Battling The Tour de Off-Season

Cattaraugus, NY

For many here in the northeast of the U.S, crusty golden leaves have begun to fall, signaling the time of the year when we must take give our a nuts a break off the bicycle saddle and gather other edible nuts for winter.

We are to find out our losses in upper body strength and try to "cross-sport", which must be like "cross-dress" to those 50-50 human beings, you know...to find out what the other exciting side of the grass is like.

After emptying the family budget throughout the year buying bicycles, racing bicycles and driving huge vehicles to buy them and then hauling them around like a Bedouin to race them all over the place, we are going to try new things, lust after new gear, and bring the family budget to negative on the number line.

We're going to spend night in and night out of Ebay worse than a prostitute in a red light district of Bangkok, bidding on this crankset and those wheelsets and that headset because our well, our headset up there on the shoulder is a little out of torque, we're not satisfied with what we have and think we could be faster with the fancy colored ceramic bearings originally designed for machines that churn out raw materials for society in excess of 20,000 rpm. Nope, we must have it.

Not to mention, such night sessions of Ebaying will take a toll on us as we gain weight each day by the pound.

Sometime later, we'll start the "training" again and buy loads of cycling books to read because turns out, none of us know zilch about mambo-jumbo like periodization and TSS and FTP and BSS and all that BS.

When the training kicks in, it comes in myriad forms like wind trainers and rollers and fancy virtual reality and scandalous indoor spinning classes. For those of us who can't afford any of the above, we'll just pretend to spin a high gear in the bathroom while showering and then do calf raises after that, and somehow get the impression those legs will get big in the hot water over a couple of months. You know, the air-cycling version of air-guitaring.

Oh and must I say, half the training mentioned above will be consumed in trying to get rid of the weight we put on in winter. The other half lands us precisely to the fitness level we started out last year. And then we walk proud and upright with an S-curve in the back thinking we are stronger cyclists. Note : This is not applicable to those of who air-cycled in the bathroom as most of them will slip and fall on their bottoms in soapy water anyway.

The final stage of this Tour de off-season comes when renewing races licenses and buying extra licenses and so on, just in case one got lost, voila, not to fear here's another one in my organizer. Cat 1, cat 2, cat 3...what's that mate...is that a part of the cat family? Do they snarl?

When all is said and done, its a great off-season and its the journey that matters, yeah?

By the way, why the heck do they even call it off-season? There's nothing off about this silly affair.

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Happy Halloween and yes, have a great....off season !!!

A Word On Bicycles And Radios

Think back to a great speech, an interesting musical composition or an experience of going through a historical event live and chances are, you probably heard a good portion of them on the radio.

Riding a bicycle and going places also instills deep memories. In developing nations, kids ride bikes to school. Men make money through bicycles. Entire families are seen transporting themselves from village to town and vice versa. For most of us, we remember routes and places better when we take a trip there by bike.

One could argue that both the radio and the bicycle completely changed human society, and the way we live today. They are metaphors for social progress. The bicycle has offered a cheap means of transport for millions of people across the world for over a century. It increased personal freedom, elevated personal health and has had pivotal roles to play in the emancipation of women.

And without the radio and closely related wireless technologies, perhaps the Allies wouldn't have even ended either of the World Wars. I mean, there's nothing more gripping and nervous than the threat of war, I'm sure we can all agree to that. So imagine conducting battles, moving tens of millions of people and resources across nations, directing complex artillery to places you cannot even see and making concerted decisions relevant to governance, information and security via horses, mail coaches and pigeons.

The radio has been a cheap information source. We don't have to know what's in it. There's a fantastic level of abstraction to this technology. The package is great! And through the ether or whatever that stuff is up there, it brings us music, tidings, propaganda and sports broadcasts. All we have to do is sit somewhere and turn the knob to the right places. Then shut up and listen. Its simple and beautiful.

The bicycle takes a day or two to learn. Okay, at most 10 days, maybe a fortnight. But the thrill of finally getting to ride one must far overwhelm the initial effort. Once on a bicycle, the rider is in tune to everything around them - the breeze to the face, the direction of the wind, the inclinations of pathways, the people and the surroundings, the quality of the air, the temperature gradients, the sounds on the bicycle. Its a self discovery. Its a discovery of the environment. Its a discovery of mechanisms and how they work.

Should bicycling be like using the radio? Yes, of course. It should be easy to use. So easy, a caveman could do it, that sort of thing. It should be like the radio as an instrument that helps tune personal development, giving the owner great education, memories and pleasure. Riding a bicycle should have an imaginative component, like listening to a radio. It should be a tool promoting shared experiences. Hundreds of people can listen to one great radio broadcast and enjoy it. Hundreds of bicyclists can ride the same beautiful countryside on the same bicycles and enjoy its lush offerings. Why, that concept has been enjoyed by many people for many years.

Should the bicycle be as complex as the radio? The radio is complex and its there for a reason. But the complexity is hidden through abstraction. All we see is the outer case and a couple of knobs. But if something goes wrong with it, we have to sit and RTFM - Read The Fine Manual. If its necessary, you must take it to a specialized individual to have it fixed.

Is it necessary to pollute the bicycle with unneeded complexity? I guess it depends how you think about that. Here's what I feel. Not considering bicycles used purely for specialized hobbies, the common bikes that people ride for transport and living must be kept simple to a large degree. Most normal people equate happiness with simplicity. It must feel great to have a tool that's easy to use and is easy to figure out what's wrong if something does go wrong. And how nice it would be to have one that you can use and carry around with you in many places, akin to the mobility offered by the simple radio.

Enjoy this video from Rwanda,. As we can see, there must be something deeply existential in fitting a radio to a bicycle. Can you relate to this special joy?

* * *

Velo Taboo : Underwear Inside Shorts

Attention Cycling Noob,

Just where do you think you're going?? Are you wearing underwear, knickers, lingerie and ofter hardware under your cycling shorts?? If yes, just imagine someone plugged out a huge 8ft stop sign from the ground with utmost urgency and stuck it in your face while an elephant provides the mother of all trumpeting!


Wearing underwear under padded cycling shorts is like riding with your shorts full of broken glass. I mean, imagine someone exploded a Schott glass with dynamite and then slipped the remains from a laboratory funnel right into your shorts. Happy trails!

And we did not even get to the most important part YET.

If you've got cheesy flowers, Mickey Mouse and other nonsense on the underclothing, they'll show through your colored Lycra shorts which will obviously knock the person drafting behind you out of consciousness. Which will then knock the others behind them out of line and others behind them out of their lines... and so on and so forth, until you're all done with a wonderful zero mile ride and all you've done all day is collecting loose pieces of skin from the road to piece yourself together.

Oh..alright...maybe if you're the type of bloke who likes to shoot for a Nobel Peace Prize in microbiology, we might be able to understand why the multitude of fungal infections harvested from the bulbous boils around your nether regions are of any immediate use to you.

So unless you're the above, or you're pulling off a gimmick as an underwear salesman or just someone really bent on publicly exhibiting the variety in the underwear drawer, please oblige and do us all a favor.

While you're changing in the restroom, we'll be having a long talk with your mom.



ADDITIONAL READING :

ShamWow Shammies

* * *

Saturday Stupidity VII

FOR OTHER INSTALLMENTS OF STUPIDITY, SEE :

Saturday Stupidity I
Saturday Stupidity II
Saturday Stupidity III
Saturday Stupidity IV
Saturday Stupidity V
Saturday Stupidity VI
Saturday Stupidity VII
Saturday Stupidity IX

* * *

E-Hub Marketing : A Important Lesson In Statistics

Like the past 100 years, even today cycling products come and go. And with them, so do their marketing sound bytes...

Any intelligent cyclist must carefully inspect marketing data handed to him, and question what is missing and why its missing. Weak data can lead to weak correlations, spurious percentage differences and other logical fallacies. Until the missing numbers are accounted for, I don't advise anyone to take faith in where they put their money.

When James posted a small article yesterday on the E-Hub at the Bicycle Design blog, I got very amused and decided to take a peek at the product website. I spent a little time looking at the interesting item proudly displayed but then had an itching desire to see the numbers behind the invention. Not just plain numbers. I wanted to see if they're meaningful numbers.

This page has a statement from Dr. Alen Orbanić (a University mathematician from Slovenia) telling us that the designers behind the innovation carried out a surefire experiment to prove without doubt that using the E-hub for cycling showed the following things :

1) Increased average power output when compared to cycling with a conventional rear hub.

2) 4% reduction in average and maximal heart rates in cyclists using this product, when compared to the same figure for cycling with conventional hub.

3) 10-15% of blood lactate reduction using the E-hub versus using a conventional hub.


So What Was The Experiment?

Well, I'll tell you the part of it they conducted outdoors. They brought together a population of cyclists from 20-60 years of age. How many? Not specified. Then they categorized them as "Professionals", "Recreational" and "Amateurs". How did they define who belonged where? No indication. What were their weights, fitness levels etc? No indication.

So this population of cyclists were asked to fit themselves with a Polar heart rate measuring system who then mounted Ergomo powermeter fitted MTBs to ride a 2km track (1.24 miles) with 14 degrees of average inclination. Apparently, they did this twice, one with the E-hub and one with a classic hub after 24 hours of rest between the two. Levels of lactic acid were measured twice, immediately after each run with a hub.

Fig 1 : A snippet showing how things were measured by the authors. Typos abound. Click to zoom.

I'm surprised a tad bit by two things. 14 degrees of average inclination? Wow. That is an average of 25% grade. Second, I'm surprised recreational cyclists could manage this effort. Either Slovenian humans are exceptional, or the drive train was really dumbed down for spinning, or something is just plain wrong with this number presented to us. I have written in the past about the W/lb required to maintain a certain speed on a given grade.


So What Does The Data Look Like?

The authors go on to claim they gathered a "vast quantity of data" but for the sake of the reader's reading convenience, they picked 3 'random' data points corresponding to 3 cyclists, for each class of cyclist. I guess this is a solid example of where you can't really thank people for their kindness :).

Here are the numbers :

Fig 2 : 3 randomly selected cyclists in each class showed the above numbers with and without an e-hub. And how were they randomly chosen? No indication so could we not say this is an example of data mining?

Fig 3 : % differences in heart rate and power between the two hubs.

Fig 4 : % differences in average blood lactate between the two hubs.

Right off the bat, I see this is poorly presented data, at least for a professional level. From the surface, I can come up with 3 weaknesses :

1. Sample Points & Averages : There's a rule of thumb in good statistics. You need a minimum of 30 sample points before you do descriptive analysis on it to explain trends.

Take a look at the amount of power these cyclists are producing on this so-called 25% grade, 1.2 mile track. Professionals are producing puny average power outputs while recreational and amateurs are easily rivaling them, not only in power but also in speed.

This leads me to question firstly how the authors classified and defined these cyclists. It seems to me from this meager amount of data that all three classes were almost equal in their cycling abilities?

I also have to say that averages can fool you if data jumps all around the place wildly. For the meager sample points presented above, you can see that the average power is pretty sensitive to outliers.

Infact, if we had been handed 30 sample points or more for each class of cyclist, it is likely the data could have shown a decreased average power, which could have reduced the resultant power differences between the E-Hub and the classic hub. Any guarantee that's not the case? The authors haven't proven it here but go on to artificially bump up the averages using just 3 data points mined from here and there. Furthermore, their conclusions about the apparent efficiency increase with the E-Hub is only relevant for these 3 sample points.

2. Spread : Closely following the absence of more samples is the question, what's the spread and deviation of this "vast amount" of data? I don't have any idea of it as there's no indication of standard deviation. The data is meaningless. How can I tell if a majority of data points in this experiment are close to the average power output or not? What if outliers are pushing the average up?

3. Range : Because only one sample data point (for power, HR and lactic acid) have been presented to us going across for each cyclist, we have no idea of the true range, or the true maximum and minimum values that would be observed. The data point presented to us is just one of what could be many and they are all bound to vary, because that's how all processes are... they vary! Hence, the range could vary pretty significantly if we had more tests on the same individual.

4. Instrument & Measurement Error : Lastly, what about the instruments used? Were they calibrated properly and accurate to other power measurement systems? What's the bias in the system, if any? Are these numbers from just random variability or regression to the mean? It is often taken for granted by some that measurement systems (instrument+human operator) that produce such outstanding numbers are always pin-point accurate.

I simply have to conclude that this data, so far, to me is just meaningless. The rest of the data that follows on the webpage, done on an indoor ergometer, suffers from exactly the same types of weaknesses I have mentioned. These are basic rules to follow in statistics and I'm surprised they weren't in this case.

The product itself may be great. I cannot disagree for certain there. But the numbers don't show me much so far. Thus, I think the declaration that this hub system really improves the efficiency of a cyclist compared to what we usually use must be taken with a handful of salt.

* * *

Edge Composite 68 Carbon Wheel Failure

Our protagonist, the author of a blog called "Manley Man", had recently participated in Levi Leipheimer's GrandFondo ride in California. Among the highlights of this ride are really steep descents, some of which feature blind corners.

One of these, called Meyer's Grade Road, was an 18% grade technical downhill and the Manley Man was being pretty cautious going down this road, hitting his brakes every now and then (okay, 'every now and then' maybe a huge assumption from my side). Yet, towards the bottom of the descent, he found things out the hard way. Observations were described thus :

"Toward the bottom third of this descent I felt a very bad pulsation in the front brake lever. I looked down at the front wheel to see if there was something wrong but there wasn't anything visibly bad. But it was scary to see the fork flexing back and forth under braking; it probably was oscillating at least an inch when I had the front brake applied heavily.

I got to the bottom of the descent and my teammate pulled over a few seconds later to see how I was doing. I spun the front wheel and it got stuck. It wasn't clear to me what happened. I opened the brakes up to let the wheel spin more freely. At this point I saw the issue. Initially it looked like the sidewall of my Rubino Pro had bulged out and was rubbing the break pads (yellow Swiss Stop). But to my surprise it actually was a deformity of the braking area of the rim! I had somehow managed to melt the carbon!"

Here's the deformed wheel, picture courtesy of Manley. The original specs of this clincher can be found on the product page. Because its a clincher wheel, the carbon braking track has to withstand the pressure inside the tire.

Manley Man limped through the rest of Levi's ride, being able to use what he estimated as only 10% of his total front braking power. He says that he'll be on the phone with Edge Composites having a long talk with them.

This kind of scenario has been a common topic of discussion on this blog and forums. If you'd like to get a little deeper into rim heating during braking, please see this past article. You may also notice that these kind of incidents happen not only with amateurs, but also professionals on the international stage. See this article.

Now we're all really really wondering what Edge Composites told the owner of the wheel. Will they have it replaced under warranty or pass on the blame to him with no gifts? Manley?

Do you want to discuss the specific nature of this failure? Please include your comments below.




ADDITIONAL READING :

Clincher Failure On Meyers Grade
Rim Heating During Hard Braking
Tubulars Exploding And Peeling Off
Bizarre H Plus Son Rim Failure In Japan

* * *

Analysis Of The Bicycle Endo

The endo, short for end-over or end-over-end, is a type of pitch over crash where the cyclist goes over the handlebars, the weight offset of which causes an inertial moment to act about the front wheel resulting in rear portion of the bicycle to flip in the air above and behind him.

Usually, the cyclist, as a sudden reflex action, yanks out their hands or legs at some point to cushion the impending fall and ends up letting go of handlebar control. Meanwhile, the bicycle is bound to fall either sideways, due to its motion about the steering axis or right on top of the cyclist. In the latter scenario, the saddle or even the rear wheel itself could land on the cyclist's body.

Again, an endo is a crash that could cause injury. It is not a bicycle trick. That one has another name. Its called a 'stoppie' or a 'wheelie'. An endo is caused due to strong front wheel braking or when the bicycle hits a curb, a structure more rigid than the wheel itself. Endos may also occur if the front wheel is loose, i.e, if it is not secured properly to the fork dropouts by the quick release skewers.

In this post, we will cover the "endo parameter", study the relationship between braking force and endo parameter on level ground, outline some common reasons for endos, check out a video analysis of an endo and finally study the relationship between gradient of the road and endo parameter through a literature source.


ENDO PARAMETER

Braking a bicycle naturally upsets equilibrium and transfers weight to the front wheel. With a stark increase in the overall braking force, the load on the rear wheel approaches zero, after which the rear wheel will start to lift off the ground. Hard braking may stop the bicycle but Newton's first law reigns supreme as the cyclist's body continues in motion in the headed direction. This rider motion has some momentum. If not self-controlled, the rider will flip over the handlebars and the bicycle will pitch-over as well. What results is the endo.

It turns out that while outrageous situations cannot be helped, some factor of safety from bicycle design and rider positioning skill can provide for a cushion against pitch-over tendency in the above mentioned situations.

I'll call my main parameter of interest the pitch-over parameter (or endo parameter for lack of a better word) - A/H - as can be seen in the diagram below :

Fig 1 : Free Body diagram of a bicycle-rider system just at pitch-over. Now you may be able to appreciate from geometry and c.o.g as to why recumbents and tandems are stable in pitch-over. O is the point signifying the contact point of the front wheel with the ground.

TERMS :

W = combined rider-bicycle weight
Wf = normal load on front wheel
Wr = normal load on rear wheel
Ff = braking force at front wheel
Fr = braking force at rear wheel
Fb = braking reaction (mass times deceleration)
L = wheelbase
A = location of center of gravity (c.o.g) aft of front wheel
B = location of c.o.g forward of rear wheel
H = height of c.o.g

The endo parameter, A/H (a ratio), in the combined bicycle-rider system should be large enough to avoid front pitch-over. Obviously the vertical height, H, of the center of gravity (c.o.g) and the location of the c.o.g aft of the front wheel, A, are going to vary with variation in rider's weight, height and sitting position.

This highlights why its important to get a proper bike fit for the type of bicycle you wish to ride. Its not just a question about comfort. Its also a question about safety. Enlarged riders who overwhelm miniature bikes not made for their size will quickly find out what they're doing wrong. All they have to do is hit the front brakes hard and they're right on target to be turned into human projectiles.

Looking at the free body diagram above, we can deduce that the system is in static equilibrium about the front wheel contact point O if the sum of the moments due to all forces about that point is zero. In other words, rotation is just initiated at :

Fig 2 : Endo parameter relationship to braking force. This also gives us an expression for the braking force at the point of the pitch-over.

From this simple relation for level ground, we see that endo parameter is equal to the braking force as a percentage of total weight at just about the initiation of the endo. Braking force is a function of the co-efficient of friction at the tire-road interface.

Before the initiation of pitch-over, the braking force-weight ratio is lesser than the endo parameter. Well after the pitch-over has been initiated, the endo parameter falls lesser than the braking force-weight ratio.

We can now infer that making A/H larger is better for safety. Otherwise, a lesser braking force relative to total weight will be sufficient to initiate pitch-over. How? Simply because the braking force-weight ratio catches up with the endo parameter sooner. Oops.

A/H can be fixed to be greater with good bicycle design and proper fit. It can also be superficially made larger by the cyclist while riding by positioning his body rearward (relative to bottom bracket) as the following picture shows :

Fig 3 : A cyclist ducks and shifts his c.o.g rearward to increase his endo parameter

People succumb to pitch-overs because of other factors too. They may not be skilled enough to increase the endo factor, A/H. They also may not be skilled enough to modulate and may tend to hitting the front brakes really hard without realizing that a front brake can cause more deceleration than a rear brake. For comparison, front brakes generate upto 0.5g's of retarding force whereas rear brakes produce a max of 0.1 or 0.2g's. Note that maximum deceleration is limited by the co-efficient of friction between tire and road and the normal load.

You can notice front braking power for some mountain bikes through a speed vs time graph.

Fig 4 : Speed vs Time graphs of MTB's (Courtesy : Beck Forensics)

Obviously, the graphs show that you can bring a bike to a stop faster using the front brakes alone than the rear brakes. Using both brakes is even better for reducing stopping distance even further.


SEQUENCE OF MOTIONS IN AN ENDO

Beck Forensics did an interesting little video analysis of an endo. The following image as well as the snippet below it is taken from a web sampler of their book Bicycle Collision Investigation. It shows the steps involved in an endo before the crash.

A mountain bicyclist traveling at about 22.5 mph (36.2 kph) applies only the front brake. Once the front wheel is nearly locked, the rear wheel starts to lift up. At about 0.20 seconds, the rider really has no chance to recover. At about 0.33 seconds, he releases the brake and prepares his right hand, and then his left hand for landing. The cones are shaped in 25 foot (7.6 m) intervals and the grade is about -2% (descent). (Courtesy : Beck Forensics)

RELATIONSHIP WITH PERCENTAGE GRADIENT OF GROUND

This section is a little more involved. It uses the same analysis techniques shown above to derive a relationship between the "endo parameter" and braking force-weight ratio with the percentage gradient of the ground. You will see that the chances of an endo are more likely on a descent.

The following literature is from one digest of IHPVA (2001), written by a retired engineer named Frederick Matteson. Click on the series of images to zoom the text. Alternatively, you can also read the paper here.

Enjoy!

Page 1 : Click to zoom

Page 2 : Click to zoom

Page 3 : Click to zoom

ADDITIONAL READING :

Budbrake : Proportional Brake Control For Safer Bike Stops
Dynamic Stability Of Bicycle Design : Part 1
Dynamic Stability Of Bicycle Design : Part 2
Dynamic Stability Of Bicycle Design : Part 3
Dynamic Stability Of Bicycle Design : Part 4

* * *

Pedal Force Simulator : Capturing The Outdoor Experience

Components of Pedal Force Simulator

Tom Compton, the personality behind AnalyticCycling.com, believes trainers do a shabby job of simulating outdoor riding conditions. There's that something missing in them.

Well, nothing new there, as most of us have felt the same since time immemorial. We all sit on these mechanisms and fool our brains into thinking we're doing the actual thing.

But what I like is that Compton expresses this "something missing" of trainers relevantly as follows. This collection of statements puts together an obvious problem in need of an engineered solution :

"Acceleration is the root cause of the difference (between actually riding outdoors on bicycles and indoors on trainers). Trainers model average power at constant speed and don't respond realistically to accelerations. So when you get up to sprint on a trainer, the pedal 'falls out from under you'. The acceleration of a trainer is wrong, wrong by as much as several orders of magnitude. After all, the mass of even a large-flywheel trainer is small compared to the mass of a rider."

Compton is now taking trainers one step forward with a cool add-on simulator that mimics real world riding conditions indoors.

How do you simulate real world conditions? It turns out that its all in the resistance force encountered at the pedals. Compton has designed a one package solution, called Pedal Force Simulator (PFS), through which riders can select a pre-programmed force simulator in a Palm device mounted on the handlebars. The simulation model is then communicated wireless to a computer at the rear wheel which then controls the pedaling resistance at about 1000 times per second.

The resistance computer of the PFS at the rear wheel

The PFS uses the standard validated model of forces acting on a rider to simulate instantaneous forces at the pedal. It measures acceleration and, using the standard model of forces acting on the rider and applies a resistive force at the pedals that is theoretically equal to the force a rider would feel riding outdoors under the simulated conditions (or theoretically sound). It does this using an eddy current brake that is electronically controlled by a computer in the resistance unit. The computer recalculates force at the pedals 1000 times per second so that the instantaneous force a rider feels at the pedal is always a theoretically correct force. [Source : Tom Compton]

Fig 2 : The display on the handlebars is a high-end Palm device with a large, color display area. Display software takes full advantage of the Palm device's capabilities. Displays and plots of parameters are provided. Workout data is saved to a sophisticated database. All measurement parameters normally expected are also provided. [Source]

The power of this system comes in customization and as said before, in mimicking outdoor variables. While there are pre-programmed courses in the simulator, a rider can also setup any ride profile he desires into the computer. Moreover, the PFS takes wind speed and direction as selected by the rider and transforms it in a way that gives realistic outdoor increases and decreases in wind speed which translates to a more realistic "windy" riding experience. As the wind is varied during the ride based on the model, the rider may feel necessary to shift into easier gears to pedal, just like in the real world.

After having built complete prototypes, all true and tested, Compton is now offering licensing of the technology.

In short, what is claimed by Compton is that the Pedal Force Simulator gets the instantaneous acceleration right. This affects the rider's ability to put power into the pedals and hence, captures real and subtle effects that one will never obtain on a trainer.

Thoughts and comments?

* * *

The AssBLEND® Bicycle Saddle

Apologetic Design Technologies
Gentle Avenue, Koala Bear 73232

Dear Customer,

Congratulations. You've made the right decision in purchasing our newly designed bike saddle, the AssBLEND®.

We at Apologetic have heard your needs and bring you a product that meshes perfectly with your ass like a fine fitting coat, better than any other saddle on the market. Do away with ass hatchets that leave you with a feeling of being violated by a leathered cantilever.

To ensure you have the best experience with AssBLEND®, we will guide you through your first baby steps with it :

1. When you first bought the AssBLEND®, you should have obtained a big airtight box with the name AssBLEND® printed on it in shining gold. If this is not present, you have not bought our product and we suspect its a Chinese knockoff.

2. When you open our big airtight box in anticipation using the tabs on the side, you will find a lump of material in it about 3 inches in diameter sitting in one corner. It has a blueish tint to it and may seem like a moon rock. At the other corner, there should be a steel spatula. Right in the dead center, you should have been able to find this instruction sheet you read now, neatly folded and kept awaiting the grace of your eyes.


3. Where the bloody hell is the saddle!, you'd have snapped impatiently by now. Ah. We expected exactly this question from our research. Patience now. Continue to step 4.

4. The blue lump/ball is pliable. Take it in your hand carefully. Feel the ball slowly. It is soft to touch. Yes feel it more. Ok, that's enough now...

5. This ball is a result of 5 years of research and design in our chemical laboratories at Apologetic. We have designed it in such a fine manner that it possesses a time dependent pliability for 5 min the moment it is exposed to atmospheric air at 14.5 psi.

6. Which means don't just stand there!

7. Please rush to the bathroom with the provided spatula immediately and strip off your trousers.

8. Close the toilet lid, place the ball on it at the dead center.

9. Now take a deep breath, try your best basketball jump and land right on the ball. Hold it there for exactly 20 minutes. The material is designed to work with human body temperature and hardens while expanding at the same time. While you wait, you can flip this instruction sheet in your hand for some testimonies from some of our customers. To give you comfort while you sit on the lump, we have made the testimonies (un)settling.

10. 20 minutes must have gone by now and you should feel something hard against the rear end. Take the provided spatula and scrape this hardened lump off your ass. Move onto step 11.

11. We forgot to say something in step 10. Please scrape it off carefully. That spatula is a work horse made by an artisan in South America so it can damage your ass with permanent marks if careless.

12. What you will observe on the spatula is a perfect negative of your rear end, containing an accurate description of all its crests and toughs, down to the most minutest details such as hair follicles, spores and childhood spank marks. Get your hands to work and do some additional shaping to get it into a saddle form.

One customer's sample has been provided below as reference.

Sample saddle in rough stages before processing

13. For final processing, what we call cold treatment, take any seatpost you would normally use, stick it into the AssBLEND® at the angle you desire and place into the your refrigerator.

14. After 1 hour of processing, what you should get is a rock solid copy of your ass attached to the seat post. Lock it in place on your seat tube with an allen wrench and off you go - yes, go...take your first ride with it.

Notice immediately as you ride, that every feature on your bottom melds into the AssBLEND® perfectly. What you've done is broken into the saddle with your ass in less than 2 hours. This is the AssBLEND® difference.


DISCLAIMER : Any product defect is not our liability. It's your own fault.

* * *

The G-G Diagram Applied To Bicycle Racing

In the midst of our world of possibilities for data analysis in cycling performance, I was wondering if we could consider extending our scope a bit to other things.

As we speak, more models of GPS systems, power meters and heart rate monitors are being designed and released with are basically just different answers to the same old questions : "what's my speed", "what's my power", "what's my heart rate".

But what about other fundamental questions and problems imposed by bike racing? How could we explore and quantify those parameters?

As an illustration, one topic for discussion rarely brought to the table in our daily techno babble is that of acceleration and its impact on safety. Acceleration is an elementary concept in physics and we all know how important it can be towards team race strategies we see today in cycling. Is it getting the importance it may deserve from an analysis standpoint? I'm not sure.

The question is : Could an acceleration analysis be helpful to the racing cyclist and how?

Consider a human-bike system in an Individual Time Trial, a bike race against the clock on a circuit of predetermined length and design. Often in a race of professional caliber such as this, the standard deviation of the data set of results from the top 5 placers is mere seconds.

While time trials are usually steady power output races, if we considered a very technical race course with lots of curves and S-bends, we could say that a majority of the racer's effort is concentrated towards finding the optimum line between the bends while controlling the bike's speed through braking and acceleration. Miscalculations here could cost seconds and a possible podium spot.

Consider two racers, A and B, who chose different paths around a section of this hypothetical race course. Let's also say that they were riding bicycles of the same design, with the same handling qualities.

Fig 1 : Paths of two cyclists in a section of an ITT course. COG = center of gravity.

Who emerged faster at the right end of this section? Racer A or B?

Of course, we wouldn't know because we don't have enough information, you would say. The information missing here is that of the cyclists' acceleration.

To maintain a curved path on the ground, any vehicle, be it a bicycle or a Formula 1 race car, must be moving sideways as well as forward. Hence, there are two components to the bicycle's acceleration. They are :

1. Lateral or centripetal acceleration (LA), whose vector points towards the center of curvature of the road. A bicycle turns because of applied lateral tire forces. LA is affected by tire-road friction characteristics, angle of lean, square of the speed of the bike and radius of the curve, R. If lean is too large (i.e. rider tilts too much into the circle), centripetal force will be too much and the bike will start turning into a circle with radius smaller than R. If lean is not large enough, there won't be sufficient force to keep the bike on the circle and the bike will veer off, turning in a circle with radius larger than R.

2. Tangential or longitudinal acceleration (TA), whose vector points in the fore-aft direction of the bike rider. It is decided by pedal torque, aerodynamic drag forces, and traction limit of the tires.

If m is mass of bicycle-rider system, v its speed along the course, R the radius of curvature of the curve, t is time and g is the acceleration due to earth's gravity, then the above two are defined mathematically in terms of g-force as :

The vectors of these components and their resultant roughly look like this :

Fig 2 : The tangential and lateral vectors of acceleration represented graphically. A reversal of lateral acceleration vector (purple) signifies reversal of direction while a reversal in tangential acceleration vector (red) signified reversal of speed with time.

If we attached perpendicularly oriented accelerometers at the center of mass of the rider-bike system for the 2 riders in Fig 1 , and if we captured lateral acceleration (LA) and tangential acceleration (TA) through a data recording system, the data points when plotted on a graph could look like this (shown just for illustration, not to be taken for granted).

Fig 3 : This plot shows an example g-g diagram (a composite of friction circles for both wheels) for two bicycle riders on the same section of the race course on the same bicycle. It consists of a forward acceleration, turning and braking regions. Data points for each cyclist is shown in red and blue. A rough boundary envelopes these points for both riders. It must be noted that the g-g envelope/boundary for each of the cyclists is not fixed and depends on the bicycle, maximum tire friction force, human skill level and environmental conditions imposed on tire-road contact. This is the performance envelope for the bicycle-rider system. Outside this safe envelope, racing a bicycle could be dangerous.

This plot is called a g-g diagram. The concept was described extensively by aerospace engineer and race car driver Will Milliken Jr.

The difference in riding techniques of the two riders resulted in two different maneuverability boundaries, which can also be looked at as the maximum potential of the rider-bike system in any technical section of the race course for the race conditions. A given individual can only generate limited g's of acceleration to get up to speed. Theoretical limits of deceleration are on the order of 0.5g for a crouched rider on level ground before a person flies over the handlebars. If they are riding two different bicycles with different handling qualities and tires, the g-g boundaries will be different in this case too.

The ultimate limit of the g-g boundaries is imposed by the acceleration capability of the bicycle, which is primarily determined by the grip between the tire and road surface. This is represented in the g-g diagram by the outer oval shaped boundary.

When a racer sits down and studies his g-g performance, he could get a graphical picture of how he utilized the components of acceleration at specific sites on the course and how his choice of equipment may have cost him.

With appropriate software, answers could be generated to questions such as : What's the range of my accelerations? Which direction did I spend more time cornering to? Did I decelerate too much before the sharp curves? Did I accelerate optimally after the apex? How much emphasis did I place on acceleration and deceleration? Could I have changed the ratios of these accelerations by riding differently and emphasizing various body movements? How would these have affected or improved my course times at the end? What really caused my wipe out at that sharp bend and was it related to the lean angle and speed with which I faced that bend? How does all this change with a change in my bicycle tires? Or bicycle design.

How may this be specifically applied to improve performance? I have some thoughts :

1) The tire and the bicycle could be engineered to widen the g-g boundary as much as possible throughout an expected range of operating conditions (load, surface, temperature) without bringing about potentially dangerous modes of oscillatory motion.

2) The rider could train and improve his skill level to ride and exploit these maximal g-g limits of his machine.

Perhaps knowing the performance envelope of the bike being ridden for specific operating conditions may also empower the cyclist with a feeling for when he can safely take risks to win a race.

Take a look at the following two videos. One shows the capturing of the acceleration vectors on a g-g circle for a remotely controlled toy car. The one below it shows what looks to be a real time friction circle generation from a computer simulation.

Its inspiring to watch these data recording and software applications. Perhaps we could have a neat cyclocomputer in the future that could show the bicycle's g-g diagram in real time, if its practicalities have been established. Maybe cycling commentators will start talking about g-g diagrams and other cool things in future race telecasts. Who knows. What do you think?







ADDITIONAL RESOURCES :

The G-G Diagram
Rate Of Cycling Uphill Explained
Wild Ideas For New Cycling Products Part 1
Wild Ideas For New Cycling Products Part 2

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Cold Forging Technology At Shimano

If you read descriptions of Shimano's products, you'll often come across the words "cold forged aluminum", mentioned with great pride.

Forging is a metal shaping process in which a malleable metal part, known as a blank, billet or workpiece, is worked to a predetermined shape by one or more processes such as hammering, upsetting, pressing, rolling and so forth. Cold forming is a precision category of forging which does the same thing without heating of the material (room temperature), or removal of material.

Most of Shimano's products in the bike and fishing business utilize cold forming technology, which was established by the company more than four decades ago. It was in 1963 that Shimano introduced a cold forging plant to press precision parts for bicycles using dies and high pressure in order to form metal at room temperature. Plants such as these use presses, punches and dies that see very high working pressures, upto 1500 N/mm^2.

But why such specialized equipment?

The plasticity of aluminum at room temperature is low. The flow stress of aluminum decreases with increasing temperature. For alloys that are very easy to forge, such as 6061, there is nearly 50% decrease in flow stress between 700 deg F and 900 deg F.

Forgeability and forging temperatures of various aluminum alloys. Note that 810-900 deg F is the recommended forging temperature for 6061 alloy. Credits : Aluminum and Aluminum Alloys (ASM International)

Therefore, at room temperatures , because the flow stresses are higher, large machines capable of ramming and hammering the hell out of these alloys to get accurate shapes are needed. Of course, its more a delicate operation as opposed to the violence I have described above as great care has to be taken to prevent microscopic defects from developing in the cold forged piece, while it works at the upper limit of its strength.

On the other hand, because cold forging allows one to make parts without introducing the need for heat treatment and additional machining processes, it is an economical manufacturing method to produce precision, net-shape parts.

This is exactly what was needed by Shimano back in the day when it started designing integrated shift levers and gears that demanded high precision but which invariably suffered from the disadvantage of having a specialized and small market without much economy of scale. It has been mentioned that Shimano is one of the few companies in the world that can produce cold forged aluminum parts with close tolerances as those needed in the STI mechanism.

So how exactly did Shimano get around to having this precision, cost cutting technology? It turns out that the company has to thank a brilliant electrical engineer who basically re-created the entire company in the 1950's by helping it adopt the cold forging process, way before any other company in Japan at the time, even Toyota!!

Shuzo Matsumoto joined Shimano in 1954 with a dream. A graduate of the electrical engineering department of Osaka Prefecture University, he saw his mission as introducing cold forging technology to the replace hot forging then used. To achieve this goal, he was dispatched to the United States for 2.5 months by the company President, Shozaburo Shimano (died in 1958). In those days, only a limited amount of foreign currency could be taken out of Japan by any individual. Therefore, before departure, he was handed a lot of dollars obtained from the black market by Shozaburo and was simply instructed to "enjoy the trip".

The following snippet from page 76 of the book "Japan : Moving Towards A More Advanced Knowledge Economy, Vol. 2 Advanced Knowledge Creating Companies " describes briefly how Matsumoto went about accomplishing his mission of introducing cold forging technology to Shimano. Zoom in to enjoy the read. If you've anything else to share about Shimano and their production processes, give me a buzz.

ADDITIONAL RESOURCES :

Cold Forging In Bolt Production : A Video From Discovery Channel's How Its Made
Shuzo Matsumoto Patent : Rear Hub With Built-In Three Speed Change Mechanism For A Bicycle

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