Profiles of Some American Frame Builders [The Custom Bicycle--Buying, Setting Up, and Riding the Quality Bicycle (1979)]





F. M. Assenmacher

Lightweight Cycles

104 East May Street

Mount Pleasant, MI 48858, USA

Matt Assenmacher is a builder from the "traditional school." Looking into his background, it is easy to see why. He learned to build bikes while he served as an apprentice for a year at JRJ Cycles, Limited, in England (see section 5).

The majority of the American builders use Du Pont's Imron paint because of its resistance to chipping. The British, on the other hand, increase the chip resistance of their paints by their methods of applying the paint. While Imron is fairly easy to apply and it requires a minimum of steps, the British processes require several steps. Accordingly, the actual painting of the frames has become a British trademark.

It comes as no surprise that Matt's bicycles have a very British look. He learned the basics from Bob Jackson. Matt's paint process is involved and can best be described in his own words:

Painting is a six-step process beginning with the removal of all oxides from the bare frame by a light sandblasting. The bare frame is then chemically treated with rust-inhibiting bonding agents which eliminate rust problems and also bond the paint film to the metal.

The frame is then primed and enameled with Sherwin-Williams professional paint system. The transfers and the hand lining are done at this time.

After the transfers have cured, the frame is finished with a special two-part clear acrylic for added durability and gloss. The paint then cures in about 24 hours and the frame is ready for assembly.

Under the paint job, Assenmacher's frames are orthodox in design and construction. Like the Europeans, Matt does not use a jig for brazing the main triangle. Only the forks and rearstays are brazed in a jig. All Assenmacher frames are silver-brazed and are built personally by Matt. His one assistant handles only the cleanup, sandblasting, and initial paint preparation steps. The decision of which gauge and type of tubing to be used is made after Matt learns the size and weight of the rider, his or her riding style, the ultimate use of the frame, and the rider's individual preferences.


Figure 18-1: Assenmacher putting the finishing touches on one of his frames.

Assenmacher, who has been building frames since 1973, currently builds about two a week. In addition to his custom frame building, he has a constant supply of frame repairs for other competitive brands. His frame repair business is strong because people have learned of his quality workmanship. Furthermore, there are proportionately fewer frame builders in the Midwest than in the West.

Assenmacher is eager to please his customers and he will build racing or touring bicycles and tandems. He is particularly cognizant of the needs of the tourist and will supply brazed-on frame fittings in any configuration desired by the customer.

Although he is only 27 years old, he has been an enthusiastic cyclist for over half of his life. Currently he is succeeding in providing the kind of service that is difficult to duplicate when dealing overseas, while at the same time, is building a bicycle that compares favorably with those built by the British.

Bill Boston

38 Franklin Street

PO Box 114

Swedesboro, NJ 08085

It is difficult to find a "unique" American frame builder since, in general, all share an important similarity-they specialize in building individual bikes for individual customers. You could examine their complete production for a year without finding two identical frames. Like his competitors, Bill Boston specializes in matching the individual needs of a rider. He has taken the art of properly sizing the frame one step further, however. He has constructed an "adjustable" frameset with variable seat angles, top tube height, bottom bracket height, and top tube lengths. After personally determining the basic parameters of the "ideal" frame with the customer astride the adjustable frame, Bill attempts to determine the individual needs of the customer-a racing or touring frame, for instance.

Like many of the popular builders, Bill Boston is young. He's in his early thirties. He started building frames, on a part-time basis, in 1972. By 1975, the demand for his products reached the point where he decided to make bicycle frame building his sole livelihood.

After high school, Bill worked for a short time at Du Pont and then joined the navy. For six months of his navy experience he built jet engines. Because of his desire to "learn more about those jet engines than anyone in the shop" he quickly became quality control inspector. After the navy, Bill rejoined the work force at Du Pont and his interest in cycling began.

Bill's introduction to cycling came through his brother who was an avid rider. Bill's real commitment began when he restored a 1937 Drysdale track bike, his first real bike. In many ways, the Drysdale was a major contributor in Bill's decision to manufacture bicycles. The fine construction of the old bicycle was immediately obvious to Bill as he compared it to some of the alleged high quality modern frames. Bill flew to England to meet with Reynolds and discuss his individual tubing requirements. He also visited several of the well-known British builders to pick up ...


Figure 18-2: Bill Boston's frame fitting jig. Note precise fitting in detail photograph (figure 18-3).


Figure 18-3

...pointers. His strong technical background left him disenchanted with the British builders and their reliance on what Bill felt was "feel" rather than technology.

Although Bill Boston's annual production is only approximately 50 frames, or less if there is a high proportion of tandems, the number is not a true indication of his potential. Much of his time is devoted to his hand-manufacture of special handlebar stems (each one takes 12 to 14 hours to produce}, integral alien key seat tube fittings, and custom racks for touring. Bill likes to think of himself as a craftsman and his concern for the quality of his products is greater than the profit associated with the venture.

Initially, all Bill Boston frames were jig-built with brass, but he has since switched to silver. The switch was made after Bill had learned to properly match the bicycle tubes with their lugs, which required, in Bill's words, "remanufacturing the lugs." Although the cost of silver greatly exceeds that of brass, the extra cost is made up in the reduced time required to file and clean the joints when using silver.

According to Bill, it took him over a year to complete his bicycle design theories. Some of his answers were developed on a computer which he used to determine frame stress. Apparently, Bill did his homework well since he appears to be very knowledgeable about the relationship between frame design and the physical capabilities of a rider. Boston makes no bones about the relationship of the seat angle and the rider's pedaling techniques, "if they like to spin they get a steep seat angle. If they don't like to spin and they like to push hard, they get a shallow seat angle." In our travels, we found builders generally had a better understanding of the technical requirements of brazing than knowledge of the mechanics of riding. Boston was an exception.

Bill Boston prides himself on solving the needs of the serious cyclist and he has many methods of building frames for the very short or very tall person. He will not build a frame to meet an individual's specifications unless he feels that the design is sound. Although Bill does build racing bicycles, his forte is touring bicycles. He finds that he has many more touring cyclists for customers than he does racers. Consequently, he has studied and tested his touring designs more frequently.

Francisco Cuevas of Paris Sport Cycle

186 Main Street

Ridgefield Park, NJ 07660, USA

Few craftsmen have been building frames longer than Francisco Cuevas*. In his forty-third year of frame building he is still brazing and designing frames with the same enthusiasm and determination that characterized his idealistic youth. The great frame builders seem to be inexorably drawn by the hope their next frame will be the "perfect frame." Similarly, Cuevas builds each frame as if it were a work of art to be admired and enjoyed.

*As the book went to press, we learned that Cuevas had left Paris Sport Cycle.

Francisco Cuevas also has the distinction of having built frames on three different continents. He started building frames in 1925 when he worked for a factory in his hometown of Barcelona, Spain. In 1928 he started his apprenticeship under two Spanish frame builders, Ernesto Bayo and Jose Magdalena. By 1932 Cuevas was confident of his ability as a frame builder and he opened his own frame-building shop in Barcelona. His success was not immediate, however. His competitors claimed that he was too inexperienced to be proficient. His products proved otherwise.

Through hard work and discipline the talented Cuevas quickly established himself as one of the major frame builders in Barcelona.

In the 1930s Spain was a time bomb of political unrest. The political factions exploded into a full-scale civil war and Cuevas found that the emotionalism of the time led him to join the Loyalist forces. Forsaking his shop, he began a life pledged to establishing a stable democratic rule in Spain.


Figure 18-4: Cuevas with apprentice.

When Franco's army firmly established itself as the ruling authority, Cuevas fled across the border to France where he spent eight months in a refugee camp.

By late 1941 the political situation had normalized and Cuevas returned to Spain. He reopened his shop and again began building frames. Once again his shop prospered, but the situation in Spain continued to deteriorate.

In 1951, unable to tolerate the political regime, Cuevas left for Argentina. He spent 18 years in Argentina as a successful frame builder where his firm, Ciclos Cuevas, employed four assistants.

He developed a close association with the bicycle federation and became the technical director of the Mendoza district bicycle federation. Unfortunately, the political situation in Argentina in the 1960s was highly explosive and again Cuevas felt that he had to leave. He emigrated to the United States in 1969.

Cuevas individual success in the United States has been marginal. Without the capital investment needed to establish another shop, he was forced to work as a bicycle technician and consultant in many of the larger bicycle stores in the New York City area.

Since 1976, Francisco Cuevas has firmly established himself with Paris Sport Cycle which provides him with a frame-building workshop. Although the frames he builds all bear the Paris Sport label, they can be distinguished from Paris Sports' "other" master builder, Pepi Limongi, by the signature on the rear chainstay of the frame.

Cuevas is a builder from the "old school" of frame building who believes that it is imperative to learn how to handle a file properly before even looking at a torch. According to Cuevas, learning how to handle a file requires years of careful filing and finishing frames.

Cuevas welds with either silver or brass. Since he is so familiar with the effects of heat on lightweight bicycle tubing, he feels that the normal objection to brass (increased possibility of overheating the tubes) doesn't exist in his case.

All the tubes are spot-tacked to insure correct alignment of all frame dimensions. Cuevas does not use frame jigs because he feels that the expansion that takes place when heating the tubes must take place unhindered, otherwise the frame will distort upon cooling, requiring much more bending when cold setting the ...


Figure 18-5: Nearly 50 years of experience guide the hands of craftsman Cuevas as he files the fork crown tangs.

... frame. With his years of experience he finds that he can second guess the reaction of the tubing, thus eliminating the need for extensive cold setting.

Mike Fraysse, owner of Paris Sport Cycle, advised us that Cuevas will build almost any frame size imaginable-from 18 inch racing frames to 28-inch touring frames. The large-size frames he designs handle well, according to Mike, but in the European tradition, he would rather see a tall person ride a frame that is as small as possible because a smaller frame will naturally handle better.

Albert Elsentraut

1000 Twenty-second Avenue

Oakland, CA 94606, USA

Albert Eisentraut is probably the most famous of the current American frame builders. The story be hind Eisentraut is especially interesting because it is a real-life example of what often happens when a small, high-quality frame builder tries to meet his demand by increasing the number of employees and semi-mass producing frames. Because of poor capitalization, quality control, and labor problems, Eisentraut has abandoned the project, reverting back to the production style that made him famous: He once again builds all of the frames himself.

Before we look at Albert's current frame-building operation, let's look at the events that contributed to the man and his bicycles.

Since he grew up in a cycling family, Albert Eisentraut's experience more closely parallels that of the European frame builder than any of his American counterparts. Albert's father was a prominent bicycle racer who actively competed in the 1930s.

His close friend was Oscar Wastyn, Sr., the well-respected frame builder and bike shop owner. From the age of three, Albert visited the shop regularly with his father, and in 1955, at the age of 15, began working for Oscar as a bicycle mechanic. Oscar liked Albert and would spend hours talking and philosophizing with him on the merits of cycling. At the same time, Albert's father, an adept welder by profession, taught his son how to braze. Both Oscar and his father became major influences in his life.

Albert's technical skills continued to improve while he at tended the Illinois Institute of Technology's program for mechanical engineering. In addition to his formal education during the day, Albert worked part time in an ironworks where he became more familiar with machine tool operation. He built a few experimental frames at that time, although "they were recreational frames for my own amusement." Throughout this time his interest in bicycle racing continued to grow and when he joined the army in 1961, he was at his racing peak.

The army recognized Albert's racing experience (a second place finish in the Illinois state championships, a tenth-place finish at the national championships, and numerous individual race victories) and placed him as one of the members of its cycling team. The army stationed Albert in Oakland, California, and, after his stint with the army, he entered San Jose State College. Four years after leaving the army and a curriculum change later, Albert received a B.A. in art. Two years later, in 1967, Albert received a teaching certificate and an M.A. in ceramic sculpture. As an undergraduate Albert worked part-time as a bicycle mechanic and continued to experiment in frame building. Even when he was a full-time graduate student and teaching assistant in art, he continued to work on various aspects of frame building. In 1969, after teaching for two years, Albert decided to devote his full attention to frame building.

The Eisentraut frame has gained strong popularity among American racers. This is particularly unique since most of the production of the American builders is usually touring bicycles.


Figure 18-6: Eisentraut examines a custom lug.

The top American bicycle racers ride the prestigious European frames. Of the many American bicycles, only the Eisentrauts and the Schwinn Paramounts have gained wide racing appeal. How did Eisentraut earn his reputation? Albert is a major influence in modern American cycling partially as a result of his successful synthesis of his many years of experience. Although he is only 38, he had been producing custom-made bicycles years before the bicycle boom. Maximizing the benefits of his racing experience, his technical skills, and his artistic talents, Albert was able to design and produce a frame that was aesthetically pleasing and technically sound. He could offer his customers more than just a well-brazed bicycle; he could interpret their physical requirements into an efficient frame design. In response to the great demand for his frames, Albert chose to meet that demand with a semi-mass produced frame called the "Limited." By semi-mass producing the Limited, Albert was able to meet his demand with a less-expensive Eisentraut frame. But, because of the lack of capital investment needed to adequately mechanize many of the frame-building procedures and the shortage of qualified labor and its attendant quality control problems, Albert abandoned the project. He found that he sometimes produced a substandard Eisentraut frame, not the quality product with a reasonable price tag as he had envisioned at the commencement of the project. As Albert described his problems, it sounded reminiscent of complaints voiced by other famous builders in Europe. Albert found that "Unskilled people ... don't particularly care and they don't think that it's [the assembly process) particularly important and the kind of work they turn out is definitely substandard. The more skilled people very quickly tire and want to make more money." But where does this money come from? Virtually every builder we spoke with is motivated by the desire to create a quality product-not by the desire to turn a large profit. As a result of Albert's unsatisfactory experience with the Limited, he has decided to return to being a one-man operation that exclusively specializes in custom frames.

Albert builds all of his frames on jigs. The tubes are mitered on a lathe and the frames may be brass- or silver-brazed depending usually on the gauge of the tubing being used. For Albert, the gauge of the tubing is very important and he selects his tubes according to the design requirement of each frame and not according to what an individual tubing company offers. Consequently, a single Eisentraut frame may be built with more than one kind of tubing, whether it is Columbus, Reynolds, Ishiwata, Tanguy, or Super Vitus.

The frame jigs which Albert uses are interesting because he has designed them to allow for expansion of the tubing during the brazing process. This reduces the tendency of the frame to have inbuilt stresses. Once the frame has been built and cleaned, it is finished with Du Pont Imron paint, a standard practice among many of the quality American builders.

Through the years Albert has kept all of the sizes of his customers and the dimensions of their respective frames. He uses this information to assist in sizing each new customer. He also uses an interesting variation on determining the length of the seat tube. To calculate the length of the seat tube, he requires a rider to be measured while laying on the floor with the balls of his or her feet against the wall. This will usually result in the foot extending toward the wall at approximately a 45-degree angle. With Albert's method, the inseam measurement to the wall will include the effect of foot size.

Recently, Albert has developed investment cast lugs which are relatively lightweight and are more accurate than the normal pressed lug. He has no intentions of producing them commercially, however.

The bicycle purist should be happy to know that the United States' strongest candidate for the title of master builder has returned to personally producing all Albert Eisentraut frames and that once again we can buy a frame with the quality that made the name famous.

Bruce Gordon Cycles

27729 Clear Lake Road Eugene, OR 97402

Unlike many American frame builders, Bruce Gordon seems to have a very businesslike view of frame building. While some are artisans who do not care to be bothered with the day-to-day problems inherent in a business, Bruce tends to be a careful technician who is as skilled at talking about frames as he is competent in building them.

Although Bruce is just barely 30 years old, he has a varied cycling background. He was employed as a bicycle mechanic for two years and then became a manager. After three years of store management, he found that he longed for work that required making expressive use of his hands. In 1974 he started working as an apprentice for the frame builder Albert Eisentraut. Soon he became a part owner in the newly reorganized corporation. But like many partnerships, the owners sometimes had trouble agreeing on the direction and philosophy of the company. In 1976 Bruce sold his share of the business to Eisentraut and moved to Oregon to start his own frame-building operation.

Bruce Gordon is a perfectionist and he believes that it is virtually impossible to produce near-perfect frames without the finest machinery available. His annual production of 100 to 125 frames per year is the result of his large capital investment in machine tools and his organized business sense. Every sequence in the frame-building operation is done with the most sophisticated equipment appropriate to the particular job to be performed.

Tubes are mitered precisely with a milling machine. Several custom-made jigs are employed for each step of the frame-brazing process.

Bruce has his own sandblasting booth. He believes the booth is necessary to properly clean the tubes and lugs before and after the brazing process. Although he has the paint work performed by someone else, he is in the process of setting up an area to do his own. Like many American builders, Bruce uses only Du Pont Imron paint.

During our interviews of frame builders we found that few really understood the business fundamentals necessary to operate a successful business. Accordingly, a surprisingly large number of American builders went "out of business" during the preparation of this book. Bruce, on the other hand, recognizes that his large investment in machinery may never reach the levels of return expected by the average investor. He believes that the equipment is required, however, to produce a truly top-quality frame. He is the first builder that we spoke to who shares our belief that some builders are required to charge high prices since they haven't spent time researching how to perform each required step in the frame-building process on an efficient, as well as, high-quality basis.

Technically, Bruce Gordon is conservative compared to other young American builders. He silver-brazes with Reynolds or Columbus tubing and doesn't believe there is any great difference between the two brands of tubing. He believes that matching the gauge of the tubing to the ultimate use of the bicycle is more important than what brand of tubing is used. His bicycles are built with Cinelli or Prugnat lugs and they usually include the Cinelli semi-sloping crown and investment cast bottom bracket. His fastback stays are his "trademark" and are built with a normal seat lug that has had the "ears" removed and a plate welded over the gap.


Figure 18-7: Hands of craftsman Bruce Gordon doing finishing work around the lug.

When we asked Bruce his opinions on how long it takes to become a skilled frame builder, his answer was unique. He believes that the easiest part of the frame-building operation, the paint finish, can be learned in six months. The actual development of brazing skills varies with two major influences-the skill or training of the builder and, most important, the number of frames that have been built in a specific time period. For instance, Bruce learned his brazing skills while brazing 20 to 25 frames per week for Albert Eisentraut. How long would it take to develop the mysterious, or hard to define, touch if a builder only builds 20 to 25 per year? The interval between frames may be too long to provide adequate feedback.

Although Bruce has not had a long history of riding experience, his contact with riders has aided him in solving design problems. He cautions mail-order customers to be very careful in taking their measurements for their custom frame. Jokingly, he told us he would like to have a wax museum because he could fill it with unbelievable examples of mankind if some of the measurements he has received were true. Fortunately, he spends a great deal of time checking the measurements for plausibility before he begins to design the appropriate frame. Bruce's second concern involves the inability of some customers to describe the type of bicycle that they desire. For instance, Bruce frequently receives orders from customers who request a "stiff" frame. But, how stiff is "stiff"? To the owner of a touring frame with light-gauge tubing almost anything would be stiff. The opposite is true of a rider who requests a bike that is stiffer than his Cinelli track bike. Any prospective customer should define his desires in comparison to known quantities.

Like most of the better American builders, Bruce Gordon specializes in designing and building the perfect frame for a specific individual and his or her specific use. He builds tandems or singles, racing or touring frames. Most important to the tourist, Bruce builds his own touring racks which are designed to complement his touring frame geometry.

Proteus Design

9225 Baltimore Boulevard

College Park, MD 20740, USA

Proteus Design was conceived in the late 1960s by three bicycle enthusiasts. What started out as a bi cycle store, has evolved into a frame-building shop producing seven different models which include both touring and racing styles.

Barry Konig has been the prime motivator and driving force behind the development of Proteus Design. Since he and his partners were very young when they first opened the doors of Proteus Design, their imagination created a Dr. Paul Proteus with whom the bicycle industry could deal and feel confident that Proteus Design was a mature and businesslike establishment-not one, as Barry puts it, "run by a bunch of young punks." To this day the charade is continued, however, Barry freely admits that Dr. Paul Proteus exists only in their hearts. Reaching his thirties, and having spent 10 years in the bicycle business, Barry feels that the quality of his work speaks for itself.

The original owners of Proteus Design decided to build frames since their bicycle shop was thriving and they were looking for another challenge. They were mechanically inclined and felt confident that they could produce an acceptable product.

Their initial step was to depart for England and try to apprentice to a builder, although the best they managed was a three-week stint at the Falcon factory in England in 1973. Barry says that they learned a lot in those three weeks and upon their return they commenced building their own frames. Of the three original owners, only Barry remains actively involved in the business, but even Barry does not build frames anymore. He, however, has helped train many of the frame builders that Proteus has employed in the past five years. Presently, the head of the frame shop trains all new frame builders in the Proteus design philosophy.

What is the Proteus method of frame building? Proteus Design incorporates the use of a lathe in mitering tubes for two reasons. The lathe expedites the operation and makes a precision cut at the same time. Barry believes "the strength (in a frame) comes from the joint and not so much from the lug, therefore mitering must be exact." He believes that 100 percent accuracy can only come by using a mitering machine.

He also believes that the best kind of fork crown is a semi-sloping investment cast crown. Proteus had been using various brands of crowns but Barry decided that they could eliminate some quality control problems by having an American firm make the fork crowns. Consequently, Proteus designed its own crown along the lines of the Cinelli semi-sloping crown, and subcontracted the design to an American company. The Proteus investment cast semi-sloping crown presently is used almost exclusively. Besides the fork crown, Proteus also has various brazed-on fittings, such as fork tangs, water bottle mounts, and brake cable stops, made to what Barry calls "our own exacting specifications." Silver brazing rod is used exclusively on all Proteus frames because of its lower brazing temperature. On the rear dropouts, however, where the area to be filled often exceeds .003 inch (the properties of silver braze will not insure a strong joint when the area that is to be filled is larger than .003 inch), brass is used.

All frames are built exclusively with Reynolds tubing and Proteus stocks many of the different gauges, thus giving the customer a wide variety to choose from. Barry prefers Prugnat lugs and stocks them in 71-, 73-, and 75-degree sizes. By stocking ...


Figure 18-8: One of the four or five frame builders at Proteus Design. Here shown reaming out the bottom bracket chainstay opening.

... the three different sizes, only a small amount of bending is required to suit the wide range of angles found on Proteus frames.

Different seat clusters are used on the various models although Barry personally believes that the Italian fastback is the strongest.

Painting is done on the premises. Each frame receives a coat of Du Pont epoxy primer followed by a topcoat of Du Pont Imron available in 100 different colors. Both coats are baked on to further prevent chipping.

Proteus Design is different than all the American builders that we have featured in this section. None of the other builders we have included own their own bicycle shop. All are strictly frame builders. Proteus, on the other hand, started out as a bicycle shop that went into frame building in 1973 as an expansionary measure of the bicycle store. All the other frame builders in this section build one-of-a-kind frames whereas Proteus seldom does. Proteus is primarily geared to produce a semi-mass produced frame. With the way their tubes are precut and mitered ahead of time, they cannot vary the design greatly in order to custom-build a frame.

However, they can build a frame that will satisfy the average frame customer in far shorter time than the small custom builders who usually have a very long waiting list for their products.

Proteus Design is the national distributor of Reynolds tubing.

They supply many braze-on sundries to other frame builders and they are the only builders in the United States that are currently authorized to build with Reynolds 753.

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