Right: Chopper Riding Urban Dwellers (CRUD) Dragster Here is the latest creation from CRUD. It is actually an overhaul from an earlier bike. The rear wing is adjustable with one of the gear-shift levers in front of the seat. enjoy, -Martin Leugers |
To promote wheelie action, the driver's position is directly over the rear wheel. The wheelie aspect is responsible for the wheelie bar/trigger jack at the rear. As seen in the original sketch, above, the structure was envisioned as being welded-up from metal. However, since the machine is inherently less efficient in its drive scheme, it has been decided to make the machine's structure primarily of carbon-fiber composite over foam. This will result in its weighing half as much as the metal version, with no loss of strength and stiffness. If that doesn't overcome the inefficiency of the drive, we'll probably re-think further. After all, that's the idea behind the technological evolution of drag machines- "If it works, keep it, if not, lose it." It should be noted at this point, that the use of carbon-fiber composite over foam is a logical next step for those wishing to advance from the basic classes in a hurry. Merely making a silhouette transfer of your favorite frame onto a slab of plastic foam, cutting out and smoothing the shape, working in metal "hard points" where needed, then covering the whole thing with carbon cloth and resin will result in machine as strong as the original one you like, but much lighter in frame weight. I imagine that it would take a while, but I can envision "Funny Bikes" becoming a popular drag class. That would be a near replica of a classic bike executed in super-light materials. Rendering a Schwinn Phantom replica in carbon fiber would be complicated if one were duplicating the tubular nature of its frame; but by only going for the silhouette of the bike, with a solid foam middle, it would have the feel of the original, and be fairly simple to execute. Perhaps a better term for machines of this class would be " Stock Silhouette Dragsters". As usual, though, the first person to build one, will have the honor of naming the class. In this case, John Youens will probably be the honoree, as he's already planning to build a machine of this nature. For further thinking on this topic, see our "Project Minotaur" piece in the BRK Archives. Below is John Youen's take on the "Pro Stock Modified" category, like Mike's MTB dragster, above. The frame filler panels in both Mike's and John's concepts are part of the preferred equippage for drag bikes, to be sure of tripping the photo-electric-tripped timing device of the IBRKA Dragstrip setup. And, we need hardly add, they're great for graphics. |
Jim Wilson: Flywheel Assisted Unlimited Recumbent Trike This one uses a flywheel which is integral with the rear wheel, with no clutching. At launch, the rear wheel is eased to the pavement- smoking that fat gumball on the rear. |
The yellow arrows indicate how the crude belt-friction clutch will work. Push down on the handlebar, and it pushes an idler into the return belt to tighten it up. This system will eliminate the need for a massive rear wheel, and allow for a graceful acceleration without wasted tire smoking and power loss. Although the "wind it up and drop it" system will indeed work, I am guessing more than half the useful power will be lost as tires spin. This system will even allow you to feather the power while still pedalling and in a race you could use the flywheel much like a nitro tank, wait till the other machine takes the lead, then blast it all at the end over the finish line. My machine will also be a bike, not a trike and will be made of 1/8 thick 1.25 square steel. Also, since the flywheel is so large (21"), I should be able to have fun with the bike on the streets. I will wind it up as I coast into a red light, then just magically "hover" without falling over due to the gyro forces of the flywheel, then let 'er rip to put all gas powered monsters to shame as I blast past them. For brakes, I will add the original friction belt that was on the exercise bike (flywheel has a track), and just have a lever. This will stop the flywheel very fast (snowmachine style braking) while it is engaged to the rear wheel. I also have a Shimano freehub on my flywheel. Well, hope some day we can put these things on a track! It will be a blast. Brad ------------------------------------------------------------------------------------------------------------------------- Brad has taken an extremely pragmatic approach to the subject. Yes, burning tires are inefficient; but that is one of the aspects of auto drags which are something the audience likes about the sport. So, the Wizard Bros approach plays up this aspect, along with wheelies, which are add visual excitement. |
Mike Watson: Pro-Stock Modified MTB We started out promoting the idea that basic modified drag machines should be based upon steel-framed 26"10-speed road bikes and 20" BMX bikes. These are the most common "trash bikes", therefore the most accessible basis bikes for most people. However, Mike reminded us that cheap MTBs are becoming extremely common as well, and frequently show up at yard sales, curbside trash, and thrift shops. This is probably because they are extremely uncomfortable to ride more than about 30 seconds, mostly due to the crappy axe-like saddles they come from the toy store with. As it happens, 30 seconds is about the length of time required to cover 300 feet. Jim, you're in luck I've already got a drag bike built, it's based on a 26 inch wheel mountain bike frame and fork, with 24 X 1 3/8 wheels , 28-spoke, with a Shimano 3-speed hub. The smaller wheels drop the frame an inch, and the back wheel is all the way back in the dropouts. This aids in keeping the front on the ground in first gear. I dug into the BMX race parts pile and pulled out a GT 30 inch-wide cruiser handlebar, and a set of Peregrine 185 mm tubular steel cranks. The gearing is 50 X 18. Mike |
As you may have noticed, BRK has been pushing Bicycle Drag Racing almost since the beginning. Drags are an important part of proposed IBRKA-sanctioned events. We like the concept, as it's an excellent way of getting youth involved in our activity. Many young people lack the patience and bankroll to get into serious kustomizing; but anybody can afford to get into drag-bike building, at least in the basic classes. And when racing is involved, a lack of patience is a virtue. After all, the idea is to get it over with quickly, innit? We plan to introduce bicycle drags at the next Abita Springs Meet, in June '04. To further this goal, we put out an invitation to the BRK "Brain Trust", soliciting ideas on the design of various class machines. The primary emphasis was on cheap and easy. Like other forms of drag racing, it should be possible to start out in the more basic classes, and if you like it, to advance into the more radical/complicated/expensive levels of the game. Herewith are some ideas on the subject, from some of the most bike-performance-savvy people we know. |
A Y ! S U N D A Y ! S U N D A Y ! S U N D A Y ! S U |
B R K ' S D E S I G N L A B ~ B I C Y C L E D R A G R A C I N G : A Y ! S U N D A Y ! S U N D A Y ! S U N D A Y ! S U |
As you may have noticed, BRK has been pushing Bicycle Drag Racing almost since the beginning. Drags are an important part of proposed IBRKA-sanctioned events. We like the concept, as it's an excellent way of getting youth involved in our activity. Many young people lack the patience and bankroll to get into serious kustomizing; but anybody can afford to get into drag-bike building, at least in the basic classes. And when racing is involved, a lack of patience is a virtue. After all, the idea is to get it over with quickly, innit? We plan to introduce bicycle drags at the next Abita Springs Meet, in June '04. To further this goal, we put out an invitation to the BRK "Brain Trust", soliciting ideas on the design of various class machines. The primary emphasis was on cheap and easy. Like other forms of drag racing, it should be possible to start out in the more basic classes, and if you like it, to advance into the more radical/complicated/expensive levels of the game. Herewith are some ideas on the subject, from some of the most bike-performance-savvy people we know. |
Mike Watson: Pro-Stock Modified MTB We started out promoting the idea that basic modified drag machines should be based upon steel-framed 26"10-speed road bikes and 20" BMX bikes. These are the most common "trash bikes", therefore the most accessible basis bikes for most people. However, Mike reminded us that cheap MTBs are becoming extremely common as well, and frequently show up at yard sales, curbside trash, and thrift shops. This is probably because they are extremely uncomfortable to ride more than about 30 seconds, mostly due to the crappy axe-like saddles they come from the toy store with. As it happens, 30 seconds is about the length of time required to cover 300 feet. Jim, you're in luck I've already got a drag bike built, it's based on a 26 inch wheel mountain bike frame and fork, with 24 X 1 3/8 wheels , 28-spoke, with a Shimano 3-speed hub. The smaller wheels drop the frame an inch, and the back wheel is all the way back in the dropouts. This aids in keeping the front on the ground in first gear. I dug into the BMX race parts pile and pulled out a GT 30 inch-wide cruiser handlebar, and a set of Peregrine 185 mm tubular steel cranks. The gearing is 50 X 18. Mike |
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Brad Graham: Flywheel-Assisted Unlimited Recumbent Brad chose the most exotic class we've proposed. We like the masses of torque available from flywheel energy storage, We also like it because the IHPVA doesn't allow it. |
The yellow arrows indicate how the crude belt-friction clutch will work. Push down on the handlebar, and it pushes an idler into the return belt to tighten it up. This system will eliminate the need for a massive rear wheel, and allow for a graceful acceleration without wasted tire smoking and power loss. Although the "wind it up and drop it" system will indeed work, I am guessing more than half the useful power will be lost as tires spin. This system will even allow you to feather the power while still pedalling and in a race you could use the flywheel much like a nitro tank, wait till the other machine takes the lead, then blast it all at the end over the finish line. My machine will also be a bike, not a trike and will be made of 1/8 thick 1.25 square steel. Also, since the flywheel is so large (21"), I should be able to have fun with the bike on the streets. I will wind it up as I coast into a red light, then just magically "hover" without falling over due to the gyro forces of the flywheel, then let 'er rip to put all gas powered monsters to shame as I blast past them. For brakes, I will add the original friction belt that was on the exercise bike (flywheel has a track), and just have a lever. This will stop the flywheel very fast (snowmachine style braking) while it is engaged to the rear wheel. I also have a Shimano freehub on my flywheel. Well, hope some day we can put these things on a track! It will be a blast. Brad ------------------------------------------------------------------------------------------------------------------------- Brad has taken an extremely pragmatic approach to the subject. Yes, burning tires are inefficient; but that is one of the aspects of auto drags which are something the audience likes about the sport. So, the Wizard Bros approach plays up this aspect, along with wheelies, which are add visual excitement. |
Jim Wilson: Flywheel Assisted Unlimited Recumbent Trike This one uses a flywheel which is integral with the rear wheel, with no clutching. At launch, the rear wheel is eased to the pavement- smoking that fat gumball on the rear. |
To promote wheelie action, the driver's position is directly over the rear wheel. The wheelie aspect is responsible for the wheelie bar/trigger jack at the rear. As seen in the original sketch, above, the structure was envisioned as being welded-up from metal. However, since the machine is inherently less efficient in its drive scheme, it has been decided to make the machine's structure primarily of carbon-fiber composite over foam. This will result in its weighing half as much as the metal version, with no loss of strength and stiffness. If that doesn't overcome the inefficiency of the drive, we'll probably re-think further. After all, that's the idea behind the technological evolution of drag machines- "If it works, keep it, if not, lose it." It should be noted at this point, that the use of carbon-fiber composite over foam is a logical next step for those wishing to advance from the basic classes in a hurry. Merely making a silhouette transfer of your favorite frame onto a slab of plastic foam, cutting out and smoothing the shape, working in metal "hard points" where needed, then covering the whole thing with carbon cloth and resin will result in machine as strong as the original one you like, but much lighter in frame weight. I imagine that it would take a while, but I can envision "Funny Bikes" becoming a popular drag class. That would be a near replica of a classic bike executed in super-light materials. Rendering a Schwinn Phantom replica in carbon fiber would be complicated if one were duplicating the tubular nature of its frame; but by only going for the silhouette of the bike, with a solid foam middle, it would have the feel of the original, and be fairly simple to execute. Perhaps a better term for machines of this class would be " Stock Silhouette Dragsters". As usual, though, the first person to build one, will have the honor of naming the class. In this case, John Youens will probably be the honoree, as he's already planning to build a machine of this nature. For further thinking on this topic, see our "Project Minotaur" piece in the BRK Archives. Below is John Youen's take on the "Pro Stock Modified" category, like Mike's MTB dragster, above. The frame filler panels in both Mike's and John's concepts are part of the preferred equippage for drag bikes, to be sure of tripping the photo-electric-tripped timing device of the IBRKA Dragstrip setup. And, we need hardly add, they're great for graphics. |
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John's designs make extensive use of foam- core board for these elements and the mostly-styling aspects of frame fairings. Foam-core is perfect for this usage; because it is simultaneously rigid, yet weighs almost nothing. It is easily worked with a sharp knife, and works well with most adhesives used with wood or paper. Used mostly for artwork mounting, it may be had from any art supply source for about $20 per 4' X 8' sheet of about 3/16" thickness. Solvents will dissolve the styro- foam core, (between white kraft paper face layers). However, solvent-based paints, Krylon, for example. may be used to finish it, if it is applied gradually in dusted layers, and finished with a light wet coat. |
John's designs follow the ground rules of the Pro-Stock Modified class very closely. They are based upon dead-stock frames fitted with any other bits, such as forks, wheels, drive-train, etc. which the builder wishes. Just because this class is meant to be simple and cheap doesn't mean they have to look that way, as John demonstrates superbly in these sketches. His "Launch Stabilizer", as seen at right, is an excellent idea, as well, but his "Trap Tricker". |
front-wheel fairing might be contested by other competitors, as it's designed to give advanced tripping of the trap's photo-electric circuit. We'll see what the judges say about it at the Abita Springs Drags, next year. Here are some tech comments by Mike Watson, regarding shifting methods for dragsters: "Three speeds are a cheap, easy shifting option. Another way to go might be Shimano cassette hub wheels with the pins ground off the cog clusters so the individual cogs can be selected in any combination of two or three and installed on the cassette to get the desired ratios. An indexed shifter can be used if any more than 2 speeds are used. Shimano index shift cog clusters use small regular jumps in cog teeth to get uniform up and down shifts with the indexed shifters; in a drag race you're only concerned with shifting up to higher ratios, so any jump in teeth numbers can be used, I would think, off hand anyways!" |
Now that you've seen some examples of the potential fun inherent in building and racing drag bikes, you may be tempted to start thinking about building some of your own. Please do; that's the idea behind this piece. We will continue to run articles on this subject, so we'd like to see your design concepts and photos of finished drag machines. Remember, you don't have to wait until some fancy IBRKA-sanctioned drag meet shows up in your neighborhood. You can build several of these bikes, since they're mostly cheap and easy to build, and you and your friends can race each other, anytime you want- but do try to avoid doing it in traffic. Have Fun! |
Right: Chopper Riding Urban Dwellers (CRUD) Dragster Here is the latest creation from CRUD. It is actually an overhaul from an earlier bike. The rear wing is adjustable with one of the gear-shift levers in front of the seat. enjoy, -Martin Leugers |
