by Robert Penn
I have no immediate plans to head off on a trans-continental journey on my dream bike, and, anyway, it’s not going to be a touring bike. One day, though, I plan to do some ‘credit card touring’ on it — that’s touring with no luggage except for a wallet. I hope to be off the map on it. I’ll be in a town on a former slave-trading route at the foot of a great mountain range having the frame straightened by a bald welder with one eye, as children skip about shrieking, ‘Give one pen!’ The frame has to be steel.
We know more about steel than any other material used to build bikes. This alloy of iron and small quantities of other chemicals has been a building block of post-industrial civilization. Today, 95 per cent of all bikes are still made from steel. Most of these are made in China and India from ‘mild steel’, the cheapest, heaviest form of the alloy. If you’ve ever jumped on a bike in Asia and wondered if someone’s tied a baby elephant to the back, you’ve ridden a mild steel frame. They are very heavy.
Most of the off-the-rack bikes for sale in western countries are made from lighter, low-carbon steel, generically known as ‘hi-tensile’, or else they’re made from aluminium. ‘Hi-ten’ steel is still relatively inexpensive to produce, is durable, but is stronger than mild steel so less of it is needed to make a bicycle.
At the top of the pile are many high-quality, low-alloy steels. All quality steel bikes are made from these senior-grade, light and tremendously strong iron alloys. There are several noted marques producing steel bicycle tubing: Columbus, True Temper, Dedacciai, Tange and Ishiwata. If you’re British, though, one name resounds: Reynolds.
Alfred Milward Reynolds ran a factory making nails in Birmingham in the late nineteenth century. In his spare time, he obsessed about a problem that was then exercising the whole bike industry: how do you weld together thin, lighter-weight tubes without weakening the joints? Failure after failure led him to devise a tube with ‘ends a greater thickness than the body of the tube’, as the original 1897 patent for ‘butted tubes’ stated, but with the same diameter throughout, so saving on weight without compromising strength. It was a breakthrough for the industry. Bicycle manufacturers set about making the next generation of frames that were both strong and very light.
The Reynolds company went on to make motorcycle tubing during World War I, wing spars for Spitfire fighter planes, tubes for bazookas, wheel rims for Rolls Royces and Concorde engine parts, but this archetypal Midlands manufacturing business always returned to steel bicycle tubes. In the alchemy of designing aircraft tubing, Reynolds stumbled on a manganese-molybdenum alloy that made wonderful bikes. In 1935, the company introduced ‘531’ tubing. It was considered revolutionary. Even now, British cyclists of a certain age go misty-eyed and look away towards the horizon just at the mention of ‘531’.
For forty years, it was the benchmark of excellence in high-end frame materials. In all, twenty-seven Tour de France wins were recorded on Reynolds frames. Luminaries such as Anquetil, Merckx, Hinault, LeMond and Indurain rode bikes made from double-butted Reynolds tubes. The long association between the professional peloton and Reynolds was broken in the 1990s, however, when elite cyclists turned to carbon and titanium. But just when it looked like steel might be abandoned, Reynolds struck back.
In 2006, the company discreetly introduced ‘953’ — a lightweight stainless steel tubing for racing bikes. It has propelled steel alloy back into the premier league of tubing materials. This specially developed, low-carbon steel alloy containing nickel and chromium has superior strength, which means the tube walls can be extremely thin. It is the new benchmark, ultra-high-strength, steel alloy for bicycles. It’s also resistant to corrosion. These outstanding properties make maraging steel, the group of iron alloys to which 953 belongs, useful in diverse fields — fencing blades in foil and épée, firing pins in automatic weapons, and in centrifuges for the enrichment of uranium.
A final point about 953 is that the tubes are straight and round, or roundish. Most expensive, mass-manufactured, modern road-racing bikes have oversized aerofoil or oval-shaped, even curved, tubes. These may improve the performance of elite, professional riders. They may not. Either way, the bikes are ugly. Straight, round tubes may now be old school, but they look better.
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The Reynolds 953 tubeset was sitting in an open box on the corner of a table when I walked into Jason’s workshop. It contained top tube, down tube, seat tube, head tube, two chain stays, two seat stays, two drop-outs and a brake bridge. I held one of the main tubes in my hand and caressed it with my thumb and forefinger. Its weight and sheen gave an impression of quality. I put it carefully back in the box. Jason explained why the three main tubes were slightly different diameters and shapes, with reference to their strengths and the stress that varying forces put on the frame.
‘It’s the combination of tubes we believe is best for your bike,’ he said.
Jason was pacing about, tidying and preparing the workbenches. An elegant single-speed, hard-tail mountain bike leant against a wall. The bulbous wings and grille of an MGB sports car peaked from under a dustsheet in one corner. In another, there was a large armoury of tools: hacksaws, drills, files, wire brushes, bottom bracket taps, head tube reamers, a milling machine, pliers, spanners, ratchets and several things I didn’t recognize. In the centre of the workshop was the jig, a small piece of scaffolding that holds the tubes in place, to maintain their precise alignment while they are being welded together.
‘First, we cut the tubes roughly to length,’ Jason said, pulling one from the box and holding it up. ‘I’ve already done this. Now I’m going to mitre the ends of the tubes so they butt up perfectly . . . so there’s maximum metal contact at the joint and we get a really good weld.’
Suddenly the room was booming with a raucous, metallic noise. Orange sparks were flying out of one corner. Jason was grinding the steel tube down on a huge belt sander.
‘It doesn’t half wear the belts through fast,’ he said, pausing to check the mitre. ‘But it’s that strong this 953, you can’t use a metal cutter on it. You can’t use a lathe or a mill to do this, so we pretty much hand-built this sand-belt mitring machine. We call it “homebrew”. In the old days, when we built more traditional frames with lugs, the mitre wasn’t quite so important. But with TIG welding, it’s got to be immaculate.’
I had thought about a frame made the traditional way, using steel lugs that fit over the ends of the tubes like sockets, and join them together. From the late nineteenth century until the 1970s — most of the history of the bicycle — it was the preferred way to build high-end steel frames, largely because the lugs meant tubes could be thinner and lighter. Advances in metallurgy, as well as the introduction of TIG and MIG welding processes, have effectively negated any advantage. Today, to have a lugged frame is basically a cosmetic decision. It generally costs a bit more, too.
From the 1930s to the 1960s, British frame-builders obsessed about lugs. It was perhaps the vestige of a refined aesthetic that had prevailed among British artisans since the beginning of the Industrial Revolution. A bespoke bicycle workshop would have employed one frame-builder, a painter and the filer, who handfiled standard steel lugs into ornate objects of art. The sheer beauty of a builder’s lugs became the benchmark of his craftsmanship.
Many British builders were known for their outstanding lugged steel frames, but one marque stood out in the attempts to beautify the bicycle — Hetchins. Russian-born Hyman Hetchin fled the Revolution in 1917, aged 26, and began selling bicycles out of his north London home in the 1920s. He sold frames made by local builders, one of whom was Jack Denny. Denny believed longer lugs would make a stronger frame; and longer lugs meant more room for decoration. Denny and Hetchin also patented curly seat and chain stays. The bikes, with model names like Nulli Secundus and Magnum Opus II, were crowned with rococo ‘lugs of distinction’. Today, Hetchins frames are highly sought after by collectors, though the froufrou lugwork certainly isn’t to everyone’s taste.
The obsession
with lugs has recently crossed the Atlantic. Several of the revered American artisans making bespoke bicycles today were apprenticed in London and Milan in the 1970s. They took the ailing tradition of lug-cutting back and nursed it. The new wave of young, idealistic US frame-builders has embraced it. In Britain, you only read about lug-cutters in the obituary pages on vintage bicycle collectors’ websites.
When the firework display was over, Jason began preparing the jig. He worked quickly but there was an ease even in his hastiest movements. His hands appeared to be pre-programmed. They were often completing one job while his mind was clearly attending to the next. I wondered if this was a mark of his artisanship. It was certainly a reflection of his experience: he builds five frames a week.
When the jig was set up and the tubes clamped in place, he checked everything over, reverting one last time to the piece of paper pinned to the wall with the measurements for my frame. ‘Head 73°; Seat 74°,’ he said to himself, like an incantation.
Jason was referring to the two angles that are fundamental to the geometry of the frame: the angles of the head tube and the seat tube. The geometry of a frame — that is the angles between the tubes of a frame — is largely determined by the intended application of the bicycle. Criterium, triathlon, time trial, touring and sportive bikes are all variations of the road bike, for different purposes. They may look roughly the same shape, but in fact they each have a different geometry, giving them different ride characteristics. Mountain and commuter bikes have a different geometry again.
Frame geometry is an important factor in how a bicycle rides, how comfortable it is, how it responds to a rider’s manoeuvres, how it corners, descends and even climbs. Many other factors also affect ride quality — from the frame and fork materials to tyre pressure — but the geometry of a frame sets the parameters. Few cyclists ever think about frame geometry. If you buy a mass-manufactured bike, it’s scarcely a consideration. When I brought up the subject of frame geometry with a friend, he said: ‘Rob, just how long is your beard going to be when you’ve finished this book?’ And he’s a cyclist.
Along with the immaculate fit and the right tubing material, geometry is an intrinsic part of buying a bespoke bicycle. Get the geometry of the frame wrong and you could end up with a bike that is at best uncomfortable, and at worst, dangerous to ride. Get it right, and the bike will have the handling characteristics you desire.
Seat tube angle: measured in degrees relative to the horizontal plane (ST∠° in the diagram), they can vary from 65° to 80°. Steeper angles (75°—80°) push the rider’s weight forward on to the handlebars and are less comfortable over long distances, but more aerodynamic; they are common on dedicated time-trial bikes, track bikes and triathlon bikes with aero bars. Slack angles (65°), which place more weight on the saddle, belong on commuter or other bikes for short trips. Conventional road-racing bikes with drop handlebars tend to be between 72° and 75°. The angle is partly determined by ergonomics — that is, the saddle being in the best position for efficient pedalling. The seat tube angle on my bike is 74°.
Head tube angle: again, measured in degrees relative to the horizontal plane (HT∠° in the diagram), it has a marked effect on steering characteristics and shock absorption and can vary from 71° to 75°. Steeper angles mean a bike handles more quickly — turn your head and the bike turns too (such bikes are often described as ‘twitchy’ or ‘Italian style’ and are favoured by pro racers for criteriums — short road races round city centres, with many tight corners and a densely packed peloton). Slack angles make a bike more stable, notably on descents, and generally more comfortable over long distances. Touring bikes have slack angles. The head tube angle on my bike is 73° — bang in the middle and accepted for at least seventy years as the optimum angle for a road bike. Tour de France style bikes, sometimes known as ‘stage racing’ bikes, commonly have a head angle of around 73°: it’s sporty but sensible.
Other geometric measurements that contribute significantly to the ride characteristics of a bicycle are the wheelbase — the distance between the front and rear hubs — and the height of the bottom bracket. Both, again, affect the handling. Brian determined the geometry of my bike taking account of my physique, my experience and the type of riding I plan to do. The result will be a sportive-style bike: the handling will feel sharp, but the bike will be comfortable enough to sit on all day, and stable when I’m steaming down a mountain in the Dolomites at 45 mph.
Unless you are a very experienced rider, you’ll struggle to distinguish between two sportive-style bikes with a one-degree difference in the head-tube angle, but ride a triathlon bike and then jump on a touring bike and you get the message. Be warned though; the more you learn about geometry, the faster your beard will grow.
‘We’re ready to weld, Rob. You know you can’t observe TIG welding with the naked eye. It can burn your eyes out. It’s called “flash burn”. It’s like someone’s chucked broken glass in your eyes. Best avoided, so here’s a mask.’
The TIG process entails welding tubes directly together, in a blanket of inert gas, using a tungsten welding element. The tungsten acts as a torch, heating up the tubes and the filler metal, which is fed into the weld during the process. Originally developed in the aerospace industry, it was Californian BMX frame-builders who introduced the process to the bicycle in the early 1980s. It was a grassroots innovation that went into the mainstream very quickly.
With the mask on, I felt like Darth Vader in a village pantomime. Jason adjusted the settings on the control panel of the welder and checked the tungsten electrode. There was a great snapping sound, like a wet flag straightening in a gale, and the torch was lit. It could have been the inspiration for a light-sabre, I thought. With huge leather gloves on, and a filler rod in one hand, Jason set the torch to the tubes.
‘I’m just tacking it in first,’ he said, ‘to fix the joint. Then we’ll get rid of the clamp and weld it properly.’ The jig rotated on a horizontal axis, and Jason worked round the first joint with steady hands. When the head, seat and down tubes were welded with surgical cleanliness, he began work on the top tube: mitring, checking the tube against the frame and mitring again, over and over until he was satisfied. The front triangle was taking shape. Bare, and without stays, it looked fragile.
‘It’s too easy to blow a hole through 953, the tubing is that thin and delicate. Mistakes are very expensive,’ Jason said. ‘I have to concentrate so hard, like. That’s why I won’t have people in the workshop when I’m welding. You’re a very rare exception, Rob, and that’s only because Dad bent my ear.’
Next Jason used the jig to set the wheelbase length of the frame. ‘I’m setting the frame for a 23 mm tyre, as you agreed with Dad. The edge of your tyre will come to here,’ he said, placing a finger on the jig, a short distance behind the bottom of the seat tube, ‘but the frame will actually take any tyre from 18 to 28 mm in diameter. If you were having mudguards, or what have you, then we’d set it back here a little, but with you having pretty well a race bike, really, it’ll be here.’
Jason set to work on the chain stays, cutting them first with a hacksaw, and then shaving them down on old Homebrew. Again, it was trial and error — shave a bit, hold it up to the frame, shave a little more . . . repeat until perfect. I was amazed at how much of the work was done by eye.
‘Because no two humans are the same, no two frames are the same,’ he said, snapping the stay against the frame and the jig with a soft, metallic ‘tch-ik’. ‘I’d love to be able to pre-mitre twenty chain stays in a batch and just pop ’em in, but you can’t. Every joint has to be handmade. And that’s why it’ll only fit you right. Why it’ll be perfectly balanced, just for you.’
The seat stays were the last tubes to be welded: they would complete the rear triangle, and the diamond shape. There are several ways to affix the top of the seat stays to what is called the ‘seat cluster’ — the junction of the seat tube and the top tube. As with lugs, the method of attaching seat stays developed a
mong British and Italian frame-builders during the twentieth century, as a way of distinguishing who built the bike — it was like a signature, and a mark of the pride an artisan took in identifying himself with his work. It is the aesthetic flourish underpinned with practical design that typifies the frame-builder’s artistry.
The different methods include ‘fastback’, ‘semi-fastback’, ‘Hellenic’ and ‘wishbone’. At Rourke’s, they favour what is widely recognized as the strongest way to attach the seat stays, whereby they are mitred to wrap right around the seat cluster and rejoin above it.
‘The “wrapover” seat stay has been something of a Rourke trademark for the last 30 years,’ Jason said when he’d finished mitring. ‘I’ll be honest: it’s a right headache, but it looks great. At least, we think so.’
The torch snapped alight again. We flipped our visors down. Jason picked up a fresh filler rod and the flame roared into action on the seat cluster. He worked methodically round the weld, turning the jig, flicking the cable of the torch from beneath his feet, holding the flame steady at the exact distance from the weld. Ten minutes later, the seat stays were on. The torch went out. Jason pulled off his mask and stepped back, inviting me forward with one arm, like a midwife in a maternity ward introducing an overawed father to his child. The frame of my dream bike — the diamond soul — was finished.
2. Drop Bars, Not Bombs
Steering System
Life is like riding a bicycle. To keep your balance,
you must keep moving.
(Albert Einstein)
In April 1815 the Indonesian volcano Mount Tambora erupted, and continued doing so for three months. An estimated 90,000 people died. It remains the biggest eruption in recorded history. Millions of tons of volcanic ash were blasted into the earth’s upper atmosphere, forming an aerosol veil that shut out solar radiation across Europe and North America. The sun disappeared, rainfall increased and average temperatures fell several degrees. It is probably the most dramatic incident of global cooling the world has ever known.