The Bicycle: Evolution or Intelligent Design. Part II

This is Part II of a three part series, If you haven’t already read Part I, you can read it here.

Soon after the chain driven bicycle was invented in 1885, a whole bicycle industry sprang up in Britain. Bicycles were mass produced, making them affordable for the working man. For the next 60 years the bicycle became the working man’s form of transport. And bicycle racing the working man’s sport.

Because Britain was the first to industrialize bicycle manufacture, certain standards were set, and the rest of the world followed. The half an inch pitch bicycle chain is a good example, it is still the standard today worldwide, even in countries that have always used the metric system of measurement.

Bicycle frame tubes were a standard 1 1/8 inch seat and down tubes, 1 inch top tube, 1 1/4 inch head tube. With the exception of the French who used metric size tubes, most of the rest of the world used the Standard English size tubes, even the Italians. And this would remain the standard, especially for lightweight racing frames for almost 100 years.

The horizontal, level top tube became standard. It was the framebuilder’s point of reference. All other angles were measured off the top tube, it was parallel to a line drawn though the wheel centers. (Assuming both wheel are the same size.)

Traditionally, lightweight frames were custom built, one at a time. My mentor, Pop Hodge, would assemble a frame, measure all the angles and tube lengths. Then lay it out on the brick floor of his shop. The top tube would line up with the edge of a row of bricks. There were marks scratched into the bricks where the Bottom Bracket should be, the same with the rear drop-outs, the bottom head lug, etc.

He would then drill a hole with a hand cranked drill, (He used no power tools.) and pin the tubes in the lugs with a penny nail. (A penny nail was a reference to its size.) When the whole frame was assembled, he would place it in a hearth of hot coals, (Again with a hand cranked blower.) Heat the whole joint to a light red heat, when he would feed in the brass, and braze the joint.

The first framebuilders were blacksmiths, and Pop Hodge had been building frames since 1907 built in that traditional way. He had a hand held torch that he used to add braze-ons and other small parts. It burned coal gas, from the town’s supply that was piped in to all homes and businesses for cooking and heating. The flame was boosted by foot operated air bellows.

The level top tube also had the advantage that once a person established what size frame suited them, any make of frame in that same size would fit. Even though seat angles, and top tube lengths may vary, it would only be slight and could be taken care of with a longer or shorter handlebar stem.

The main reason different makes of frames worked as long as the frame size was the same. When the saddle was set at the correct height, and the handlebars would then be automatically the correct height in relation to the top of the saddle. No one spoke of “Handlebar Drop,” it was an unnecessary measurement, as long as the top tube was level.

In the late 1950s and through the 1960s there was a huge social change taking place in the UK and the rest of Europe. Economies were booming, (Because of the WWII recovery.) and the working man was buying a car for the first time. My parents never owned or even learned to drive a car, but the younger generations were abandoning their bicycles and buying a car.

Even the racing cyclists, mostly owned one bike. They rode to work on it, which was a big part of their training. On the weekends, the fenders (Mudguards.) and saddle bag came off, racing wheels were fitted, and a time-trial was ridden.

For many cyclists, Time-Trialing in the UK in the 1950s and before was more a social event than a serious athletic event. Owning a car for the first time changed the whole social structure of the working man, and many gave up cycling completely.

The result was a huge slump in the bicycle business at all levels. Prices of lightweight frames remained stagnant for many years and framebuilders had to look to ways to cut costs. The ones who survived were the ones who moved away from building frames one at a time, and managed to produce large numbers of frames sold at a reasonable price. See top picture.

I mentioned in Part I of this series, that the standard racing frame geometry of that era was 71 degree seat angle, 73 head. To simplify the design the parallel frame was introduced, that is one where the head and seat angles are the same.

People were not ready to make a big jump from 71 to 73 degree seat angle, so a compromise was made and the 72 degree parallel frame was introduced. Advertised as a “Massed Start” or Road Racing Frame, the parallel frame had the advantage that a complete range of sizes could be made using only two, maybe three top tube lengths.

Simple jigs were used to assemble the frames, the same length top tube could be slid up or down between the parallel head and seat tubes, to build several different size frames. Maybe not the ideal set up, but it did cut the cost of building frames, and as I mentioned before the reach could be adjusted with a different length stem.

Tubes could be pre-mitered using the same angles, another time saver. By the mid-1960s the parallel frame concept was accepted by most people, and the 73 degree parallel became the norm. 73 was a better head angle, and riders soon found that the 73 degree seat was better too. Less tendency to slide forward on the saddle.

So once again here was a trend started by framebuilders because it suited them, but actually lead to a better riding bike. This series will have to run into a third part. Next I will touch on the steep head angle trend of the 1970s and how that came about, and then bring the story up to the present day.

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The Bicycle: Evolution or Intelligent design. Part I

The chain driven bicycle was invented almost 130 years ago. (Picture left, The Rover "Safety" Bicycle 1885.)

To the layman, or the untrained eye, this bicycle is basically the same as today’s bike.

But its geometry was directly influenced by its predecessor, the High-Wheeler. And that would influence frame design for the next 60 years. Indirectly it had an influence on what we ride today.

I have been riding bikes, racing bikes, designing and building bikes, and writing articles about bikes for 65 years, which is half of the period chain driven bikes have existed.

Albert “Pop” Hodge, who was my mentor, and first introduced me to the art of framebuilding, was born in 1877, and therefore witnessed firsthand the invention and early development of the bicycle. Pop Hodge was close to 80 years old when I first met him around 1953. (Picture below right.)

From what he told me, and what I have observed, back then and since, in the 130 years the bicycle has gone through a slow evolution.

During each phase, what happened previously affected the design of the next generation of bicycles.

The title of this piece has religious overtones, because like religion, much is spoken and written about the bicycle because “It is so.”

The center of the knee shall be over the pedal. But why? Because it is written. Wise men have deemed it is so.

When I started racing in 1952, we rode bikes with a seat angle of 70 or 71 degrees. We were taught that the shin of the lower leg, should be vertical. The center of the knee was actually behind the pedal. Wise men taught us that in order to pedal fast, and efficiently, one had to sit back.

In practice I soon found this was not so. When making a maximum effort, and pedaling at maximum revs, I found myself sliding forward on the saddle, which was uncomfortable, distracting, and had the effect of the saddle being much too low.

The term “Riding the Rivet,” is still used today to describe a cyclist making a maximum effort. The term was around when I began racing in the early 1950s when saddles were leather and actually had rivets to hold the leather to the saddle frame.

To understand why seat angles were so shallow back then, one has to go all the way back to the predecessor of the chain driven bicycle, to the “Ordinary” or Penny-Farthing bicycle. (Left,)

This was the first “Enthusiasts” bike. One had to be an enthusiast, as well a young, fit and agile athlete just to mount and ride one of these.

Today’s cyclist might think it a problem to make an emergency stop with their feet clipped in. Imagine making an emergency stop on a High-wheeler, and you are sitting over five feet above the ground. One had to dismount in a hurry, or fall over.

When the chain driven bike was invented in 1885 it was not immediately accepted by the enthusiast. These enthusiasts were the hard core “Roadies” of their day. The high-wheeler or Ordinary was still much faster. It wasn’t until pneumatic tires came into being in 1888 that the chain driven bike became faster and was accepted by the enthusiast.

These enthusiasts were the experts of the day, and what they learned riding the Ordinary influenced them and carried over to the chain driven bike. The Ordinary was limited by its simplicity, as to where the rider could sit, for example.

Imagine if your handlebars were directly above your bottom bracket. There would be no other choice but to sit some considerable distance back behind the pedals. When the first “Safety” or chain driven bike came into being, it was designed so the handle bars and the saddle were positioned in relation to the pedals exactly the same as its predecessor the High-wheeler. Making a seat angle of around 69 degrees. (See picture above.)

(Above.) Two different bicycles, but the exact same rider position. Note the rider's shin is vertical, a positioning "Guide" that would last another 60 years into the 1950s.

Below is a typical racing bike of the 1950s. Louison Bobet's 1954 Tour de France bike. Its shallow seat angle can be traced back to the High Wheeler of the 1800s.

A generation of “Experts” who had learned to pedal on the High-wheeler, then taught the next generation who became the following generation’s experts, and so on for the next 60 years and into the 1950s when I came along.

There was another factor that maintained this notion that seat angles shall be shallow, and an important one. This I would learn from framebuilder Pop Hodge. Frame lugs were heavy steel castings, and they were limited in the angles that were available.

It suited lug manufacturers to make their product in a limited number of angles. In later years thinner pressed steel lugs became available and it was then possible to alter an angle slightly. But not so prior to the 1950s.

73 degrees was established as an ideal head angle sometime in the 1920s or 1930s. This is still the norm today, and in the past when I have experimented with steeper or shallower head angles, I found no improvement.

Building frames with a head angle of 73 degrees, and a seat angle 2 or 3 degrees shallower, suited the framebuilder. With the head tube steeper and the seat tube leaning back away from that angle, as the framebuilder built a taller, or larger frame the top tube automatically became longer, which made the framebuilder’s job easier, and suited the taller rider.

This article is based on a talk I recently gave at the Philly Bike Expo, and will have to be written in two parts. In the next piece I will explain what happened after the 1950s. How the 73 degree paralell frame, still a popular design today, came about. The reason may surprise you. 

Two main factors determine frame design, throughout history and even to this day. Experts who simply re-cycle information that was written by previous generations of experts. And framebuilders and manufacturers doing what is easiest and most profitable for them.

Read Part II.

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Everything Clamp-on

The pictures here are of a 1968 Pugliaghi. Everything clamp on even the bottom bracket gear cable guides. Pictures from TheRacingBicycle.com

In the late 1950s through the early 1970s there was a slump in bicycle sales in Europe. In the 1960s the economy was booming and although in many places the bicycle had always been the mode of transport for the working classes; many were now buying cars for the first time. At the same time the fitness craze of the 1970s had not yet begun.

Racing bicycles and framebuilders were also hit by this slump and the price of a frame rose very little in that decade even though inflation did. Framebuilders had to look for ways to cut costs and one of them was to leave off all braze-ons.

Building a frame without braze-ons does save a considerable amount of time and therefore labor costs. The only braze-ons seen in this era was a chainstay stop and sometimes a little stop under the down tube to prevent the gear lever clamp from sliding down the tube. 

Having done that framebuilders could not tell their customers they were doing this to cut costs, hence the story that braze-ons weaken the frame. I think Cinelli started it; framebuilding was never their main source of income (Handlebars and stems were.) so the price of a Cinelli frame was always high. Everyone’s thinking was if Cinelli can get away with it so can we, and most framebuilders followed suit.

Do braze-ons weaken the frame? Maybe very marginally but it is part of the framebuilding process. I have seen down tubes break right at the clamp on gear lever. Imagine a shock wave from hitting a bump in the road, or the twisting forces on a down tube.

Normally these stresses would be dispersed around the frame, but instead are stopped rather abruptly by a solid clamp around the tube. Clamps require more maintenance they collect moisture under them and if over tightened can dig into the tube and start a stress riser.

Prior to the “No Braze-ons” craze, all the various derailleur manufacturers provided clamp-on fittings because there was no standardization in gear lever design, for example, and clamp-on gear lever had already been standard practice for the most part.

By the 1970s, when braze-ons made a return, Campagnolo so dominated the market that most frames (Especially Italian.) came with a Campagnolo brazed on lever boss. Other manufacturers (Shimano for example.) were forced to design their gear levers to fit the Campagnolo lever boss. 

I do feel if anyone is restoring a bike with a “No braze-ons frame” from this era should keep the cable clamps because they are authentic for that period.

Footnote: Re-posted from March 2006 with aditional content added.

                          

Old "Cycling" article from 1976

A friend came across an old copy of the British “Cycling” weekly magazine from 1976 offered for sale on eBay. It contained an article I had written about frame design. He bought it and sent me a PDF copy.

It seemed strange to read the words I had written almost 37 years ago, and I could not help but wonder what some of the older established framebuilders of that time thought of me. Many had been in business a lot longer than me.

But to me the proof of the bike was in the riding. So often when riding a new bike a rider needs a week or two to get used to it, but so many times I had riders take delivery of a bike on Saturday, and do a personal best ride or even win a race the following day on the new bike. I felt confident that I was doing something right.

I had been questioning conventional frame design since the 1950s, and had been experimenting with my own frames since the early 1960s. I was a rider of somewhat short stature, 5’ 6” (168cm.) and I always felt that because all racing bicycles have the same size wheels, my bikes were a cut down version of a larger frame. Cut down rather than scaled down.

It also did not go unnoticed that the top riders in the world were between 5’ 8” and just under 6 feet. In other words the ones who would fit on the mid-size frame around 56cm to 58cm. When I think about it, it is not much different than today. There are always exceptions of course, and the average range today is probably something like 5’ 10” to 6’ 1”.

It has always been the case throughout history that the people who build bikes do not race them, and top riders who race do not build them. One exception I can think of is Eddy Merckx, who went on to open a successful frame building business after he retired. But even Eddy Merckx fits neatly into that mid size range riding a medium size frame, so can he appreciate the needs of someone much shorter, or indeed taller.

Framebuilders in the past have always done what suited them, lugs somewhat dictated the angles, rather than the angles being altered to suit the rider. And carbon fiber frames built today from what I have noticed seem to follow the tried and tested geometry of the old lugged steel frames that preceded them.

I can fully appreciate that it is a costly proposition to make a mold for a frame just to experiment; one would need to make a welded steel or some other metal prototype fist. And where can such a prototype be tested under race conditions when the UCI now bans the pros from riding prototypes,

One area that could be looked at is fork rake (Offset) which seems to have increased in recent years to around 45mm. A shorter rake, as much as a centimeter, bringing it down to 35mm would increase the amount of trail and would make the bike more stable, and hold a tighter line when cornering.

I notice what seems to be an awful lot of crashes in races, and wonder why this is. Are bikes today more skittish, or it could be we are now seeing more videos of the complete race, and we just didn’t see some of these crashes before?

See the PDF file here The first 2 1/2 pages are written by me, the rest are from other contributors.

                         

Weight Distribution

It was pointed out to me recently that of all the articles I had written about bicycle design, I had not written one about weight distribution.

It is a subject that while somewhat important, it is not as important as a good riding position, and once a frame or bike is built and the rider has set it up to his or her absolute best position, are they then going to alter that position to achieve a certain weight distribution? That would be counter productive.

The rider is the engine that propels the bike forward, and a proper riding position is of the utmost importance for the body to work at maximum efficiency. I am talking of the racing cyclist who is looking to get optimum performance from body and machine.

If you are riding for leisure or exercise, you may sacrifice some efficiency for comfort, especially if you are older or not in top physical condition. You will adjust your riding position accordingly and weight distribution is probably not important enough to be even thinking about.

Under normal riding conditions there is always be more weight on the rear wheel that the front, simply because of the mass of the rider’s weight is behind the center point between the two wheels. I always pump my tires up to 120 psi in the rear, and 100 psi in the front for this reason.

A figure that is often quoted as being ideal weight distribution for a racing bicycle is 55% of the weight on the rear wheel, 45% on the front. It is one of those figures that sound about right, but has anyone ever taken the time to prove that this figure is best. I certainly didn’t in all the years I built bikes.

How would you come up with such a measurement? Maybe set a bike and rider on two sets of scales. And then the weight ratio from front to rear wheel would vary from one rider to the next because of their differing physical build.

Any vehicle or moving object will hold a straight line better if the weight is towards the front. An arrow flies straight because its weight is at the front tip, if it were at the rear it would not fly straight. In the 1960s I once owned a rear engine VW Mini-Bus. It was awful to drive in a strong wind; I would be blown all over the road.

When I first started racing in the early 1950s seat angles were around 71 degrees. We sat further back and also rode with our saddles lower than today. Gearing was a lot lower, and the theory (Back then.) was in order to pedal fast a rider had to sit back.

I always questioned this because whenever I had to make a maximum effort as in sprinting for the finish line or just to bridge a gap to a break-away, I would end up sitting on the front tip of my saddle. I would see photos of other riders sprinting and they would also be in this same forward position.

“Riding the rivet” is an expression still used today when a rider is making maximum effort. It pre-dates the 1950s when saddles were real leather and actually had rivets. Riding on the front tip where the saddle is narrower had the effect of the saddle being even lower than it already was and to my way of thinking was definitely not efficient.

It was one of the reasons I started building my own frames in the late 1950s and early 1960s. It seemed to me that when I needed to go fast, my body took up a natural position that was a lot further forward that a 71 degree seat angle would allow.

Pushing the seat angle forward actually pushed the whole frame forward making a longer wheelbase. To avoid this I made the top tube shorter and used a longer handlebar stem. This put my weight out over the front wheel and I found I had a much better handling bike. It went round corners faster and descending hills at speed felt safer.

It is often said that bike riders who are good sprinters are often good at descending hills. It is sometimes speculated that their nerves of steel that allow them to mix it up shoulder to shoulder in the chaos that is a bunch sprint, makes them fearless when descending mountains at 50 mph or more.

Maybe so, but many sprinters are big guys with a lot of weight in their upper body, chest, shoulders and arms. When in a low tuck aero position this extra weight is towards the front making bike and rider much more stable.

I have written here about “Shimmy” or speed wobble. It is a subject that gets discussed over and over on forums all over the world. It has occurred to me that these bikes with the shimmy problem are often the same well known brand of bikes that the pros use in the Grand Tours and other races throughout the season.

None of the pros experience speed wobbles, there would sure to be a video of it if they did, especially if they crashed. It has occurred to me that the fault is not with the bike, it is with the rider, and the way they have their bike set up. Or rather the way they position themselves when descending.

The pros have their bikes set with the bars set low in relation the saddle. Their weight is therefore more over the front wheel, especially when in a low tuck aero position.

If a person buys this same bike and sets it up in a more upright position because his physical limitations do not allow him to ride like a pro. They should then accept the limitations in the design of the bike which after all is designed as a racing bicycle, and if it develops a speed wobble at 45 mph. the rider should consider either a change of position or keep the speed below 45.

You will notice the pros descend by moving forward on the saddle, or sometimes squatting down on the top tube in front of the saddle, then rest their chest on the handlebars. This not only reduces their frontal area, but it places much of their weight over the front wheel. Therein lays a clue.

While descending you may not feel safe or comfortable going to the extreme of some of the riders in the picture above. But don’t go to the other extreme of the “Old Skool” position shown at the top. Study the picture, most of the rider’s weight is behind the bottom bracket, this is just asking for shimmy to develop.

Descending with your butt hanging off the back of the saddle is good for Mountain Bikes or Cyclo-Cross, because if you hit a bump or your front wheel drops on a hole, you could be thrown over the handlebars. However, on a smooth road at high speed this is unlikely to happen.  

Move forward, lower your back and try to position most of your weight ahead of the Bottom bracket. If you achieve at least a 50/50 weight distribution you will be less likely to encounter the dreaded speed wobble.