Classic Corner

Here's what makes a custom bike custom

By Greg Overton

Recently we had a conversation with a customer who was questioning why a custom bicycle frame is considered to be the best purchase for one's "Ultimate" bike.

We talked about it backwards and forwards, and up and down until the subject of cost was the only thing left to talk about. We had both been avoiding it to that point. His reaction? "Whoa, for that much dough, the thing should weigh nothing! I can get a complete bike that'll be lighter, and cost less than this frame."

"You're right", we said. So why IS a traditional custom frame still considered -by most- the best investment for the long term?

Craftsmanship, manipulation of ride quality to fit the rider, characteristics of handling to meet the rider's size, weight, and riding style. Aesthetics tailored to the individual. All of these are reasons to want a custom built frame.

But why do they, at least the good ones, cost so much when the technology and processes have been around forever?

We asked a couple of frame builders these questions, and asked them to sort of walk us through the process. Here's what we learned.

The initial conversation between a builder and customer is focused on the rider's measurements, including inseam, length of femur, torso length, upper arm, lower arm, shoulder width, and overall height. Some builders even discuss the rider's muscle flexibility and elasticity to help determine the relationship of saddle and handlebar. The rider's weight is measured. And a lengthy conversation about the type of rides typically chosen, the specific road surfaces of the most travelled roads, and the terrain. Sometimes, even the components to be used on the bike are discussed.

The framebuilder will then use all of this information to design a bicycle for the customer.

Design a bicycle? They've been around forever, especially lugged steel bicycles. Just copy a DeRosa, right?

Well, that's good enough for the Classic Corner crew for sure, but we're pretty sure a customer paying a bunch of money doesn't want to find out that part of the price went for a DeRosa in his/her size to copy.

So we asked a couple of builders to explain this frame design issue for us, and we learned a lot.

First of all, most of the designing goes into parts of the frame that you don't see, or can't readily pick out.

For instance, based upon a particular rider's information, the builder may choose top tube, down tube, seat tube, chainstays, seatstays and fork all from different tubing models and even different brands to create the optimum ride quality to meet the customer's goals and needs. This means the builder has to know how each of these particular tubes rides and reacts in each part of the frame.

Maybe Columbus EL/OS is the best downtube for this rider, but too stiff for the chainstays to get the compliance that the rider wants. And Reynolds fork blades mated to a Henry James crown will offer sure handling. but less road shock.

An experienced builder will request particular tubes in differing wall thicknesses to achieve certain ride characteristics, or cut a tube leaving only one of the butted sections in the frame to tweak the ride a little here and there. Potentially, this could mean that one frame will require the builder to purchase up to six tubesets, unless it is a builder with enough clout to have suppliers send only the tubes requested.

Lugs are also chosen with regard to the targeted finished product, albeit with the customer's aesthetic tastes considered. Some lugs are not known for their accuracy of diameter or angle, and require manipulation by the builder to fit properly. The builder must know the compatibility of certain lugs and tubing well, because the embarrassment of telling a customer to select his/her second choice after finding that this chainstay does not fit into that bottom bracket will not enhance the builder's reputation. All of this work is usually put on paper and worked through before the framebuilding begins. At least it should be.

Once the design is settled upon and any materials that are needed are ordered, the process of preparing the tubes and lugs begins. All are cleaned thoroughly to ensure good brazing penetration, and the tubes are cut to proper length. After cutting the tubes -which can be very difficult with the hardness of most new tubing material - the tubes have to be mitered. Mitering is the filing of the ends of each tube to fit uniformly with the tube that it meets inside the lug.

This is a common shortcut by many builders,because it cannot be checked by the customer after the frame is brazed. A poorly mitered frame will be weaker than it should. And it's a good bet that a builder who takes shortcuts you can see in the finish work also took shortcuts on the inside!

After many "dry fits" of assembling the tubes to check the mitering and fit of the lugs, the main triangle is placed in a fixture to hold it securely at the angles determined by the particular design. Most of the best builders will drill small holes into each lug and through the tube in which he inserts a "pin" (some builders even use small nails for this).

This pinning process prevents the tubes from twisting under the heat of the torch and creating a misaligned frame. You can feel these pins with your finger inside the chainstays, downtube and seat tube just before they meet the bottom bracket opening on an unbuilt frame.

Next comes the "tacking" process of just brazing a small area of each joint to hold there, and then double and triple checking alignment of the main triangle. Once the builder is satisfied that all is well, the joints are brazed in a sequence that does not keep the flame on one joint for too long, as this can distort or weaken the tube or lug. The sequence, flame temperature and amount of time spent in one area are all part of a learned process that only experience can teach properly.

Once the main triangle is brazed and the builder is satisfied, the rear triangle is cut, mitered and brazed in a similar process, with additional care placed on the alignment of the dropouts. At this point, the rear triangle is "dry fitted" to the main triangle, mitered further if needed, and brazed to the bottom bracket and seat lug. After cooling, the frame is checked for alignment, and construction of the fork begins.

Fork blades are usually supplied as straight tubes, and bent by the builder over a fork mandrel, so that the proper fork rake for a particular geometry can be achieved. The steerer tube and crown are separate pieces and must be pinned and brazed together and the base of the steerer tube must be machined to accept the headset race. Care must be taken to ensure uniform diameter and cut so that the race sits squarely and evenly on the fork. Next comes pinning the blades into the crown and cutting the fork ends to accept the dropouts. More dry fitting, filing and then brazing. After a few hours' work, you have a fork.

Now there is a bicycle frame, but all of the joints look like really ugly, bubbly welds with discolored metal and dried brazing materials. Time to turn on some good music, take a deep breath and start filing.

Each joint on the frame must be filed. That nice, crisp lugwork you see on a beautiful frame took hours and hours of filing to remove the remnants of the brazing process and create a sharp line around the lug. Special files are used to conform to the shape of each lug, and inside any cutouts or drilling in the lugs. But care must be taken to not mark the tubes with the files. This is a major source of pride for many builders, as it shows plainly that extreme care was taken even on this most tedious task.

At this point, there are about forty five to fifty hours invested in the frame. How much do you make per hour? How much does that frame wholesale for? Oh, and now you'd like custom paint? All this plus the cost of tubes, lugs, tools, paint, rent etc. Framebuiding is definitely a labor of love for those who do it well.

Any wonder why the trend in production is/has gone away from custom lugged bikes to tig welding? One tubeset, carbon fork, no filing, no finish work, alignment (maybe) after completion (by bending) , and the weight and cost of lugs is avoided. Ride quality can't be quantified in an ad, so it doesn't matter. Even many small builders are getting the picture and increasing their bottom lines by riding the wave. Good for them, they deserve a payday. But don't mistake a pretty color and light weight for craftsmanship, or necessarily quality. And the next time you meet a framebuilder, buy him lunch!

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