A Shimano Solution To Toyota's Accelerator Problem

Dear Cyclists (& Pedestrians),

This is a notice.

Cozy Beehive is calling out a Worldwide Cyclist Death Or Possible Injury Alert For Immediate Make Officialling, also called WCDOPIAFIMO for short.

In the upcoming days, months and possibly even years, you will surely die or get severely injured out on the road if you don't stay away from something called a TOYOTA. Even worse, really old women with Toyota's. Now that can be even worse.


Steve Woz, the co-founder of Apple, has taken down many many individuals already with his Prius. Steve and his Toyota have both been arrested.

Meanwhile, we from the cycling community present Toyota's President Akio Toyoda with a temporary but bold suggestion to counter the car's recent misconduct on the road.

Mr. Toyoda :

All malfunctioning Toyota's should hereby be outfitted with Shimano Dura-Ace cycling pedals. Motorists have to wear Shimano's cycling shoes to clip into them.

The car is to be fitted with the same sensor technology that is installed in airplanes for stall warning. The Toyota's computer system, by way of an obnoxious Japanese voice, screams "Pull Up ... Pull Up!!!". Since the motorist's cycling shoes interface with the pedals, they can at once pull pedal with their feet to get the stuck accelerator back to neutral.

Shimano's carbon soles reduce excess weight needed to pull up with feet. Moreover, the carbon footprint in this forceful pulling up action is also small. All in all, an easy, green solution to a dangerous problem.

Thank you dear cyclists for reading this Worldwide Cyclist Death Or Possible Injury Alert For Immediate Make Officialling. And thank you Mr. Toyoda for considering this solution.

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Energy Costs Of Riding A Unicycle

A reader sent me an interesting page on the energy requirements involved in unicycling. Quite simply put, two riders, one skilled and one less skilled, show different efficiencies operating the cycle.

Skilled unicyclists devote more energy to going straight than they do trying to stay in balance through precise timing of corrective energy provision, while less skilled riders show the opposite scenario, which is why most of us lose out quickly and fall.

To keep a unicycle in balance, a correcting energy has to be supplied at some frequency for proper dynamics of the system. As far as steering is concerned, the main aim of balancing comes from steering in the direction to counteract a lean.

It will be interesting to study at what frequency skilled riders supply corrective energy to stay in balance. This is apparently done so that the small angular displacements lead to small energy expenditures. The estimation by the author is that 100 calories of energy is supplied by the rider per hour to aid in the balancing act.

Energy output per hour of various means of movement - bicycling, unicycling, walking etc.

The trick seems to be in finding the right balance between ranges for the angle of tilt the rider and his bike makes with the vertical. Too much an angle means you may go faster because of the squared relationship with gravity but it'll take more energy to raise your center of gravity up to the balance point. Too less an angle might mean you're perfectly in balance but you're moving slow.

I haven't ridden a unicycle but I'm wondering what you guys think. How do you balance yourself?

RELATED RESOURCES :

Four Part Series : Dynamic Stability Of Bicycle Design
Efficiency In Inefficiency : Walk Or Pedal Up A Steep Hill?

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Science Of Cadel Evans From Dr. David Martin

I happened to read an article in the Ride Cycling Review publication titled "A Study Of Champions : Cadel & Lance". This is an Australian magazine and I wouldn't have had the chance to read it were it not for partner in blogging crime, Wade over at Cycling Tips, sending me a fine copy from beautiful Down Under. Thank you!

Written by David T. Martin, a senior physiologist at Australian Institute of Sport (AIS) in Canberra, the article is a good reminder to all of us that some of the less talked about riders in the peloton also show remarkable physiological characteristics. Yet, few fancy documentaries are made on them.

Anyway, here's the basic information you need to know if you're ready to bust some myths among your cycling friends. Here goes :

1. Highlight : Cadel Evans posted brilliant fitness parameters at an age when he was developing as a cyclist. He boasts high VO2max and power to weight ratios, some of the highest ever recorded at AIS. His physiology, based on traditional measurements of aerobic capacity, reigns supreme over most cyclists, even Lance Armstrong. The article notes that while Cadel's aerobic capacity is higher than Armstrong's, no one has considered other top riders like Alberto Contador. Good point, Dr. Martin.

2. Sample Set : From a sports science perspective, a number of "fitness indicators" were established on Cadel Evans. He was tested more than 15 times at AIS between the ages of18 and 24 and the article focused on 7 tests at a time of the year when he was considered fit (between January and June)

3. How He Was Tested : Cadel was put on something called an electromagnetically braked ergometer to carry out the Australia national cycling team protocol. The procedure calls for 5 minutes of constant power output stages with a self selected cadence, where the initial power output was 100W and it was increased by 50W every stage until volitional exhaustion. The peak power output achieved during the test is calculated by adding 10W to the test score for every minute achieved in the final stage. Oxygen uptake, heart rate and blood lactate were measured throughout the test.

4. Results :Between 18 and 24, the best result achieved by Evans were :

Maximum Aerobic Power Output : 455 W (7.3 W/kg)
Threshold Power Estimation : 370W (6.0 W/kg)
VO2 Max Associated With Max Power Output : 5.65 L/min or 87 ml/kg/min

In those crucial years, Evans was characterized by Dr. Martin as :

62-68kg, 172-173cm; 380-455 W and 6.1-7.3 W·kg-1 at VO2pk; 4.59-5.65 L·min-1 and 73-87 ml·kg-1·min-1 VO2pk.
Economy (mean±SD; range) was 80.2±1.9; 77.5-82.5 W·(VO2 L·min-1)-1 or 401±10; 387-413W at 5 L·min-1 VO2.
GE was 22.6 ±0.6; 21.8-23.4% and DE was 23.6±1.1; 21.9-25.4%.

Now for you starters, power to weight ratio is the key variable for uphill cycling speed and threshold power output is an exercise intensity that represents a distinct transition from aerobic to anaerobic energy production.

Bottomline : Both Armstrong and Evans posted their best fitness values in their early 20's. At his best, Evans posted a power to weight ratio almost 8% higher than the 6.8 W/kg produced by Armstrong when he was 22. His highest VO2max was 7.4% higher than Lance's highest recorded value. Compare this, if you'd like, with Indurain's 6 W/kg at threshold and 7 W/kg at VO2 max.

4. A Word On Inaccuracies : Dr. Martin feels there were enough similarities in testing protocols and equipment employed to allow for an interesting comparison between the two athletes. Most interestingly, he has it in a paper on Evans that the data from his testing procedures did not reflect any improvements in cycling efficiency with maturation.

Recall that Armstrong's values stemmed from studies done by Dr.Coyle at the University of Texas, some of which, especially on the improvements in his cycling efficiency, came under fire from his peers for gross inaccuracies. Dr. Martin maintains that cycling efficiency calculations are very sensitive to equipment and are prone to inaccuracies. He did estimate Evans' cycling efficiency at 22 as 21-24%, similar to Armstrong's calculated 21-23 %, although he doesn't seem to put much faith nor emphasis on it.

5. Ending Quote From Dr. Martin :

"The data doesn't support the argument that Lance Armstrong wins because he was born with some god-given gift, some unique physiological capacity that makes his success as a professional road cyclist easy. There's a lot involved in winning..... Based on physiological traits, it is just a bit too simplistic - and a bit naive - to think that all of Lance's achievements can be explained by superior build."


So there you go. Just physical traits alone does not make you a winner. Moreover, years of training doesn't transform you into a freak of nature. Let's put folklore away and discuss just the facts.

Next, the Science of Alberto Contador. Does anyone want to volunteer from the Spanish Institute Of Sport or likewise? I suppose we'll have to keep the record books handy.

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52x12 vs 52x11 Gearing : A Look At Chordal Action

If you're the type who likes to gun it down the line in high gears, you may have wondered more than once - what is really better in terms of crankset chainring-rear sprocket size, would it be a 52T x 11T or a 52T x 12T?

At the same RPM, you get a slightly higher top end speed with the 11T at the sacrifice of some torque. But if you're asking this from an efficiency standpoint (ratio of input power over output power), its a slightly tougher nut to crack if you don't have actual measuring equipment.

I won't talk directly about efficiency but I'll talk about something else that you may want to start connecting, perhaps more with equipment durability than efficiency.

A bicycle chain has links, connected by a distance called pitch which is usually 1/2 inch in bicycles. When you're riding your bike at a cadence of 100 RPM, the chain has an average velocity called pitchline velocity. At the sprocket though, some interesting things happen with chain velocity.

For one link in your chain to engage a teeth in your sprocket, the link has to swing about an angle before the roller is seated between tooth. This is called Angle of Articulation, calculated by using the relation : 180/T, where T is the tooth count of the sprocket.


For a 11 tooth sprocket, the angle of articulation is 16.36 degrees, while for a 12 tooth sprocket, it is 15 degrees, a reduction of 8.3%.

Because the chain is turning at these sharp angles at the same time impacting the teeth, the velocity of the chain is not constant, but infact fluctuates between the maximum and a minimum each cycle. The maximum occurs before engagement, the minimum occurs after the link has swung in engagement. This change in velocity is called Chordal Action.

The point is that chordal action results in fluctuations in chain transmission and may be minimized by reducing the angle of articulation, which decreases with increasing sprocket size. For 11T and 12T sprockets, which are about the smallest standard sizes you can find in the bicycles, the angles are tight which results in uneven exit velocities.

But is it something you should worry about? The math is complicated to present here so I just did all the calculations myself elsewhere to look at chordal action. Perhaps you can decide whether it matters or not after looking at the following theoretical numbers.

Say you're riding hard at a cadence of 100 RPM with a 52 front chainring. The RPM at the rear sprocket is multiplied by the gear ratio, which results in 433 RPM with 12 T and 482 RPM 473 RPM with 11 T. With a 12T sprocket, one cycle of tooth engagement sees a 3.4% variation of chain linear speed, whereas an 11T sprocket sees 4.1% change in linear speed for the same because of the tighter angle the link has to swing.

Here are two graphs I generated :

Note : Chain velocity is a function of pitch circle diameter, RPM and articulation angle

What this does for transmission efficiency in bicycling is moot. What I wanted to present before you is the fact that chordal action is real in small sprocket sizes, and it has an effect on your tooth wear and pulsating motions at high RPMs. But it may not matter in low cadence (60 and below) and if you're using wear resistant, hardened sprockets. Feel free to discuss.



ADDITIONAL RESOURCES :

Dan Connelly : Drivetrain Losses

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Saturday Stupidity IX

While the geopolitical problems in the middle east continues on, another conflict moves on unabashed through the years.




We wish both riders good luck in their senile competition. Love him or hate him, Armstrong is doing will do plenty for Acne.



FOR PREVIOUS 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

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