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!

The Dark Horse

I bought a pig in a poke.

For $10 on eBay I got an old ten-speed racer. A big framed Graecross Capri, with a 61cm (24inch) seat post and lots of rust.

After I stripped it back to the frame it looked like this...

And when I had it prepped and powder coated it looked like this...

Nice... Lewis & Sons in Morningside do a lot of bike frames. One of the sons is a BMX fan and takes care masking all the holes in the frame and keeping the powder out of the threads.

I started planning how to rebuild it...

There were a couple of options. The main problem was the size of the rear wheel hub. I was definitely going to need a new wheel set. The old ones were rusted beyond repair, but the rear frame spacing, the gap between the rear drop outs, where the wheel hub sits, was only 120mm.

Modern derailleur geared bikes carry 10 or more rear sprockets, in a cassette that fits on a freewheeling hub with an overlock nut dimension of 130mm or more. But this 20 year old frame was build to fit a 120mm treaded hub with a 5-speed freewheel. A new set of standard road wheels was not going to fit.

I could set up the bike as a single speed / fixe, using a 120mm track hub. I tried this out using the rear wheel from my dingle bike.

But if I wanted to build a bike with gears, I really only had two choices. I could use an internal geared hub, or try to find an old style wheel set like the one the bike originally came with. 

(Sheldon Brown can tell you how to cold set, or bend a frame to fit a wider hub, so there is a third option for those brave enough.)

Luckily, the bicycle designs that were state-of-the-art in the 70s are still being manufactured in factories in Taiwan and China. This on-line bike store had a good range of the parts I needed, and I also got some from this eBay store. I went for cheap and cheerful, in keeping with the spirit of the 70s 10-speed, except maybe not the suicide brakes. 

I was going to need a new wheel set, brakes and probably gears, bars and stem, but not all the old components were beyond salvage. The bottom bracket looked like this when I got the bike...

But after I soaked them in turpentine, cleaned them up and lightly sanded off some surface rust, the bottom bracket and head set parts looked like this...

Ready to pop back in to the frame with some grease and new ball bearings.

I also chose to keep the old stem shifters, partly because I liked this bolt-on down tube cable stop that went with them.

It polished up nicely with it's shiny Shimano brand showing. I think it's chrome plated, it's flaking off a little in the corners. The main bearings themselves are more or less stainless steel, but the shifters are something else. Not as shiny, and more rust prone, after a bit of work, you could read the brand and the message PRODUCT OF SINGAPORE.

 

I'm not an expert in asian industrial history, but I remember growing up in the 70s. There was a kind of inter-generational disconnect in attitudes about asian manufactured goods. Adults would say "made in Japan" with a sneer, expecting poor quality materials and work. That may have been true in the 50's and 60's, but kids knew that in the 70's lots of cool things, electronic equipment, bicycles, sporting goods and just about every decent toy that you wanted, came from Japan. Things made in Hong Kong or Singapore, were more likely to break and were a lot cheaper.

The word kaizen was first used to refer to industrial process control in 1951, in an American sponsored management training film titled Kaizen eno Yon Dankai, "Improvement in four steps". Japanese industry, particularly Toyota, took this idea of "continuous quality improvement", spun it into a culture and sold it back to the US via Anthony Robbins and co. They also developed in to the world's second largest economy and the great industrial innovators of the late twentieth century.

My old bike's origins had been glossed over when it was sold. A sticker on the frame said that it was "manufactured for Graecross industries Aust". I think the major part of the bike, the frame and the main bearings, came from Japan, where the heavier industrial processes of casting, machining and tube drawing were established, but the shifters from Singapore, show the movement off shore of lighter cutting and forming processes, as the Japanese economy started to heat up and industries started looking to save costs on cheaper real estate and lower wages.

Over the next few decades the changes continued. Now days something made in Hong Kong or Singapore is more likely to be a complex financial derivative than a simple bicycle part, and in Korea, Kia is looking like the new Toyota and Samsung is taking over the world of electronics. Most of the cheap and cheerful new parts for my 10-speed rebuild came from Taiwan or mainland China and the quality is not bad. It may not be too many more years before cyclists are looking for high end boutique parts from Shenzhen and getting their basic components from Borneo or West Africa. (Actually your boutique carbon frame probably already comes from China. Does the label say "manufactured for...")

So here's my cheap and cheerful restoration of a circa 1970s ten speed racer....

I probably could have cleaned up the old derailleurs, but it wasn't worth the work for the price of these brand new ones.

I already had some 170mm cranks, pedals and chainrings. I think they look ok and the sizes work.

These chunky double pivot caliper brakes are not the most streamlined you can get, but they will stop the bike and the 100kg rider going downhill.

I remember Diacompe components from my childhood. The other brand that wasn't Shimano, and a bit of a step up. They invented the suicide levers the bike originally came with. Apparently they traded the design in an intellectual property deal with European brake manufacturer Weinmann and became the leading Japanese brake supplier before Shimano.

These new levers are safer and I like the look. They're not Aero!? The quick release for the brakes is in the lever!  Now made in Taiwan.

These new 27" single wall aluminium rims are built on Joy Tech hubs that look like exactly like the ones on the bike when I bought it.

I kept the old saddle and I quite like it, although it does have a few holes.

And to ward off accidents, this brass temple bell.

So I start off down the hill outside my front door and chase the middle aged men in lycra. See if I can overtake them on the outside of the down hill corner on the way to the ferry stop, or on the inside of the round about.

One of my mates from uni has come back to town from Victoria. He says he hasn't cycled much since he decided not to turn professional out of high school. He alway rode a motor bike when I knew him, but he's got his old road bike working and we've been riding loops around the river on Sunday mornings. I've found a web site that has 27" racing tyres and I'm waiting for my order to arrive.

A Pig in a Poke

I got the flu over winter. It seems to happen more now I've got small kids. And it hangs around for longer.

I got out of condition and didn't find the 52-16/18 two speed dingle bike so easy to ride anymore.

So I started thinking about a bike with gears... and I found this on ebay.

From the pictures the seller had posted I could see it was a big frame. You can see the head tube is enormous compared to tubing diameter. I liked the horizontal drop outs which could fit a single speed or hub gear option. And I liked the $9.50 I paid for it.

Obviously it needed a bit of work. Which was part of the attraction.

The expression a pig in a poke, is a warning about buying goods you can't inspect properly beforehand... clearly there was no ebay in medieval europe. I didn't really pay much attention to it, and I didn't really take a proper look at the bike till I got it back from Burpengary where I'd picked it up.

What did I find?

The stickers say Graecross Capri (with Pro-Bike apparently added later).

It was "manufactured for" Graecross Industries (Aust P/L) Bayswater Victoria 3153.

And sold by Kev OLSEN Cycles Toowoomba.

Coincidently, I grew up in Toowoomba. I don't remember Kev Olsen cycles but I do remember 6 digit phone numbers. I'm pretty sure that makes this bike nearly 20 years old at least.

The Internet doesn't know a lot about Graecross cycles. It was one of the brands acquired by Pacific Dunlop when it took over Malvern Star around 1992. There's a  blogger in Melbourne with a bit of a fetish for taking pictures of a particular step-through model. The collectors on this bike forum posted this magazine article from 1984 (I think).

Some times the groovy 70's type face is misread as Sraecross.

After looking at the various Graecrosses for sale on line, my guess is that they made low end to fairly decent road bikes in the 70's and 80's....

 (This one on flickr is probably not quite as old as mine.) 

... before the brand ended up on a range of basic mountain bikes and kids bikes in the 90's. 

 Maybe after the original company was bought out?

Mine is a "Ten-Speed Racer", I guess from the 70's or early 80's, of basic to mid-range quality. I think the "Pro-Bike" sticker is marketing, not a real sign of quality. I rode something like it in primary school but it was white, a fair bit smaller and branded "Toyosha - made by the Toyota Auto Body Company". I suspect this one was also made in Japan, the frame at least. That's what "manufactured for Graecross" probably means. The gears are Shimano Tourney, which the net says was a mid level group. The brakes say "Star Brand". The hubs are Joytech (Taiwanese) and the shifters say "Product of Singapore"(under the rust).  Sheldon Brown's articles on cable installation, freewheels, frame spacing, brake extension levers and stem shifters gave me some clues about the age of the bike. 

Look at these features.

Rear derailleur hanging from the axel not the frame.

5-speed freewheel on a threaded hub, not a multispeed cassette on a freehub.

120mm rear frame spacing. That's narrow by today's standards.

Cables above the bottom bracket. Pre-mid-80's style.

Stem shifters, late 70's early 80's. Threaded headset. (Rust.)

"Suicide" brake lever extensions. Another 70's feature for riding a "racing" bike in an upright position. These days you can get interrupters which have the advantage of actually working to apply the brakes.

"27 inch" steel wheels (rusty), with axle nuts not quick release.

The spokes are broken but the tyre is still holding air!

Straight seat post with a clamp. Vinyl covered plastic saddle.

Brakes (basic single pivot side pull callipers with cable adjusters but not quick release) and reflectors and rust.

Cotterless cranks with a "pie plate"chain guard (and lots of rust).

Cup and cone bottom bracket not a cartridge (with even more rust).

The frame was OK but most of the gear looked like it would have to be replaced... if I could get it off! And I wasn't really sure if I could get new parts that would work, especially with the narrow rear drop out spacing. Maybe I had bitten off more than I could chew.

So I got out the angle grinder!

I needed that to cut the chain and get the old kick stand off... which I managed to do without cutting the frame. But then everything else came apart fairly easily with some basic tools and a bit of muscle. Maybe a sign that the components weren't too poor quality, some of them at least. The head set races came out with a few taps from a hammer and steel bar. And the frame was stripped ready to be painted.

In the mean time I started planning how I was going to rebuild it.

More later.