to the handlebars to keep it down, the pop the ring off the hook to allow the landing gear to go to the "up" position. 

While riding the 'Cuda low racer with Ed Gin & Co, I noticed that even going over the small curbs on our riding route caused the idler wheel chain retention device to scrape on the ground. When doing another test fit of the bike in the fairing, the idler wheel was so low that it was keeping the fairing from being mounted properly. 

Because of this I had to move the idler mounting bolt to a location that was higher and behind the seat.  As shown in the picture to the right, the bolt was move about 6 inches back, and about an inch up. I used the MAPP gas torch, which (except for it's hunger for oxygen tanks) has been working out quite well. 

After filing off the excess braise from the old mounting point under the lowest part of the seat, and remounting everything, it appears that this move works out much better, and the bike has a cleaner look with the bottom of the idler at the bottom of the frame. The bike now weighs 38lbs.

This design has worked well for me. In the past year I have:

* Gone on countless training rides.
* Won a very hilly 30 mile road race (lowracer in the streamliner body) called the Hometown Classic against 200 roadies (and a couple lowracers) in Wisconsin.
* Won a bunch of HPRA races. 
* Won 1st place overall in streamliner class at the HPV World Championships, in Brantford Ontario.
* Been timed at 58+ MPH at the WHPSC in Battle Mountain, Nevada.

This bike is finished. I can't do anything else to make it faster. The only thing that would make it faster would be to make it lighter, which of course means a whole new project.

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