Roberts Cycles, 89 Gloucester Road, Croydon, Surrey CR0 2DN, England
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ROB PENN ON ROBERTS AND WHY STEEL IS REAL
STEEL IS REAL
There were few sure things about this bicycle from the outset, but one of them was the frame material: steel. It's been the backbone of the bicycle for over a century. Until the mid-1970s, it was the only real option. Even in the early 1990s, the majority of high-quality bikes still had steel frames. Today there are many materials on the market: aluminium, titanium and carbon-fibre-reinforced polymers are common, but you might prefer your personalised steed to be made from moulded plastic, magnesium, beryllium (a toxic chemical element found in minerals and used in rocket nozzles), hemp, wood and bamboo. In fact, bamboo is emerging as the new material of choice for socially entrepreneurial frame-building projects in Africa, though it was first used to make bicycles a century ago.
I've tried all the major frame materials. I've had aluminium road bikes with carbon forks, steel mountain bikes, aluminium mountain bikes, a steel touring bike, a titanium road bike, a full-carbon road bike and an aluminium mountain bike with carbon seat stays. So which material, or combination, provides the best overall ride? I have my opinions on all the bikes I've had but I know they are affected by my personal experiences riding them: how long I had the bike, where I rode it, who I rode with. Objectively, I'd be pushed to say which material provides the best overall ride. I know from reading about it that frame materials do have different properties: in fact, some people eulogise profusely about the 'ride characteristics' of this material over that. I'm not so sure. Such things are very subtle, and only measurable with sensitive engineering instruments.
There is much nonsense passing as wisdom about materials for bike frames. The reality is that a good bike builder can make a good frame out of any of the materials mentioned, with any desired ride qualities: if the diameter of the tubes,the thickness of the tube walls and the geometry of the frame are right, the bike will be right.
The poppycock really piles up when people talk about the stiffness of a particular frame material: this property of a material is measured by something called Young's modulus or elastic modulus. A stiff frame transmits the impact of every pebble and nick in the tarmac directly to the nerves in your gluteus maxims, that is, your bum, while a flexible frame absorbs the shocks. Most people who have ridden both aluminium and steel frames would say that aluminium frames are stiffer. Actually, steel has a much higher Youngs modulus than aluminium - it is stiffer. It's just that aluminium tubes tend to be much larger in diameter than steel, and as a tube's diameter increases, its stiffness increases to the third power of that number.
In reality, the tyres, the wheels, the seat posts and the saddle proper absorb the bumps. The frame itself contributes little or nothing to shock absorbency. It's also important to remember that two frames made from different materials would not be made to the same tubing dimensions, making a relative comparison impossible.The frame feature that does have some bearing on comfort is the design of the rear triangle - the triangle formed by the seat post tube, the chain stays and the seat stays.
The most deceptive aspect of modern bike frames is weight. The frame of my newest road bike is carbon (Toray T-700SC carbon, if you must know). It weighs under 1.5kg. It's 'Phwoarrr' - light. People who aren't familiar with modern road-racing bicycles pick it up and actually go, 'Phwoarrr' Unquestionably, the lighter a bike is, the easier it is to pedal uphill. But the industry has become obsessed with making bikes lighter when, for the vast majority of riders, the paramount consideration is not weight, but that a frame should not break in use.
Carbon fibre is currently the most popular frame material for elite professionals, largely because it is so light. If your absolute priority is having the lightest bike possible, because you're a professional cyclist and you need to shave seconds off the time it takes you to climb a 20 km mountain in the Pyrenees, to give you a competitive advantage, make a living and put food on the table for your children, then you must have a carbon frame. For the rest of us, it's either an indulgence or we're victims of a conspiracy. Or both.
Yes, even the bicycle industry has a conspiracy theory. It goes like this: the manufacturers of mass-produced bicycles spend a fortune on R&D to ensure that the top professionals they sponsor ride the lightest, fastest bicycles, and win races. The manufacturers need to recoup this expenditure while reducing the costs of production, so they throw everything at marketing to the public the same, or similar, elite bikes as the pros ride.
My dream bicycle will be made from steel. Here's why:
1. Steel is very strong. High-quality steel has a very high yield strength or elastic range - the point at which it bends permanently rather than bends back to its original shape - making it durable and less likely to bend in a crash. This means that steel tubes can be thin, with a small diameter, making steel frames light and sufficiently flexible. As people like to say: "steel is real".
2. Steel has a long life. When I visited Argos Cycles, a well-established frame-building workshop on an industrial estate in Bristol, I was shown several dozen steel frames dating back to World War II. There were frames made by some of the great names, such as Hetchins and A. S. Gillott, hanging on the wall, awaiting restoration work. They were about to be realigned, shot-blasted, rubbed down, primed and resprayed. Further along the wall there were several fully restored, gleaming frames waiting to be collected. They looked brand new. "Years of riding left in them," Mark, the workshop manager, told me. "We have a near constant supply of steel frames in for restoration. Many are over fifty years old. A carbon frame simply won't last anything like that long."
3. Steel is not prone to sudden failure: despite recent advances, carbon still is.
4. Steel is also easily repairable: aluminium, carbon and titanium are not. In fact, a small crack in the chain stay on a carbon frame often means the whole frame is destined for the bin. Crucially, steel can be repaired anywhere in the world by a man with a blowtorch and a welding rod. I know this, because I bent a steel bike in northern India, when I was riding around the world. I was slipstreaming a tractor on the Grand Trunk Road near Amritsar. We were going downhill at a lick when I rode into a pothole the size of a hot tub. There was no time to react. I had what American mountain bikers call a "yard sale". The bike, panniers, sunglasses, water bottles, tent, pump, map and I were strewn across the tarmac. I lost a lot of skin but the bike took the brunt of it: the top tube and the down tube were both bent, leaving the front wheel shunted backwards, rubbling against the underside of the down tube. I wondered if my round-the-world ride was over.
It took me an afternoon to find the best mechanic, or "top foreman" as the locals called him, in Amritsar. Expertly, he removed the handlebars, the stem, the forks and the stressed headset from the head tube, while peons handed him tools as a nurse attends a surgeon. Then he shoved a metal spike through the head tube and literally bashed the tubes straight again. It was terrifying to watch. Thirty minutes later, he'd reassembled the bike. The job cost me 100 rupees (about £1.50) and a packet of fags. I still had 12,000 km to go to reach home. The two bent tubes had to welded again in Gilgit, Tashkent and then Meshad, in Iran, but I did get home, on the same bike. The bare frame, still bearing the wounds, is on the wall in my shed.
For years after my return, I was reluctant to take the frame back to the frame-builder, Roberts Cycles. The marks left by the Iranian welder were heinous. When I eventually did go back, I explained to Chas Roberts what had happened. He was delighted. He thrust me into the retail part of the shop where two men were about to wheel away their brand-new expedition touring bikes - one to cross America, the other to circumnavigate Australia. "Here," Chas said, "listen to Rob's story. This is why you've bought steel frames."
Rob Penn - author, journalist, presenter and cyclist - has been round the world on a bike. He's chronicled his search for his perfect bike in his 2011 book "It's All About The Bike: The Pursuit Of Happiness On Two Wheels" (Penguin UK). In doing so, he's touched upon many aspects of cycling - design, culture, technology, history, science, craft and the accumulated knowledge passed on to him or learned through many years of riding a bike.
This extract, reproduced with his kind permission, explains why he chose a steel frame and how he and his steel Roberts survived a nasty accident in Northern India.