Saturday, February 19, 2011

Giant CT 102 to LWB Mid Racer Conversion

Giant CT 102 to LWB Mid Racer Conversion
by Bevin Chu
Taipei, China
February 20, 2011

Giant CT 102 Urban Commuter Bike

Three years ago I bought a Giant CT 102 Urban Commuter Bike. Now that I am forsaking upright bikes for recumbent bikes, I am seriously considering converting it to a DIY LWB (Long Wheelbase) Mid Racer.

Doing so would put the seat height dramatically lower than it is now, making the bike far safer in the event of a spill.

If I do go ahead, I will convert it to something similar to the following DIY LWB Mid Racers.

Recumbent Share Archive

Recycled Recumbents

Atomic Zombies Extreme Machines

Bill Meacham's Aluminum Recumbent, Scottsdale, Arizona, USA

Louis's Homebuilt Recumbent, Toronto, Ontario, Canada

Brian Bolton's Yellow LWB, Canada

Rob Szymanski's Recycle, USA

Steve's Tourmaster, USA

Joey Wallace's Black Widow, USA

Larry's Yellow Bent, Canada

Dan Peterson's Green Machine, USA

The above DIY LWB Mid Racer Recumbents are variations on the DIY Atomic Zombie TourMaster, shown below.

Atomic Zombie DIY TourMaster LWB Mid Racer, Three Views

The Atomic Zombie TourMaster is a variation on the Easy Racers Gold Rush of 1986, which won the DuPont Prize and set a world speed record as the first bicycle to exceed 65 mph.

Easy Racers Gold Rush LWB Mid Racer

The Easy Racers Gold Rush in turn, is a variation on the Jarvis Bicycle of 1902.

Jarvis Bicycle of 1902, possibly the first LWB Mid Racer Recumbent

As the saying goes, "There is nothing new under the sun."

Performer Low Racer COMP Limited Edition

Performer Low Racer COMP Limited Edition
by Bevin Chu
Taipei, China
February 19, 2011

Performer has just introduced a new model, the Performer Low Racer COMP Limited Edition

The company website provides three photos of the bike, but no data.

The photos indicate that it has disc brakes instead of calipers, and a different wheelset than the Low Racer Caliper. The front tire in particular, appears much wider than the 20x1 tire on the Low Racer Caliper.

Update as of March 10, 2011, by company representative George:
Low Racer COMP Limited Edition
alloy frame with alloy fork (carbon fork not strong enough for disc brakes) / SRAM Attack shifter / Shimano XT rear derailleur / Truvativ Elita 52/39/30 crank 170 mm integrated / 11-34 cogset / sealed bearing wheelset / Avid BB5 disc brakes / Kenda K193 20x1.25 (32-406) 100 psi front / Kenda K193 26x1.25 (32-559) 100 psi rear / 1060 gm FRP seat standard / 620 gm CF seat optional 6000 NT
MSRP 42,500 NTD 

It also has a slick red, white, and black color scheme, strikingly similar to that on the Giant Rapid 3 Sport Bike, rather than the monochrome color scheme of the Low Racer Caliper.

Giant Rapid 3 Sport Bike Color Scheme

Monday, February 14, 2011

Recumbent Bikes vs. Trikes

Recumbent Bikes vs. Trikes
by Bevin Chu
Taipei, China
February 5, 2011

Bikes vs. Trikes

I recently decided to switch from uprights to recumbents. My first choice for a recumbent was a SWB low racer.

Upright Bike, Diamond Frame (DF) Configuration, possibly a Felt

In a previous article I outlined my reasons for choosing a SWB low racer. The primary reason of course, was seating height. On a SWB low racer, one sits only 36 cm or so off the ground, depending on the make and model one is looking at.

Recumbent Bike, SWB Configuration, Performer Low Racer Caliper

But after I posted that article, a couple of experienced bent riders suggested that rather than switch from upright bikes to recumbent bikes, I should consider making an even more radical switch, from upright bikes to recumbent trikes.

Recumbent Trike, Tadpole Configuration, Performer JC-70 CM Sports Trike

They suggested that although my injuries might be milder falling from a recumbent bike than from an upright bike, that I should avoid injuries altogether, by switching directly to recumbent trikes.

They may have a point.

Geometry 101a

As anyone who ever took a basic geometry course in high school knows, two points determine a line, and three points determine a plane.

Two points determine a line

Three points determine a plane

What does this have to do with cycling safety?

Why everything.

Bikes: Two Point Support

The reason bikes fall over, is that they are supported at only two points, the front and rear wheel contact patches. Therefore if either of the two contact patches experiences a sudden loss of traction, the bike falls sideways and unceremoniously dumps its rider on the ground.

Please note that I am addressing only falls resulting from a loss of tire traction on the pavement. In a lifetime of bike riding I have never fallen because I "lost my balance." Therefore that is not an issue for me.

As I pointed out in great length in my previous article, "From Wedgies to Bents," a bike rider's injuries will be far greater falling from a "conventional" upright bike, than from an "unconventional" recumbent bike.

This is especially true if the upright bike rider is taller than average in height, and must set his seat at a considerable height above the ground for proper leg extension. My own DF seat height must be set a full meter above the ground. Had I been riding a SWB low racer during my recent spills, my injuries would have been trivial by comparison.

This was true when I wrote it yesterday, and it is just as true today.

Trikes: Three Point Support

But what if one could avoid falling altogether? What if instead of merely minimizing one's injuries from a fall, one could eliminate injuries altogether, by not falling in the first place?

How would one go about avoiding falls completely?

The only way to do so, would be to switch from bikes to trikes, rather than from bikes to bikes.

As noted earlier, the reason bikes fall over, is that bikes are supported at only two points, the front and rear tire patches. Therefore if traction is suddenly lost at either of these two contact points, the bike falls sideways and dumps the rider unceremoniously on the ground.

This can never happen on a trike. The reason a trike can never fall over, is that trikes are supported at three points, at all three front and rear tire patches. Therefore if traction is suddenly lost any of these three contact points, a trike will not fall sideways. The trike may skid sideways, but it will remain upright.

Trikes: Rollovers are Possible

The only time a trike will not remain upright, is when it changes direction so abruptly that it "trips" sideways on one of its wheels and rolls over. A trike cannot fall over, but it can trip over. The bad news is that this is possible.

The good news is that even when it does happen, the recumbent triker is still better off than the upright biker.

The recumbent triker falls from a seat only 23 cm or so above the ground.

The upright biker, on the other hand, falls from a seat a 100 cm above the ground. What's worse, the upright biker's shoulders and head are situated another 50 cm above the seat, i.e., a whopping 150 cm above the ground.

The difference between falling 23 cm and falling 150 cm may mean all the difference in the world.

Convenience Issues

Another consideration is convenience. Unfortunately a tadpole trike would probably be less convenient than a SWB low racer bike.

I live several stories up in a multistory condo. I'm not sure how convenient it would be to schlep a tadpole trike up and down a cramped elevator. I suppose I could tilt it up vertically on its single rear wheel, while pressing the two front wheels against the rear wall of the elevator.

This maneuver would probably be easier with a SWB low racer bike than with a tadpole trike. A SWB low racer bike is narrower and lighter. It could probably be tilted up vertically on its rear wheel more easily than a wider and heavier tadpole trike.

It might even be easier with a delta trike. A delta trike has two rear wheels. Tilting a delta trike up vertically on its two rear wheels, while pressing the single front wheel against the rear wall of the elevator would probably be easier.

A narrow SWB low racer bike would probably be easier to ride through narrow alleys crowded with pedestrians than either a tadpole or delta trike. I would be less likely to find myself backed up in traffic on a SWB low racer bike, than on either a tadpole or delta trike.

Further investigation is needed.

Where Does that Leave Me?

So where does that leave me?

Basically it leaves me at "Let's wait and see."

I am still recovering from the soft tissue trauma to my left knee. I am still giving the suspected fracture in my left scapula time to heal. Several months of physical therapy are still required. I have plenty of time to mull over my next step regarding "human powered vehicles."

My decision to cease riding "conventional" DF bikes has already been made. That decision is firm. My days of DF riding are over.

My decision to begin riding "unconventional" recumbents has also been made. That decision is also firm. My days of recumbent riding are about to begin.

The only question that remains now, is "Recumbent bikes, or recumbent trikes?"

Performer Low Racer Caliper, a SWB low racer

Performer JC-70 CM, a tadpole sports trike
Similar model, reviewed by Utah Trikes

Perhaps one of each?

Wednesday, February 9, 2011

The Most Ingenious DIY Bike I've Ever Seen

Microbent CLWB Recumbent, by Fred Fincher, USA

The Most Ingenious DIY Bike I've Ever Seen
by Bevin Chu
Taipei, China
February 10, 2011

Lately I've been surfing the web for DIY bike designs.

I have a 26" diamond frame urban commuter that I would like to convert into a LWB mid racer recumbent, along the lines of the Easy Racers Javelin or Rans X-stream 26.

But as I surfed the web, I stumbled across the above compact long wheelbase (CLWB) recumbent, converted from a diamond frame child's bike.

It has relatively little to do with my own DIY conversion requirements. But it is perhaps the most ingenious DIY conversion I've ever seen, and therefore useful as a source of inspiration.

What makes this particular DIY conversion so ingenious?

1. This DIY conversion makes full use of the existing bike design. Rather than laboriously fabricate new parts in a machine shop, it makes full use of every part already on the bike.

2. The crank assembly, for example, is merely a section of EMT, welded to the head tube. It extends forward along the axis of the top tube, just far enough to accommodate the rider's legs.

3. The seat bottom rests directly on the top tube, and is the exact same length as the top tube. The seat back begins exactly where the top tube and seat tube meet. The seat back supporting struts attach to the existing rear luggage rack attachment points. The seat back, seat stays, and seat back supporting struts form a perfect triangle. 

4. The USS (under seat steering) solution is perhaps the most ingenious feature of all. The builder simply welded two pieces of EMT onto the front fork, creating handlebars for direct steering. Because the DIY conversion uses a child's bike that is short in overall length, the handlebars fall directly below the rider's hands. This eliminates the need for any complex steering mechanism. No muss, no fuss. 

5. The DIY conversion requires only a single donor bike. No need to accumulate two or even more donor bikes before beginning the conversion process. Everything on the single donor bike is used. Nothing is wasted.

6. Because the DIY conversion uses a child's bike, the completed bike is low to the ground. This makes it safe in the event of a spill. The rider sits a mere foot or so above the ground.

Monday, February 7, 2011

Recumbent Highs and Lows

Barbara Buatois and her Performer Low Racer, at the Finish Line for the 2010 Race Across AMerica (RAAM) in Annapolis, MD

Recumbent Highs and Lows
by Bevin Chu
Taipei, Republic of China
February 5, 2011

I recently penned an article on recumbent bicycles, entitled "From Wedgies to Bents." In it I explained why I was abandoning traditional diamond frame bicycles, and moving to recumbents.

In this article, entitled "Recumbent Highs and Lows," I share my personal views on the relative merits of high racers, mid racers, and low racers; and explain why the SWB low racer is the recumbent of choice for me.

Recumbents are commonly classified according to two criteria.

The first is bicycle length. Recumbents are classified as either short wheelbase (SWB) or long wheelbase (LWB).

The second is bicycle height. Recumbents are classified as either high racer, mid racer, or low racer.

In theory, 2 x 3 = 6 configurations are possible. In practice, only three configurations have gained commercial appeal.

Those three are:

SWB high racers such as the Bachetta Corsa
LWB mid racers such as the Rans X-stream
SWB low racers such as the Optima Baron

SWB High Racers

Bachetta Corsa, SWB high racer 700C/700C, seat height 26.25" (67 cm)

The frame of the SWB high racer is simplicity itself. It is a perfectly straight tube. One can hardly get any simpler than that. As a result, the SWB high racer is as light as it can possibly be. The chainline is also as straight as it can possibly be. It is any wonder SWB high racers such as the Bachetta and Carbent have so may devotees?

Alas, they are not my cup of tea. Why? Because I have no desire to fall a full 67 cm before hitting the concrete pavement below.

LWB Mid Racers
Rans X-stream 26, LWB mid racer 559/559, seat height 20.5-21" (52-53 cm)

Next to the SWB low racer, the LWB mid racer is my favorite bicycle configuration. The LWB mid racer positions the rider's buttocks close to the ground, but by keeping his back relatively straight, positions his head reasonably high off the ground, providing him with an excellent view of the road around him.

I would buy a Rans X-stream 26 in a flash, if only it would fit into my condo elevator. The biggest drawback of the LWB mid racer is its sheer size. LWB mid racers are 8 feet long behemoths! If one wants a LWB mid racer, one really needs to live on the ground floor or have a garage.

SWB Low Racers

Optima Baron, SWB low racer 20"/26", seat height 13.5" (34 cm)

For me, the SWB low racer is the most desirable of all bike configurations.

The biggest obstacle to sustained speed on a bicycle is air resistance. The SWB low racer configuration minimizes air resistance. That makes the SWB low racer the fastest of all bike configurations, bar none. For sheer adrenaline pumping speed, nothing else comes close. Not just downhill, but even on flats or gentle rollers. Except when climbing, the SWB low racer simply leaves other bikes in the dust.

But for me blinding speed is merely icing on the cake. Some SWB low racer owners barrel down steep mountain roads at speeds approaching 100 kph. I have no intention of doing anything so reckless.

For me, the main attraction of the SWB low racer is not maximum speed, but maximum safety, specifically during a fall.

As I noted in "From Wedgies to Bents," as long as one rides a bicycle, one will eventually fall. The question is not whether. The question is when.

And when one falls, the severity of one's injuries will be directly proportional to one's height above the ground. The cyclist who has positioned himself low to the ground before he falls, will minimize his injuries when the eventual fall occurs. 

The SWB low racer may be the most practical configuration for many condominium dwellers, who must schlep their bicycles up and down building elevators.

A Fundamentally Flawed Automobile Design 

Imagine that you had designed a performance sports car that contained a fundamental design flaw. What would you do? Change it and eradicate the flaw forever? Or would you persist for the next 50 or so years in making the best of the bad design?

You would have probably gone for the first option. If you had gone for the second then you would probably now be producing a car like the Porsche Carrera 4S - for indeed, that is exactly what German performance sports car manufacturer Porsche did.

Stemming from the Porsche's first sports car, and the first car Porsche produced in it's own right - the Porsche 356 - the Porsche 911 has maintained the basic "rear-engine, rear-wheel drive" layout concept that is a basic flaw in any car design, let alone a high performance sports car.

From "Porsche - A Performance and Sports Car Legend"
The "classic" rear engine, rear wheel drive Porsche is a fundamentally flawed automobile design.

The engine should never have been positioned behind the rear axle in the first place. A tail heavy, rear engine, rear wheel drive automobile is like an arrow that has been launched backwards, with the fletching in front, and the arrowhead in back. The arrowhead naturally tries to get out front, and will do so at the very first opportunity.

Oversteer, the bane of tail heavy, rear engine, rear wheel drive automobiles such as the Porsche, VW Beetle, and Chevrolet Corvair

A Fundamentally Flawed Bicycle Design

By the same token, the conventional upright bicycle is a fundamentally flawed design. The conventional diamond frame bicycle positions the rider vertically, in an upright position, above the pedals, maximizing the risk of injury in the event of a fall.

Conventional Upright Layout is Vertical


Sabrina Bianchi, Second Place Finisher in 2010 RAAM, on a Diamond Frame Road Bike, possibly a Felt

By contrast, the recumbent, an inherently safer design, positions the rider horizontally, in a reclining position, behind the pedals, minimizing the risk of injury in the event of a fall.

Unconventional Recumbent Layout is Horizontal

pedals/feet --- seat/buttocks --- headrest/head

Barbara Buatois, First Place Finisher in 2010 RAAM, on a Factory Custom SWB Performer Low Racer Recumbent

Bicycles: Mechanical Analogs of the Horse?  

So how did the upright layout for bicycles come about in the first place? Why was the rider positioned vertically, above the pedal, diamond frame style, instead of horizontally, behind the pedal, recumbent style?

Mongol Warrior  

A good guess would be that primitive bicycles were mechanical analogs of the horse. Their designers probably had mental images of horses and riders dancing in their heads. In fact, primitive bicycles were referred to as "hobby horses." In China, bicycles are colloquially referred to as "tie ma" or "iron horses."

Pedestrian Curricle, better known as a "Hobby Horse"

It is not surprising that early bicycle designers put riders astride their creations in the same position as equestrians astride their horses.

That said, other bicycle designers were already "thinking outside the box." This early recumbent, circa 1902, was obviously the direct ancestor of today's Easy Racers and Rans LWB mid racers. Not all bicycle designers were mental prisoners, trapped within the upright bicycle paradigm.    

Early Recumbent, circa 1902, designed by one H. Jarvis

Easy Racers Ti-Rush LWB mid racer, note the uncanny similarity to Jarvis' design

Time for a Fundamental Change

The rear engine, rear wheel drive Porsche, and the conventional diamond frame bicycle, are fundamentally flawed vehicle designs that ought to be replaced by fundamentally sounder, inherently safer designs.

The rear engine, rear wheel drive automobile layout should be replaced by the front engine, rear wheel drive layout; mid engine, rear wheel drive layout; or other, more fundamentally sound layout.

The conventional diamond frame bicycle layout should be replaced by the LWB mid racer layout; SWB low racer layout; or other, more fundamentally sound layout.