Hot Stems

Since I wrote about how sexy the "droopy 7" stems that fit old style threaded headsets are, and how difficult it is to raise the handle bar height on a modern bike with a threadless headset, I've been seeing things like these.

Which only proves I was right in the first place.

(shop here)

Cool Bikes at Work.

I work in a big organisation on a campus spread across a number of buildings. I have a single office in a small peripheral building, so when I'm at work that's where my bike is. But a lot of people work in shared spaces or public areas and leave their machines in the bike parking area under the overhang of the main building. I often take the chance to walk through and see what other people are riding.

All bikes are cool, but these two were cool enough to stop and take a picture. I only saw them once each, so maybe they were visitors, or maybe these are what someone was riding while their other bike was in the shop.

This one has the unmistakable Raleigh head tube badge. The labels say "Picnica by Bridgestone". Google says that's a seriously cool piece of retro kitch. A small wheel, folding bicycle sold through the 1980s, with a belt drive, popular predominantly in Japan.

The helmet tells the rest of the story.

This one is practically brand new. The 26" wheels and the geometry remind of the old school mountain bikes I used to ride. The leather saddle with large copper rivets, the comfy commuter hand grips set in an insanely low riding position, says he's a real rider's rider. (It has to be a boy.) Unfinished alloy frame, thoroughly modern hardware, fixed single-speed drivetrain and a single, front disc brake with a big, pink rotor guard built into the fork. The light, plastic mud guard is Dutch. Maxpowercycles is a German maker of polo specific bike frames. See if you can mail order one.

1994 TREK 5500 OLCV: It's all down hill from here.

My passion for cycling had been rekindled by a jellybean single speed my wife bought me online. I tinkered with the drive train to make a two speed dingle bike. Having got the bug, I rebuilt a 1970's ten speed racer, like the one I used to ride to school.

I'd convinced a couple of friends to go riding with me, but it turned out they were fitter and stronger and lighter and better riders than me. Rather than resort to training or diet, obviously I needed a better bike, or at least a lighter one.

For $9,900 I could be on a new pinarello dogma, or I could get a second hand alloy framed malvern star on bikeexchange.com.au for $399 that would do the job quite well, with a carbon fork!

But my heart said TREK 5500 OCLV (1994)...

In 1994 I was living on a Mongoose IBOC rigid mountain bike, and discovering professional cycling and the Tour de France in nightly 30min highlight packages on SBS.

Coincidentally, the years of my mid twenties coincided with the peak era of human culture and technology. Did that happen to you too? From there it has been a long slow decline into chaos and this bike is part of the story of that decline. This was Lance Armstrong's bike.

You can read the history of the OLCV frameset here, and a lot more TREK history here but basically the company started building carbon frames using the "Optimum Compaction, Low Void" technique in 1992, they built my bike in 1994, they signed up Lance Armstrong in 1997, he had the fastest time in the 1999 Tour de France and from that year, there is a 7 year gap in the official records with the competition being judged so corrupt, that no winner could be declared. For almost all of that time, apart from some changes to the forks and steerer, and tweaking the carbon recipe, Lance was riding a bike essentially identical to this one.

Lance Armstrong had a lot of fans once, but I was never one of them. It wasn't the drugs and the blood transfusions I objected to, it was the bullying and the bad sportsmanship, the corruption and the ruthless pursuit of winning without any consideration of grace or style. I miss Marco Pantani. He was the last rider to win the Tour de France before it sucummbed to Armstrong's relentless grind. His 1998 win may or may not have been done "without assistance", but it was done with style. Having prevailed in the Giro D'Italaia that year, Pantani started the Tour 4 minutes behind after the opening time trial, by the end of the Tour he had turned that into a 4 minute lead by his audacious and agressive riding in the mountains. Sadly, having been caught up in the doping scandles that followed, he died with a cocaine overdose in 2004.

In my memory the 1990s was an ideological battle ground, a fine-de-siecle struggle between different visions of how an individual might exercise personal freedom and power in the new millenium. The conflict between de-regulation and anarchy?

 

 If Lance Armstong was the Gordon Gekko "greed is good" face of the 90's in cycling, then Marco "Il_Pirata" Pantani was a fire starter... a twisted fire starter.

In this video from the 2000 Tour de France, Pantani now in the late part of his career, has caught Armstong's leading group at the bottom of Mt. Ventoux and attacked several times, starting to break away when Armstrong responds. They set a blistering pace, up the climb as they swap leads and a few words (racing without helmets). Did Armstrong pull up at the end and give Pantani the stage victory? Whatever he meant by it, Pantani found him offensive! He withdrew later in that Tour and never rode it again.

You can see a longer version of Armstrong and Pantani on Mt. Ventoux, with commentary in Italian at http://www.youtube.com/watch?v=_bMBTRqctF0.


In 1994 this TREK 5500 cost $4,500 and the old man I bought it from had been a younger man, pretty serious about his triathlons. The bike was well looked after while it was ridden and was in good condition except for the tyres and a few spots of rust on some bolt heads. It had a full Shimano 600 "tricolor" group of components, including head set and hubs built onto italian Ambrosio rims.

The 5500 OCLV was one of the first bikes with a monocoque carbon fibre frame. Carbon fibre compounds are nearly ideal materials to make bicycle frames. Their high tensile strength, low density and  stiffness (low Young's modulus) makes performance bikes significantly lighter than any other material. It's the ideal material for a bike that you are actually riding, but because of it's brittleness and vulnerability to direct impact it probably isn't the ideal material for a bike that you are trying to take apart and pack into the back of a small car, or the ideal material for a bike that you are locking up and leaving out in the street overnight, or banging around in a crowded home workshop. (Put the spanner down before you pick up the frame.) When it does break the failure tends to be sudden and catastrophic, so it's certainly not the ideal material for a bike that you are crashing, or trying to fix afterwards and get back on the road, but for riding fast and hanging on a hook in the garage it was the right choice. I believe some people would get a second hand carbon frame xray'd to look for hidden cracks. I looked the old man in the eye and believed that he'd never crashed it.

Early carbon fibre bikes were made from pre-formed carbon fibre tubes glued into alloy lugs. This Alan frame is a particularly beautiful example. It's got an alloy right chain stay, where impact from the drive train can cause damage, and alloy forks. (As opposed to the later trend for alloy frames with carbon forks.)

The OCLV frames were built in one piece in a mould and compressed from the inside with an air filled bladder. That saves more weight and allows more variations in the geometry and the thickness and composition of the materials in different parts of the frame. You can make shapes like this...

Just about everything on the bike: gears, brakes, cranks, rims and headset, is marked SHIMANO 600, mostly with a three coloured rectangle. 

Shimano make about half of all bicycle components sold and their marketing strategies are as well developed as their engineering. They cover the whole market from children's bikes to the top of professional racing, with multiple product lines and yearly model upgrades. This version is sometimes nick named the "600 tricolor group". Sheldonbrown.com tells me that the 600 group was later designated "Ultegra" and was the second level of road bike components below "Dura Ace".

I'm not sure if that necessarily means the high level group is better. It may be lighter and more race worthy, but not always as robust and long wearing, or easily adjustable and servicable.

There are bicycle enthusiasts who know much, much more about these things than I do, and they have on line forums. One of the boffins here says:

"This is one of my favourite groups of all time as it is well made, shifts extremely well, and is rather tough to boot."

In the early 90's combined brake lever / shifters (brifters), like this STI system were a signifiacnt innovation in bicycle controls. In these early models, the gear cable comes out sideways. Modern ones have it hidden under the bar tape along with the brake cables for improved aerodynamics, but otherwise they function much the same. They are more complex than the simple levers that came before them, and unlike most bicycle innovations, they are heavier. Armstrong is said to have had a climbing bike set up with a brifter for the rear derailleur for quick shifting and a simple down tube shifter for the front, to save weight. Repair and servicing are a problem. There is probably more chance of repairing early models than later ones. The manufacturers would be happy for you to purchase a new set when the old ones stop functioning.

Mine were not shifting smoothly when I got them. I did a bit of reading on line, and as advised, put a can of spray oil in all the openings I could find and repeatedly worked the mechanism back and forth. Now they are perfect every time. 

It took a bit of fiddling to get the gear cables the right length for the index shifting to work. My old mountain bike had Deore XT thumb shifters with index shifting. They were fitted with a little mechanical switch that would disengage it. When the cable stretched and the gears went out of alignment, I just turned the index shifting off.

The TREK has this Trim Tab on the down tube. You can adjust the rear derailleur cable while you're riding!

 

A sealed cartridge bottom bracket with a square taper crank fitting means I already have the tools I need for servicing, it's compatible with just about everything, and it can be easily replaced if I have any trouble with it. I assume this one is about 20 years old, and it still works alright. Modern bikes can have a variety of mutually incompatible bottom bracket / crank systems with, arguably, very little performance improvement except for some ultra lightweight, or extra strong off road applications. With the old square taper fittings, you have to tighten the crank bolts from time to time or they'll squeak, or you can wait till they squeak and then tighten them.

Eight rear sprockets is enough really... isn't it? It's a question of range versus gradation.

Look at these pedals! 

Clipless pedals, confusingly, are the ones you clip in and out of. They replaced cage-like toe clips and straps (which are still commonly used by track riders to bind their shoes to the pedals). These LOOK pedals quickly became the standard, and essentially still are, although the design is out of patent. The latest models are a bit lighter.

The coolest thing about these ones is that they are labelled D for right and G for left. They are French.

The other common type of clipless pedal is the SPD system (on the right).

These are more commonly used on mountain bikes, and by tourers and commuters, because the smaller cleat can be recessed into the sole of the shoe to make walking easier.

I found some LOOK compatible cleats that fit my old MTB shoes. It looks a bit weird but it does work.  It feels like the larger contact area helps transfer power to the pedals and I never accidentally pull my foot out, like I sometimes do with the smaller cleats, but I can't walk properly in them.

The old man I bought the bike from was a giant. He had the seat way up and the handle bars low and extended out the front on a long stem. I was a bit worried that the bike might be too big for me. It was advertised as 62cm, that's the length of the seat tube up from the bottom bracket. That is the right size for me, using the old Cinelli formula of 32 to 34 cm less than the height of the rider's femoral head. But bicycle sizing and fitting is a complex and controversial art. Sheldon Brown knows everything and says that the top tube length is the most important dimension in getting a good fit.

It was raining when I went to look at the bike.  I didn't even try to ride it but I measured it up and decided I could get it to fit me. I hadn't anticipated how far forward the natural hand position on the brifters is, but by fitting a short stem and a pair of modern compact handle bars (deisgned for Rapid Hand Movement) I managed to get everything back into a relaxed version of my early 90s riding position.

The problem with going for a smaller frame would be getting the handle bars up high enough to be comfortable, especially for an old man buying a second hand bike. I'm 45, I'm not as flexible as I was and I want my handlebars and my saddle pretty much at the same height.

The Japanese company Dia-Compe patented their Aheadset® threadless headset in 1990 and they gradually became the standard for almost all bikes.

This bike has an older style threaded headset. You adjust the height by unscrewing the bolt on top (NOT the big nut around the bottom of the stem!) and sliding the stem up and down.

With this style headset, if you can find a stem with a long enough vertical quill section, you can extend the handle bars up as far as you  like...

which is why you still see them on kids bikes and upright cruisers.

With a threadless headset, you can adjust handle bar position by fitting a different size or angled clamp on stem. If you want extra hight, you need to install a set of forks with the steerer left long, the stem position can then be set by adjusting the headset stack height with spacers or clamps. Extreme variations include this...

and this!!

(Read more about this Sheldon Brown special here.)

I don't know what sort of stress that puts on the steerer. It's normally a fairly short tube attached to the front forks and completely hidden within the bicycle frame, headset and stem hardware.

My carbon fibre forks are mounted on a steel steerer, which should bend or buckle before it breaks. In 2001, TREK changed to a lighter, aluminium alloy steerer and later to carbon fibre, both of which are more likely to suddenly snap. Want to see what it looks like when that happens? Here's George Hincape riding a TREK OCLV in the 2006 Paris - Roubaix classic... That's essentially the same bike as mine, except for the steerer and headset system.

He's putting his life on the line in the quest to sell you a better bicycle.

Some say the threadless headet is more crashworthy, with less sharp angles to impact on. The alternative theory is that the expansion wedge system holding the stem quill in the threaded headset, will give way with less force than the handle bars need to penetrate your abdomen!

I'm prepared to accept that the threadless headset system is lighter, eaisier to adjust with smaller tools, and fits a bigger range of modern handle bars than the old threaded headset. The latest development in headset technology is the integrated headset, where the bearing surfaces are part of the frame itself, instead of separate components pressed into the head tube. This is no improvement at all! (See what head set guru Chris King has to say about them.) There might be some appeal to a professional time trialist, who is looking for marginal gains in weight and aerodynamics and whose sponsor will give them a new bike for next season, but for most riders the advantage is to the manufacturer, with fewer components and assembly steps and a system that can't be effectively serviced or replaced. That means you need to get a whole new frame when the headset bearing starts to wear out.

Since the 90s, the trend (possibly influenced by mountain biking and bmx) has been towards smaller framed bikes with longer seat posts, sometimes angled top tubes, and stems that slope up from the top of the head tube to the handle bars. This may make the frame marginally lighter and possibly stiffer. But I like the style of the old "droopy 7" quill stem. This design dates from a time when bicycles were sized much bigger, even with top tubes too high to comfortably stand over. The drop in the stem allowed the handle bars to be mounted below the level of the top tube if desired.

It's sad to see the fall of the Droopy 7 handle bar stem. It may not be as technologically advanced as it's lightweight successor, but too me it was the most beautiful and sensuous of bicycle components. When I'm bent low down over the bars, dripping with my own moisture, panting hard, with my tounge hanging out, I don't want to be looking at a stubby, over eager, clamp-on stem with a pop top, thrusting up in the air, bursting with seams and joints and exposed bolt heads.

I'd rather see the languid lines of something smooth sleek and sexy like this, enticing me to go harder and longer.

Now I'm not seriously suggesting that the 1994 TREK 5500 was the indisputable high point in bicycle development and that every thing that has come after is either a marketing gimmick or a backwards step. If someone gave me a new model Pinarello Dogma or any other high performance road bike, I wouldn't turn it down. But I think if you're looking for David Brailsford's marginal gains, you also need to think about marginal costs and opportunity costs. For less than 10% of the cost, and a few hours in the workshop, I've got a bike that comes close enough for a casual Sunday ride. At least if I can't keep up with the group I know It's my fault not the bike's. And the money I didn't spend on that bike can be spent on another bike. There are so many expensive machines on the road these days, with people upgrading, giving up, or accidentally buying the wrong size, there must be some real bargains in the second hand market.

But in the mean time, here are some more smokey back lit photos of my new 20 year old bike...

...And more of the fearsome and beautiful pirate of the 1990s, Marco Pantani.

Richard's Bicycle Book.

After I wrote a post about books I'd been given for Christmas, a friend handed me a little collection of  1970's cycling books that her husband "thought I might be interested in". Well worn paperbacks, read and re-read with underlinings and annotations.

 "Closed-minded predictions that an optimum level of excellence has been reached in any field usually are soon reversed by wide-ranging human ingenuity. However, as of now the butted steel-tubed bike of standard diamond shape, brazed together with lugs,... is going to be hard to beat."

This slim collection of essays tells you every thing you would have wanted to know about bicycle frames in 1975, and a list of "currently active" US frame builders, compiled by "Bike World" magazine.

This one is a little less intense and is built around interviews with notable frame builders from around the world.

It's great if you want to know what Cino Cinelli though would be the racing bicycle of the future (26inch wheels, 180-185mm cranks, high bottom bracket and steep frame angles), or who did all the brazing at SCHWINN (Lucille and Wanda). There's always some dodgy advice of course...

"Never allow the tip of the saddle to be lower than the back of the saddle."

Certainly this guy disagrees, and he wrote the book...

Before there was sheldonbrown.com, there was "Richard's Bicycle Book". Richard was the son of publishers Ian and Betty Balantine of Balantine Books. I like to imagine his doting parents indulging their son's eccentric vanity project ... "we'll think of a proper name for it later"... only to be amazed when it turns into a classic, continuously selling, revised and updated since 1972.

It might not have been like that at all of course.

With two volumes in one, Book Two is a beautifully written guide to maintenance and repair featuring amazingly clear exploded diagrams of old derailleurs. Book One is a bunch of other stuff: history, tips, advice and opinion, featuring notorious and alarming instructions on how to kill a dog... "If this is too stark, then skip this section."

"Richard's Bicycle Book" has been updated several times and the current version "Richard's 21st Century Bicycle Book" is available everywhere. Ballantine was a notable cycling advocate, chair of the World Human Powered Vehicle Association, populariser of early mountain bikes and promoter of a certain style of assertive urban cycling that he called "traffic jamming". Enough good work to excuse that beard and jumper!

Sadly Richard Balantine passed away this week aged 72, survived by his wife, three children, two grand children and his mother Betty.

VALE, 29 May 2013.

Book Learning

There's nothing wrong with having obsessions. One of the good things about devoting every spare moment to thinking about bicycles, is that it makes you easy to buy presents for. Last Christmas I got two cycling books, along with a collection of shirts and bells and neat repair kits.

One was Tyler Hamilton and Daniel Coyle's "The Secret Race".

The other one was "Bicycling Science 3rd edition" by David Wilson with Jim Papadopoulos.

"The Secret Race" is Tyler Hamilton's story of professional racing in the European grand tours, his involvement with doping and Lance Armstrong. It's an approachable and easy book written to appeal to  cycling fans and released to pick up on the news interest in Armstrong's doping admissions and withdrawl from competition.

"Bicycling Science" is a very dense 476 pages, full of graphs, equations and diagrams, with notes and references, that just scratches the surface of the most obsessive obsessions of obsessive bike obsessives. It took a bit longer to read.

I've been reading and thinking and reading a bit more. I've learned quite a lot and I've come up with four big ideas that I'm going to try to explain here.



Bicycles are excellent for testing Human Physiology.

A bicycle is an excellent machine for transforming human muscular effort into smooth rotary motion which is easily used to drive machinery and easily measured and recorded. It can be adapted to different body sizes and shapes. It doesn't require any great gymnastic ability or highly complex skill for it's basic operation (although racing down hill in the rain is a different thing). The pattern of alternating effort and rest is said to closely match the optimum for human muscle function and it can be geared to suit different inputs and resistances.

Cycling is not a test of strength, it is a test of power. Not how much force can be applied but how fast energy can be produced and work can be done. "Bicycling Science" devotes 106 pages to discussing human power generation, including an interesting discussion about whether V02max (maximum rate of oxygen uptake), is as good a measurement of fitness as OBLA (onset of blood lactate accumulation). It then takes another 50 pages to explore the relationship between power and speed. But I think Luigi Cecchini, one of Tyler Hamilton's trainers quoted in "The Secret Race" sums up the human part of the cycling equation quite neatly.

"To win the Tour, you need only three qualities.

1. You have to be very, very fit
2. You have to be very, very skinny.
3. You have to keep your hematocrit up."

The first two are products of innate physiology, training and diet. The third is where erythropoietin (EPO) and blood doping (collecting and re-infusing your own blood) come in. Interestingly, Hamilton maintains that prior to EPO, doping in cycling was not particularly advantageous. Steroids might increase strength and aid healing but they didn't really make riders "very, very fit". Amphetamines helped overcome fatigue, but clouded riders judgement and made them reckless. EPO and blood transfusions made such a difference that no one could win without using them... well that's what the guys who were using them keep telling us.

It's also interesting that with all those years of experience, and the help of a co author and presumably editors and fact checkers involved in publishing his book, Hamilton is still slightly unclear about exactly what EPO does. He describes it as stimulating the kidneys to produce more red blood cells. In fact EPO is a naturally occurring hormone which is produced in the kidneys and stimulates red blood cell production in the bone marrow. Not a serious inaccuracy, but interesting. Perhaps it illustrates that the guinea pigs are not the ones who are running the experiment.

Bicycles are difficult to stop, but they practically steer themselves.

There are a bewildering array of different brakes on bicycles. Some will barely slow the bike down, some will lock up a wheel in an instant and possibly even rip it out of the forks. There are a bunch of difficulties in building a bicycle brake including heat dissipation through light weight components, problems of force transmission through cables and the frictional properties of materials.

I learnt that the coefficient of friction between steel wheel rims and rubber brake blocks can drop by over 90% in the wet, but with aluminium alloy rims the drop is only around 20%. This explains my childhood memory of frightening brake failure when riding my new ten-speed racer in the rain and why these days, even the cheapest bicycles have alloy rims.

But the real problem in stopping a bicycle is not stopping the wheels from rotating. The dynamics of the two wheeler mean that decelerating at more than about 0.5g (4.9m/s/s) tends to lift the rear wheel off the road making the machine uncontrollable. The authors of "Bicycling Science predict that a crouched rider will go over the handle bars or "take a header". On a mountain bike or BMX you can improve the situation somewhat by shifting your weight low and behind the saddle but the problem is still there.

In my days as an urban mountain bike rider, I lived at the bottom of Derby street, a steep hill with a tight right hand turn above a guard rail and a small cliff. Of course there were many ways to get down the hill including straight down with as little braking as possible. One wet day I got up too much speed and found that using the brakes did nothing at all to slow me down. My rear wheel lifted up and came around beside me, leaving me travelling side-ways down the hill, just as fast as I was going before. I tried this a couple of times before I realised that I was going to have to lie the bike down and hope the friction of skin on bitumen would be enough to stop me before the guard rail. If you have to do this you should put the bike down on the left to protect the drive train... I've still got the bike, but not the shorts I was wearing. I never ride without gloves, because I work with my hands.

Riding around with shonky brakes, or no brakes at all, seems to be part of the game for some cyclists. You should watch this video featuring New York cycle couriers in brakeless, fixed gear, check point races, through traffic. It shows some specialised fixed gear speed control techniques, including dropping the bike and running away, and just not stopping at all no matter what! It also covers some of the finer points of helmet cam technique.

If bicycle braking is ruled by clear and brutal physics, steering is a mystery in the realm of magic.

In most cases, a riderless bicycle, with some momentum, will tend to stay upright and continue on a straight or even curved course. If it leans to the left, the steering falls to the left taking the wheels back under the centre of gravity, righting the bike and putting it back on course. But..."Unfortunately, the mathematics purporting to describe bicycle motion and self-stability are difficult and have not been validated experimentally, so design guidance remains highly empirical."

Putting a rider on the bike just makes things even more complex, but I think this video illustrates that staying upright is mostly just a matter of keeping moving.

We all know that a touring bike is relaxed and stable, a road bike is fast and responsive, and a track bike is twitchy and aggressive in its handling. But nobody can say exactly what these things mean, or explain exactly how to design these properties into a bicycle.

There may be expert frame builders who can adjust trail, bottom bracket drop, chain stay length and stem size to give you a bike that handles just the way you want, but the "Bicycling Science" guys maintain that "Human observers are notoriously suggestible. When told that a given bicycle is special for some reason, they easily convince themselves that it is. ... in blind testing of bicycle characteristics, riders could not demonstrate anywhere near the powers of discrimination among alternatives that they claim to possess." They speculate "that many 'performance' sensations are imagined"!

The sudden occurrence of "steering shimmy" or "death wobbles" reminds me of the sort of state changes found in non-linear dynamics "chaos theory" or fluid physics, turbulent flow, two notoriously difficult areas where apparently simple deterministic systems can display unpredictable behaviour.



There are only three things slowing you down and only two together at any one time.

I'm quite interested in how to go fast.

On a smooth road, pedalling with constant power, there are three forces limiting your speed. Air resistance, slope resistance (gravity acting down hill) and rolling resistance.

Air resistance is pretty simple to understand. The faster you go, the harder the wind blows back on you. If you crouch down out of the wind, you can go a bit faster. I hate to admit it, but wearing tight fitting, lycra probably does make a difference to your potential top speed, at least compared to something like this...

If you really want to get aero dynamic of course you have to go recumbent. You could even go for a full fairing, maybe with a small electric fan creating suction, to prevent boundary layer separation at the tail.

Interestingly in a fully enclosed bicycle, or a stationary cycle, the loss of the cooling effect of air movement over the rider significantly reduces the maximum power output that can be achieved.

Air resistance is a very significant factor in limiting a cyclist's top speed, racers put a lot of effort into equipment and riding techniques that reduce aerodynamic drag, but it is only a significant force at high speeds.

At slow speeds, climbing hills, slope resistance is a more important limiting factor. This is also a pretty easy force to understand. It's gravity. The steeper the slope, the more it slows you down, and the heavier the bike and rider, the more power is needed to lift them up the hill.

Strangely, on a flat road, weight has no direct effect in limiting your top speed. It does effect acceleration, how quickly you can get to top speed, but once you get your  momentum up, a heavy bike should go almost as fast on a flat track as a light one. (Weight does make a contribution as a determinante of rolling resistance.)

The other things that might hold your bicycle back, are energy losses in the drive train and resistance in the wheel bearings.

I was a bit disappointed, after all the time I spent cleaning, repacking and adjusting my wheel hubs, to find in "Bicycle Science" that "the drag of ordinary ball bearings is utterly negligible". Apparently, regardless of what they feel like when you turn the axle in your fingers, or spin the wheel in the air, under load, any reasonable quality ball bearing hub gives the same excellent performance. Expensive, high end hubs might look beautiful, they might weigh less, last longer and need less servicing and adjustment, but the won't actually make you go any faster at top speed.

Similarly, any reasonable pedal, crank and bottom bracket system will provide energy transfer so close to perfect, that any improvements make no real difference to performance..?

There might be some benefit from paying attention to the chain and gears. The best derailleur, chain transmissions may have efficiencies of over 99%, compared to average performances of only around 95% (wow a whole 4% difference!). A rusty chain, driving an internal geared hub might be only 85% efficient. But how much benefit is there from having a perfectly straight chain line on your fixe/single speed? "Negligible"!

That leaves rolling resistance, the resistance encountered by the wheel in contact with the road. This is all about road surfaces, wheel size and tyres..."rolling-resistance coefficients for smooth surfaces are widely accepted to range between 0.002 and 0.010, making the tires the second most important contributor, after air resistance, to the level-road drag acting on a bicycle". Reducing the coefficient by just 0.001 can increase top speed by up to 10%!

Tyres are the second most important thing for making a bike go fast! That's second after air resistance, if you're going fast, or weight if you're going up hill. But what makes the best tyre? That's a complex area full of compromises between performance and durability, empirical testing and trade secrets. Making good tyres and choosing the right tyres for the ride are mysterious arts.

While I was writing this post and thinking about how to go faster on a bicycle, I found out about Graham O'Bree. He has a diagnosis of bipolar disorder and has survived three suicide attempts. He also has two individual pursuit world championships and has broken the hour record twice. The International Cycling Union has twice changed it's rules to ban O'Bree's unorthodox riding positions and he's now making an attempt at the International Human Powered Vehicle Assosciation's land speed record, riding "The Beastie".

For Graham, it's all about aerodynamics, he's still perfecting the plastic fairing that will be sealed around him for the record attempt. The bike is made of steel, the drive train is complicated with multiple parts and the wheels are small (but with pumped up, narrow tyres). He doesn't have to ride up hill, so weight is not a big issue, he's gone for the smallest frontal area he can, tapering back to a drive system with "nothing between the ankles". As well as being aerodynamic, he believes he gets better bio-mechanical and cardio-respiratory performance in this position.

Brilliant!

Bicycles are disposable.

Bicycle frames and weight bearing components such as cranks and handlebars, don't usually break from a single high level of force that exceeds the "ultimate tensile strength" or "yield stress" of the materials they are made from. Nor do they break from "high-cycle fatigue" the accumulated effect of millions of small stresses repeated in normal riding. They break from "low cycle fatigue", failure occurring after a few, or a few thousand moderate to large stresses such as bumping off a curb, hard sprinting, or minor crashes. A standard bicycle might survive a few thousand such shocks, which could accumulate over a few decades or a few years depending on how it's ridden. You could build a bicycle that would last ten times as long, but it would weigh twice as much.

Practically every component of a bicycle faces this trade off between weight and durability. There are hundreds of parts in a bicycle and any one can break or wear out with normal use. Helpfully, most bicycles are built with fairly standard components, so parts can be easily replaced and even mixed and matched from different manufacturers, and the bike can be constantly repaired and renewed like "grandpa's axe". Less helpfully, there are more than a few different standards, often originating in different countries at different times, so your old italian frame may not fit a new japanese bottom bracket. There is also the contrary design strategy, where components are made with unique compatibilities and even requiring special tools to fit and adjust. This might be dictated by particular  aspects of the design, but also as a marketing strategy, tying customers in to a particular brand.

Cycle racers need machines that will last for 300km of hard riding, but then the team mechanic can completely re-build the bike overnight. Many bikes will take years to travel that far, but might never be fully serviced again after they are built. These are very different situations and I often wonder if ordinary riders are getting a good deal when they buy "performance" bicycles. At least for some components "performance" might mean light weight, limited life-span and impossible to service or repair.



So.

I like riding the The Dark Horse, my rebuilt 1970's 10-speed. I like the big 27" wheels. It rides pretty nicely down hill and on the flats, but I've been riding with some mates on Sunday mornings and I keep getting left behind on  the hills. So maybe I need a new bike...

Weight is important. The Dark Horse weighs an old school ton, but "Bicycling Science" tells me, adding 1kg (1-2% increase in overall mass) will only cut 30sec from an hour long climb. "Rarely enough difference to catapult a typical contestant onto the winner's podium ... only those who are already good enough to place in races have justification for weight shaving... (for) the vast majority of us ... a conventional 12-kg machine should serve well even in most competition."

It's worth noting that this book was published in 2004. It boldly states "The upshot of this discussion is that, compared to current (2003) sport bicycles, reduced weight or enhanced stiffness theoretically should offer virtually no performance advantage and may not even be detectable by the rider."

Today the UCI road racing rules set a minimum weight of 6.8kg as a safety measure... and a really fast bike looks like this...

(Shara Gillow)

That's the sort of aerodynamic styling you need to win a national time trial championship, but it's a bit extreme for a Sunday hack like me.

Being an average hack rider, I could probably loose more weight off my belly than my bicycle. 6.8kg is  less than 10% of my body wieght.

I don't need the latest race-worthy components... Electronic shifters..? I'd rather have fairly sturdy stuff, that can be serviced and adjusted easily with standard tools.

What about this 1994 Trek 5500 UCLV carbon road bike with Shimano 600 'tricolor' groupset?

It was $4500 when it was new, now $650 on bikeexchange.com.au. It's probably got a few miles left in it if I don't ride it too hard and  I can spend the money I've saved on some new tyres!