The Enigmatic Mystery of Gears

The Enigmatic Mystery of Gears

Many moons ago, people rode bicycles of all shapes and sizes. One of the early varieties was called a Penny-Farthing because it had a huge wheel at the front and a little teeny one at the back. This was, in part, because gears and freewheels were unknown and this configuration was at one time considered more efficient (believe that?). Anyway, because the pedals were welded to the front wheel, for one revolution of the pedals, the rider traveled a distance equivalent to the circumference of the big wheel (usually measured in inches). Big wheel equals large circumference; hard to pedal but a longer distance traveled. If the drive wheel were smaller, hence a smaller circumference, the Penny-Farthing would be easier to pedal but a shorter distance traveled for each revolution. Think about it. It’s true. Promise.

Why on earth do you care? When bicycle gears were finally invented, the original concept stuck but the arithmetic got distinctly more complicated. What gears do is to effectively combine in one device, the hard-to-pedal situation (high gears for a tailwind or going down hill) with the easy-to-pedal alternative (low gears for a headwind or going up hill or when you’re just plain pooped). Now for the only equation in this whole article. Another promise. The gear number (in inches) you are using at any particular time is the number of teeth on the front chainring divided by the number of teeth on your rear sprocket times the diameter of the back wheel (to be absolutely 100% correct, this equation should also take into account tire size and crank arm length but the extra accuracy so achieved is fairly minimal). Now you can forget that. Just remember that the high gears (hard to pedal) are big numbers, the low gears (easy to pedal) are little numbers.

On modern bikes, the number of gears you have, in theory, is the number of chainrings on the front (either two or three) times the number of sprockets on the back (usually 8, 9 or 10). For example a double chainring with a 9-speed cassette gives you a maximum of 18 gears. I lied, that’s actually another equation but it’s so easy, I cheated.

When you are zooming along with a tail wind, you need a high gear ……. big chainring and a SMALL rear sprocket. When you are struggling up the next hill you need a low gear ….... small chainring and a LARGE sprocket. If you want to convince yourself of that, look at the gear definition equation above.

However, life is not that easy. If we look at a typical road bicycle with two chainrings of 52 and 39 teeth and rear sprockets from 12 to 25 teeth (nine speed), the gear numbers look like this:

	12	13	14	15	17	19	21	23	25
52	114	106	98	92	81	72	65	60	55
39	86	79	74	69	61	54	49	45	41

This is a reasonably effective “all-round” set-up. The highest gear (the 52/12 combination) is 114 inches, the lowest (39/25) is 41 inches. Two things to note right away. If you wanted to start in your lowest gear and work your way up sequentially to the highest gear, you would need to switch back and forth between your front chainrings. The lowest gears are NOT all on the small chainring. The second thing is that when you are sold this as an 18-speed bike … its not really true as there is some duplication of gears ….. for example, the 39/17 combination is just about the same as the 52/23.

Life gets even more difficult because it is mechanically undesirable to run your chain from the biggest chainring to the biggest rear sprocket or from the smallest chainring to the smallest sprocket. This is because the chain then runs through the rear derailleur, the front chainrings and the rear cassette at a sharp angle, causing wear and reducing their life. Thus, in the example above, the 55 and 86-inch gears should generally not be used. That means that by not using these two combinations and eliminating duplication of gear combinations, your 18-speed bicycle is effectively a fourteen-speed machine or thereabouts. But that’s OK.

So when you buy a bicycle, should you care about what gears it comes with? Absolutely. If you are a self-contained camping tourist hauling oodles of gear up the hill from Vanderpool, you would want a triple chainset with ultra-low gears on the rear, something like this:

	13	15	17	19	21	24	27	30	34
52	106	92	81	72	65	57	51	46	40
42	85	74	65	58	53	46	41	37	33
30	61	53	47	42	38	33	29	26	23

This set-up has half a dozen or so lower gears than the first set-up we looked at and the lowest gear is “twice as low”. Some would argue that even on this configuration, the highest gears are too high. And before you scoff too much at the triple chainset (disparagingly called a ‘granny gear”), remember that Lance Armstrong’s US Postal Team have used them to good effect in European racing. Admittedly the hills were rather steep.

For a competitive or sports cyclist on flat course, he or she would have very closely spaced, relatively high gears:

	11	12	13	14	15	16	17	19	21
53	126	116	107	99	92	87	82	73	66
39	93	85	78	73	68	64	60	54	49

The lowest gear on this set-up is in the middle of the range for the ultra-tourist and the high gear is also 20% higher. Note that if a high-end component group were used, it would have a ten-speed rear cassette that would give even more closely spaced gears.

Whatever you eventually choose, you will need a low-enough first gear for you to comfortably climb hills, a high-enough top gear to meet your need for flat-out speed, even steps between ratios across the entire gear range and a smooth shifting progression that minimizes double shifting (having to change chainring and sprocket at the same time).

So now how do I use all these gears I have? That could easily be another article on its own but I will make a few generalizations.

I think that too much is made of constant cadence (keeping the number of pedaling revolutions per minute at a constant rate) though I definitely subscribe to the argument that there is a most effective cadence for a given situation. Many cycling aficionados insist that constant cadence is the most effective way to pedal but I personally find there are times when I want to spin in low gears and other times when I want to mash the higher gears. Without doubt, however, you will see beginners pedaling at a gazillion revolutions per minute and getting nowhere and others who are pushing gears so high, their legs seem to be almost motionless (and screwing up their knees into the bargain). Neither extreme is efficient but you do have considerable latitude within the “acceptable” cadence range (70 – 110 RPM for most riders with something around 90 being optimum for flat roads).

Even going up hills there is no universal “right” way to tackle the grade. You might choose to power up a short steep incline in a relatively high gear whereas on a long gradual climb you might want to sit back, arms on the tops of the bars and pedal up in a lower gear. There are actually several techniques for climbing, as well as specific approaches dependent on physiological factors (body size, muscle type, etc). In general, bigger cyclists tend to do better climbing seated, while smaller mountain goats tend to do better standing. The average cyclist should try riding the first 2/3 of a hill seated, spinning a smaller gear. Then the last 1/3 could be done in a slightly higher gear, while standing in the saddle.

And finally, remember three things. First, start off in a relatively low gear until you are well and truly warmed up. Second, experiment with different riding styles and techniques. Third, watch more experienced cyclists (who may or may not be stronger) in given situations and talk to them about why they are choosing a particular gear. Ignore the Smart-Alec answers but also keep in mind that all riders are different. What works for them, might not work for you.

And of course, if you want to read more there are oodles of websites out there. A couple to start with would be http://www.kenkifer.com/bikepages/touring/gears.htm and http://www.sheldonbrown.com/gearing/index.html

Real Men

Real Men

Smooth as a baby’s buns - but is that the way they’re meant to be?

The blood dripped from my body and a soggy mess accumulated in the bathtub which was rapidly acquiring the appearance of a butcher’s shop. It was a greater emotional wrench than losing my appendix, tonsils or adenoids – all of which had been removed by surgery years ago. After all, it had been part of my body since puberty and now was to be consigned to the dark sewers of the city. All in the name of “coolness”, fashion and peer pressure, despite weak attempts at more rational explanations by way of massage, aerodynamics and the healing of wounds.

But I had done it. Even after having secretly mocked those of my friends who preceded me. Now, once the blood has dried and the gashes in my flesh have begun to heal. I revel in the soft smooth skin and intimidating definition of the huge muscles. No longer are these delights the closed domains of women. Real men shave their legs.

Crumpton Cycles: Continuing an American Tradition

Crumpton Cycles: Continuing an American Tradition

Let’s face it. Given that frame materials and production processes have become so advanced, a stock bike will be more than adequate for most of us and thus the vast majority of riders who buy a custom machine are rarely buying their first bicycle. But once we move into that rarified atmosphere of bicycles that cost upwards of $4000, then the custom alternative becomes increasingly attractive. Just interacting with the elite group of individual artisans who craft them, understanding their design & build philosophy and realizing that the end-product will be both unique and will achieve that 95% solution that we crave ….. now we are talking about something truly special. However, only by talking directly with a custom builder will you be able to share his or her infectious enthusiasm and benefit from their expertise. Perhaps that’s easier said then done. First, custom frames have historically been in built in steel, sometimes in aluminum or titanium but rarely in the increasingly desirable carbon. Second, alas, most builders are at least a day’s flight away. But don’t fret; there is a local alternative. Here in South Texas there is a nationally-recognized carbon builder, Nick Crumpton of Austin. But before we discuss Crumpton Cycles, let us take a look at the last few decades that brought the custom frame business in America to where it is today.

High-end frame builders in the US were a relatively rare commodity in the post World War Two days, with the notable exception of the Schwinn Company (who had introduced the legendary Paramount in 1938). For the most part, Europe ruled those roads with classic Italian steel machines such as Bianchi (1885), Pinarello (1952), De Rosa (1953) and Colnago (1954) and their many well-established English rivals which included Harry Quinn (1909), Bates (1926), Holdsworth (circa 1930), Ellis Briggs (1936), and Mercian (1946). In 1949, the British contingent was joined by Ernie Witcomb in Deptford, London. His son, Barry was to play a future role in the establishment of a cadre of high-end American builders.

Fast-forward to the 1970s when aspiring American frame builders turned to their English cousins for inspiration. Both Ben Serotta and Richard Sachs traveled to Deptford to study frame building at the now prominent Witcomb Lightweight Cycles under the tutelage of Barry. Witcomb (USA) was subsequently established in the early 1970s with both the celebrated Sachs and Peter Weigle as frame builders, though the American subsidiary barely survived the decade.

Nevertheless, the foundations of a US-based artisan industry had now been established, with Serotta, Sachs and Weigle eventually setting out on their own as independent custom steel builders. They were joined by other master craftsmen who included Bruce Gordon, Tom Kellogg and Dave Moulton (who had also learned the craft in his native England and later with U.S. Masi). These and other notable US builders were soon turning out superb steel frames.

In the mid-1970s, three seminal events took place that were to further transform the bicycle frame business on this side of the Atlantic. The first was in 1974 when Teledyne marketed the first titanium bike that was produced in any quantity. Both the innovative guys at Merlin and the Lynskey family at Litespeed were eventually able to bring titanium frames to a broader market in the mid-1980s. The second was when Gary Klein displayed his revolutionary welded aluminum frames at the 1975 International Bike Show. This led the way for Cannondale to launch their highly successful line of aluminum bicycles in 1983. The third milestone was the 1975 appearance of the first carbon-tubed frame, the innovative Exxon Graftek. It was built with stainless steel lugs and suffered frequent frame failure but did set the stage for the successful application of carbon technology in the mid-1980s by Trek and others.

The gradual acceptance of these “exotic”, non-ferrous frame materials opened up a huge number of possibilities with different builders and companies experimenting with every possible permutation of aluminum, titanium and carbon fiber for the frame’s main tubes stays and forks. As a result, the custom frame business diverged, with individual builders such as Richard Sachs and Bruce Gordon remaining committed to classic steel whereas Ben Serotta and Tom Kellogg led the way with non-ferrous combinations.

The carbon revolution really exploded in the first few years of the 21^st century with mid-level frames and components being produced in the Far East for relatively little cost. However, ever since Kestrel had introduced their non-lugged, carbon fiber frame in 1986, the large-production trend gradually moved towards the monocoque (one-piece) molded products. Since the cost of custom molds for individual customers would be prohibitive, the artisan carbon builders stayed with a more “traditional” lugged construction, except that their methodology was far from traditional. Craig Calfee in California was one of the early custom carbon builders, establishing his first production machines in 1989, under the name Carbonframes (changed to Calfee Design in 1997). Bob Parlee in Massachusetts joined the small and elite cadre of carbon builders in 2000, employing his knowledge of composite fabrication from having previously built custom boats.

And what about Nick Crumpton? His passion for bicycles started as a racing cyclist but his birth as a builder began when he learned frame welding techniques at Bike Friday in the mid-nineties. He subsequently started building his own steel frames after he moved back to Austin. Around 2003, the idea of building custom carbon-composite bicycle frames took hold and two years later he left his full-time job and founded Crumpton Cycles. Still in the workshop in his backyard, he remains that company’s only employee. It’s he who answers the phone and he is “the only man that will touch your bike from start to finish”.

He firmly believes that carbon frames provided greater strength for their weight and has developed a process for using tube- sets that allows him to ensure both exceptional durability and ride quality. A critical goal is to achieve optimum balance and weight distribution of the rider on the finished product. After extensive discussions with the customer, examining their current bicycles and taking whatever measurements are required, the new frame geometry is determined and the specific tubes are selected for that individual.

Crumpton’s specialized equipment allows him to make extremely accurate tube cuts, thus offering individualized frame angles down to fractions of a degree. The initial epoxy-joining of the tubes is followed by carbon wrapping the head tube, seat-tube and bottom bracket joints. Even though he has tested his initial joints before the carbon wrapping and determined that the tubes will fail before the joint does, the wrapping process is still essential because this allows him to further tune the ride quality. For example, for a heavier rider wanting a stiff frame, Crumpton will use both more layers of carbon around the joint and will extend the carbon layers further up the tubes. The frame is then subject to the heat and pressure that produces the final bond between the wrapped “lugs” and the tubes.

In this weight-obsessed world we cyclists have created, it has to be said that his Superlight frame begin at 850 grams; that’s well under two pounds in case you were wondering. He is now working on prototype Ultralight frames that will weigh around 650 grams. Crumpton attracted considerable interest early this year when he worked with Group de Tete in North Carolina to produce a fixed gear bike which came in around seven pounds and yes, that’s for the whole machine.

Crumpton Cycles has a capacity of around 60 frames per year for as long as Nick remains the only builder. All his road and cyclo-cross frames come with a 10-year warranty and are offered either clear-coated or with a custom paint job. He is also moving into the component arena. Bicycling Magazine’s recent super-bike featured a Crumpton bar-stem in which he takes a carbon bar and carbon-wraps it to a machined-alloy extension to form a stiff one-piece combo. At this time, his component line is only available to purchasers of complete frames.

In addition to the small but growing number of satisfied customers, Crumpton has received prestigious accolades from his peers. At the Handmade Bicycle Show in Houston in 2005, he was recognized with two awards including the Best Carbon frame. Remarkably, this achievement was repeated at the 2006 Show in California. Nick Crompton’s advice to any rider seeking the ultimate custom machine is simple: “Buy your frame from somebody who actually rides bicycles. Only then can the builder truly know what he is talking about”.

Even though this is not an article about bicycle fit, it’s worth reinforcing this point with another axiom from Andy Pruitt, the Director of the Boulder Center for Sports Medicine and one of the world’s foremost expert of bicycle fit. He emphasizes the critical need for “dynamic” fit to complement the more traditional “static” fit. Body measurements from a motionless rider can only represent one piece of the puzzle and observations on the rider when he or she is pedaling are essential for a complete analysis. Only one-on-one interaction with the frame builder will effectively achieve this goal. For more information on Crumpton Cycles, e-mail nick@crumptoncycles.com or visit the web site at www.crumptoncycles.com.

MOUNTAINS, HILLS OR JUST BUMPS?

MOUNTAINS, HILLS OR JUST BUMPS?

Here in Texas, we will rightly pat ourselves on the back when ascending our local hills such as Tower View near Helotes or the hill leading west from Vanderpool or, further afield, the climb up to the observatory in Fort Davis. But how do these hills compare with the rest of the world? Although the discussion below focuses only on the steepness or grade, this is clearly only one piece of the puzzle. The effort needed to complete a hilly ride depends on a host of other things including the total elevation climbed and the altitude you are at (there is less air to breath as you gain altitude and that means that you are getting less oxygen into your blood).

When you travel through the mountains, you might see signs that read "Trucks check brakes: 10% grade". These numbers obviously have something to do with the steepness of the road, but their exact meaning is a mystery to many cyclists. So, what is the grade? The formula is quite simple: vertical feet gained ÷ horizontal feet traveled (1 mile = 5280 feet). For example, Monarch Pass in Colorado ascends approximately 3000 vertical feet in about 10 horizontal miles, so 3000 ÷ (10 x 5280) = 0.0568 or 5.7% average grade. In this example, the figure is an average; obviously over a ten-mile distance, the road will include steeper and flatter sections. To be accurate, remember that the horizontal distance is exactly that and so using your bike computer distance in lieu will give an inaccurate value. You are obviously not traveling horizontally when climbing a hill! High-school trigonometry (remember Pythagoras?) will, however, enable you to calculate the correct number. ¬ It’s also worth noting that in some parts of the world, the grade is expressed as a ratio rather than a percentage but the trigonometry is essentially the same.

Even if you're a better-than-average cyclist, there are many areas where your legs might cry out for very low gears. Let’s take a look at some examples. The steepest sustained grade on Ride The Rockies is typically 6 to 7%. You might expect to climb grades of this class for ten uninterrupted miles but occasionally, a route will include a short stretch of road as steep as 10%. The Blue Ridge Parkway is another example. Mile for mile, it has some of the steepest grades (7 to 10%) of any roads in the country. Even steeper, however, is Wolf Creek Road in Oregon where the steepest stretches reach 17%.

What about Europe? A rider going from Land's End to John O'Groats by bicycle (the whole length of Britain) writes: “Lindsay and I encountered the longest and steepest hills I have ever met on a bicycle, more than one indicated by a 30% road sign. On several of these ascents I simply could not make it.” Also in England, the Rosedale Chimney, on the North Yorkshire Moors, climbs up to Blakely Ridge where you can find “The Lion Inn”, the third highest pub in England. It is famous amongst cyclists being a 33% climb that has been used in some racing events where some racers are invariably reduced to walking.

An Italian cyclist records: “The hardest climb I know is in the Euganean Hills, southwest of Padua. It's known as the Pirio and it is infamous. A sign at the bottom says 22%. It requires absolute concentration and an iron will. If you falter, either mentally or physically, it's all over.”

In Germany, a rider takes some risks on a descent: “Here Northern Bavaria, the steepest climbs are some roads of 23% to 27%. Some old roads go simply straight uphill; the 27% road is actually banned for bikes going downhill. My usual apology is that I was unable to decipher the road sign while going downhill at that speed.”

And what of the world’s most arduous sporting event, the Tour de France? The Alpe d'Huez stage is one of the toughest. The first kilometer is like a wall, rearing up at 11%, the steepest pitch of the 13 km ascent. The stage also includes the Col du Glandon, a 21 km uphill averaging 6.9% but where the final kilometer reaches 10.4% before reaching the peak. As we are in Europe, let’s not forget the Tour of Spain's killer stage, Angliru. This is the Vuelta's most feared and notorious climb with 13.5 kms of climbing including 14% - 23% stretches. This year the U.S. Postal team took precautions: "We spent all night turning the machines into mountain bikes. The Posties were riding 12 x 25 on the back and 30 x 39 x 53 on the front.”

Think that sounds wimpy? Consider taking on Baldwin Street in Dunedin, New Zealand, the steepest paved road in the world at a 35% grade. This stretch of pavement rises one foot for every 2.9 horizontal feet. “I stopped, stood over my bike and took a look up there. The street started out flat, and then gradually began to slope upward, more and more until about the middle, where it was very steep. But from there it just kept getting gradually steeper and steeper until, close to the top, it was hugely and ridiculously steep. I could see that it wouldn't be easy to get up there on a bicycle. Of course I'm rarely the kind of guy to do things the easy way.”

Now let’s get back to Texas. Of the rides that we do from time to time, the toughest ones are probably Utopia-Leakey where there is a total of 3300 feet of climbing (on the 49 mile ride) and Bandera-Utopia where there is a total of 4240 feet of climbing (on the 69 mile ride). However, the absolute grades on these rides are not as steep as some of the short hills we tackle that might reach 18-19%. Such grade values certainly are not averages but rather represent a short, steepest segment of the hills. They do not reflect the overall difficulty or the endurance that might be required to accomplish a ride; however, a high numerical figure represents a hill that would require some very good climbing gears to ascend without dismounting.

Further west, one of the steepest continuous roads is on River Road between Presidio and Lajitas. One side is 17%, the other direction is 15%. And finally, Fort Davis. On the 75 mile loop, there is a remarkable 5075 feet of climbing, almost a mile! And steep; one tourist deliberates: “The road flattens, and I come to the turn for the McDonald Observatory Visitor Center, just to the north. Here I stop to catch my breath, top off my water bottles, and consider if I will attempt the 1.2 mile, 17% grade climb to the McDonald Observatory at the top of Mount Locke. The cycling guidebooks agree that everyone should try this side trip up the steepest slope to the highest point on a paved road in Texas (6,791 feet), but this time I decide not to take their advice. I have many miles of unfamiliar mountain roads still to come and prefer to save my legs for the unknown.”

I did too.

¬ for more details on this calculation, see http://www.howstuffworks.com/question380.htm