One area of the bicycle that seems to be overlooked when it comes to equipment performance is friction; especially in chain drives and derailleur gears.
From an engineering standpoint the derailleur gear is an inefficient system. However, since its invention in France in the 1920s, no one has come up with anything better.
The system of a chain drive running out of alignment on multiple sprockets is not used on any other application except a bicycle as far as I know.
When the chain is not pulling in a straight line, there is extra fiction on the side plates and the bearing pins of the chain. There is also friction on the sides of the teeth on the chainwheel and rear sprocket.
When a chain is in alignment there is only slight friction on the bearing pins as the chain goes around the top portion of the rear sprocket and chainwheel. There is little or no friction on the side plates of the chain.
One thing a person notices the first time they ride a single speed fixed gear bike, is the smoothness of the transmission and the lack of friction. This is because the chain is in alignment, and there are no pulleys the chain has to run around.
The pulleys on the rear derailleur are the other source of friction; there is the friction of the pulleys themselves, and the chain has to go around a constant "S" curve. Turning the links of the chain, first in one direction, the other.
One derailleur popular in the 1930s and 1940s was the Osgear. (Left.) It had chain tensioning arm with a single pulley just under and slightly behind the chainwheel.
This meant the chain ran in the same direction and was not made to go around an "S" curve; there was also one pulley instead of two. At that time freewheels only came in 3 and 4 speed.
The Osgear had its shortcomings; it would not work with a double chainwheel because the tension arm was fixed. However, had it pivoted on a simple ball joint and had sideways movement, it would have aligned itself as the chain switched from one ring to the next.
The other drawback was, the fork that shifted the chain on the rear sprockets was over simplistic and shifting was not that good. Had it been designed like a modern front derailleur it probably would have worked much better.
A modern front derailleur is very efficient in that it will shift the chain over a ten teeth span or more, and once it has shifted the chain it is no longer in contact with the shifter and so causes no friction.
The Osgear had fell out of favor by the 1950s when the French made Simplex and Huret derailleurs appeared; they shifted better, and worked with 5 speed freewheels and double chainwheels. The Simplex and Huret rear derailleur had the chain wrapped around two pulleys in the "S" fashion; the way all modern rear derailleurs are designed today. I do feel the Osgear was a very efficient design that was never fully developed.
Campagnolo’s Cambio Corsa derailleur (Below.) patented in the 1930s but developed in the 1940 was a masterpiece of engineering for its time, but extremely difficult to use. A long lever released the quick-release, the wheel moved forward on a rack built into the frame’s rear dropout thereby loosening the chain. Another lever shifted gear while back-pedaling. At the same time, the wheel moved back tightening the chain, and the quick-release was re-tightened. There were no pulleys to tension the chain, so no friction.
Was the Cambio Corsa developed to its full potential? Has anyone ever experimented with sprockets that slide sideways on the rear hub so the chain is always in alignment? It would not be necessary for the hub to be wider, or the rear wheel dished more; the hub could be large enough for the sprockets to slide inside. Another idea, fixed rear sprockets, and a chainwheel that freewheels, gears could be shifted while coasting.
If the chain is to remain out of alignment, how about a chain with spherical rollers at each joint so it will run out of alignment without the friction of the side plates. I know all these ideas will cost more, but with the price of the top of the line bike what it is today, what is a couple of hundred dollars more for a drive train with less friction that will allow a rider to go faster.
The derailleur gear has remained basically the same for over fifty years; all improvements have been in shifting and the number of gears. Friction is overlooked because you can’t see it; and if everyone is using the same design equipment it is not an issue.
In some of my recent posts I have waxed nostalgic and longed for simpler times. I am not against change if it benefits the bicycle and the cyclist. Many changes I see benefit the manufacturer, and then sold to the consumer after the fact.
I am just throwing out a few off the wall ideas that may or may not be practical, but would it hurt one of the manufacturers to put a little money into some research and development to find out just how much of the rider’s energy is wasted overcoming friction?
A bike store owner told me recently told me of a young customer in his store looking at a 1980s vintage steel bike that was in for a service. He pointed to the lugs and asked the store owner, “What are these for?”
I find it amazing that a method of building bicycles can be around for over a 100 years, and become lost to a new generation in ten years or so.
Since the bicycle’s invention in the late 1800s the traditional way to join steel tubes to make a bicycle frame was by melting brass into a lugged joint. Similar in a way to a plumber joining copper pipe by sliding the pipe into a pipefitting, heating, and filling the joint with solder.
Brazing, as it is known, done at a higher temperature and the resulting joint is much stronger. Early lugs were in fact pipefittings; these were heavy steel sand castings, cut square at the edges, and machined on the inside to fit the tube.
As steel tubing for bicycles became thinner and lighter, it was found the tube would sometimes break at the edge of the lug. This was because the lug was far stronger than the tube.
In any structure, if you make a joint far stronger than the parent material, the material will fail during stress, immediately adjacent to the joint. Framebuilders started filing the lugs thinner to bring the strength closer to that of the tube. For the same reason, they also started cutting the lugs into fancy shapes to eliminate the square edge of the lug.
By the 1950s the cutting and filing of lugs became the way a framebuilder would express his art and individuality. Hetchins (Left.) were one of the first to take this art to extremes.
By the 1960s and 1970s, fancy lugwork became too costly and lugs stamped from sheet steel and welded, became available. The top picture is a set of pressed steel lugs that I prepared during the 1970s, with some custom shaping a cutout work.
By the 1980s “Investment” cast lugs became available. A method developed for the aircraft industry, investment casting was achieved by first hand making a lug. From this “pattern” lug a simple plaster mould was made.
A lug made of wax was cast in the plaster mold; this in turn was coated in a ceramic material and fired in an oven. The firing hardened the ceramic coating and at the same time melted the wax from inside, leaving a void the perfect shape of a lug.
Molten steel was poured into the mold, and when cooled the ceramic mold had to be broken to remove the finished lug, hence the name, “Investment” casting. An expensive process, but the finished lug was near perfect, the tubes fit with no machining required; very little filing required from the framebuilder. Lugs, bottom bracket shells, and fork crowns are made this way.
Traditionally frames were never welded. Not because welding was not strong enough but rather the heat required to weld weakened the parent material adjacent to the weld. By the 1980s welding technology had advanced to where it could have been used to build lightweight frames. However, at the time customers, connoisseurs of the lugged frame would not accept it.
This changed during the “death” of the road bike in the early 1990s. Mountain bike manufactures could get away with the quicker and cheaper welding process, because the MTB was new and there were not the old standards, and traditions to break down. There was a whole new generation who grew up with welded BMX bikes.
When the road bike was reborn, sadly, for some of us it was an ugly bastard. Its gene pool contaminated by MTB and BMX, the beauty, style and class bred out of it. A well, that is I suppose the price we pay for progress.
My last post about the terminally hip fixie crowd was an attempt at humor. If a person tells a joke then has to explain it, it is not funny.
If a certain reader of my last post can’t tell it is satire without me labeling as such, then maybe you should get to know my style of writing before rushing to judgment.
If you think I am prejudiced against this or that cycling faction you are wrong, and the problem is not mine, but your inability to laugh at yourself.
There are people in this world who would kill us because we don’t hold their particular religious beliefs or values. We make fun of them, not because we are prejudiced, but because we see the absurdity, the humor in it.
My recent post, Womankind, and the website I was reviewing, Copenhagen Girls on Bikes, is still drawing criticism for being sexist and perverted when I intended it to be a tribute to the grace and beauty of women.
When a woman (or a man for that matter.) dresses in nice clothes, they are making the world, their environment, more beautiful.
However, I am not supposed to look and admire without the accusation of being some kind of pervert. Maybe women should dress in long black robes from head to toe, that way we wouldn’t be tempted to look.
And maybe the fixie crowd should not post pictures of their bikes and videos of their trackstand competitions on line; so the rest of us will not be tempted to make fun of them.
Label: This is a rant.
I came across a website for “Fast Boy Fenders,” an enterprise that makes beautifully crafted wooden fenders for that terminally hip crowd, the fixed gear enthusiast.
The main selling point for this item is stated like this:
“Been wondering what to do with that hole in your frame where your rear brake used to be?”
One would think the main selling point for fenders would be that they keep rain water from spraying up your back, but not these fenders. These are works of pure art, and at $75 for a small rear fender, the last thing you would want, would be to get them wet.
There is an extreme shortage of old steel track frames. They were only a small part of most framebuilder’s production; I only made a handful. Most fixed gear exponents are using road frames, which brings up the question, what to do with all the superfluous braze-ons?
You definitely don’t want to cut them off, because this will devalue the frame, and when this craze is over, probably around next spring, you will be selling off the frame, or converting it back to a road bike.
It occurred to me that a whole cottage industry could spring up, making all kinds of cool shit to hang on your bike.
The top tube pad (Left.) already covers up the cable eyelets on the top tube, so we don’t have to worry about them. Here are some other ideas I had:
The rear derailleur hanger:
The first thing that came to mind was a kickstand. However, I dismissed this idea immediately as not being hip enough. Then I thought, why not use it to hold a bolt-on rear sprocket guard? Why would you need a rear sprocket guard? It doesn’t matter why, it would be such a cool thing to have.
There is no apparent reason to have a top tube pad, but ask any fixie enthusiast and he will give you at least three good ones. Part of the fun would be coming up with a reason to have a rear sprocket guard.
The down tube gear lever braze-ons:
How about two cup shaped knee pads that bolt on to the lever bosses? When you are doing one of those nose on the front wheel stops, just lock your knee into one of these pads and it will stop you quicker than Brittney Spears singing career.
The water bottle braze-ons:
This one was a little tricky. Maybe a bolt-on card holder for those who have aero wheels and can’t put the cards in the spokes?
So there you have it, just a few starter ideas; I’m sure you can come up with others.
My apologies to Bike Snob NYC, who has made a blogging career out of lambasting the fixie crowd; I didn’t mean to steal your thunder. (Your concept maybe, but definitely not your thunder.) If a person is going to steal ideas, then steal from the best is my motto.
My adopted home city, Charleston, South Carolina is a wonderful place steeped in history, culture, and art.
I number amongst my friends and acquaintances many talented writers and songwriters.
The South Carolina state auto license plate has the slogan, “Smiling faces, beautiful places.” One of the things that struck me about Charleston in the almost six years that I have been here is the friendliness of the people.
Complete strangers will strike up a conversation with you. I have found in other parts of the world, and even in parts of the US, to speak to a stranger is viewed with suspicion. People who talk to strangers are looked on as some kind of loony person. Here I will rarely pass a stranger without at least a smile or simple greeting exchanged.
However, having made that statement, when Carolinians get in their cars it is a whole different story. Columbia, the state capital, had the dubious title earlier this year of having the worst drivers in the US. Friendly smiles and simple greetings are often replaced with a great deal of horn blowing.
So, it was with extreme pleasure I read this week that Spartanburg, SC had become the first city in this state to be awarded the prestigious League of American Bicyclists Bicycle Friendly status.
The League of American Bicyclists, founded in 1880 before the use of automobiles was widespread, was instrumental in getting paved roads established. The same paved road that most drivers enjoy and take for granted today. The same roads a few begrudgingly share with those of us who still like to ride a bicycle.
Spartanburg has become only one of twenty-four cities in the US to receive this honor; they have done so in a relatively short time. Their Bicycle Initiative Program was started in 2004 with a grant of $104,000.
Charleston take note. If ever a city could use a Bicycle Initiative this is one, with the downtown parking and congestion problems. What better way for a visitor to view our historic city than by a leisurely ride on a bicycle?
Two things go hand in hand; there is a need to get rid of the congestion to make it possible to ride a bicycle on the narrow downtown streets. More bicycles mean less cars, easing the congestion.