F430 pic from Wikipedia - pretty, isn't it?

As a followup to Part 1, a question for you;

Are you a Ferrari or a Peterbilt?

I have a friend, a very accomplished cyclist, who fancies himself a Ferrari. To look at Eddy you'd have to agree; he's long, lean and very sharp looking. But to ride with him may have you thinking more Peterbilt, than Ferrari. You see my friend is very strong and rides with a slow, powerful cadence. Many who ride with him remark; "the guy never shifts... he did the whole ride in one big gear."

I'm finally continuing with this series, comparing the athletes in your class with the engine in their cars.

Let's explore the difference between small displacement > High RPM engines found in High Performance Sports cars and the large displacement > low RPM engines found in a Semi Tractor- Trailer or Lorie you see running down the highway. Then see if we can draw a a few correlations between them that would be interesting to the Gear Heads in your class... after all, if your class is anything like mine, you're beginning to see more men, now that it's getting cold outside.[wlm_private 'PRO-Platinum|PRO-Monthly|PRO-Gratis|PRO-Seasonal|Platinum-trial|Monthly-trial|PRO-Military|30-Days-of-PRO|90 Day PRO|Stages-Instructor|Schwinn-Instructor|Instructor-Bonus|28 Day Challenge']

The F430 Ferrari is an incredible car. It will go zero to 60 in 4 seconds, a top speed of 200MPH  and you can get one of your own for only $200,000 US. What moves this 3,200lb rocket, when you push on the "fly by wire" accelerator pedal, is a 4.3 liter gasoline engine that develops 483 horse power - once it is spinning at the maximum of 8,500 RPM.

A conservative choice for an engine in your new Peterbilt truck is a Cummins ISX15 diesel engine. This engine makes 485 horse power while turning a leisurely 2,200 RPM

So the F430 and the Peterbilt both have essentially the same horsepower (483 vs. 485) available to the driver.

What's the difference? Isn't Power... Power?


The Cummins engine creates 1,850 Ft Lbs of Torque, over 5 times that of the F430's puny 343 Ft Lbs, while only turning 1/4 the RPM. The Peterbilt needs all this Torque to move the combined tractor and trailer weight of a 50,000lbs up over a 6% grade. To create that Torque the Cummin's engine is massive (weighing over 3,000lbs - about the same as the whole F430) with huge pistons that are (you guessed it) about 4 times as large in diameter!

Torque in an engine is created by the force of combustion acting on the surface area of the piston. While there's a lot of other physics that go into the creation of Power, I'm reminded of an old racer's adage that goes something like; There's no replacement for displacement.

What's true in engines is true in humans... with all other things equal; bigger muscles can create bigger forces = more Torque. But Torque doesn't get you up the mountain - that's Power. So of two women of equal weight, the one with the biggest legs doesn't get to the top first.

The winner to the summit will be the one who can continuously make the most Power, for the duration of the climb.

My buddy Eddy, like most endurance athletes, is a student of himself. Over 10's of thousands of miles, he's learned exactly where his body makes the most Power, the most efficiently. In his case, he understands that his very strong legs work best while powering through at what many would say is too slow a cadence.

Fans of the Tour de France may remember the climbing battles between Lance Armstrong and Jan Ullrich - where the contrast between Lance's 90+ RPM and Jan's 60ish RPM had them climbing at the same speed = they (I'm assuming they have similar body weight) made the same amount of Power. The same Power that is, until Lance turned, looked, then accelerated to 100 RPM and dropped Jan due to his superior Volumetric Efficiency - ability of an engine to process Oxygen, by efficiently moving air through itself.

After all Lance Armstrong is truly a Ferrari - but that's a subject for another post.

A fun class you can offer (if you teach with Power/Watts) is to create a profile that includes a series of laddered efforts of increasing cadences - while maintaining a set percentage of FTP or some baseline wattage. The purpose of the class is to help each student find the RPM range where they are the most efficient, i.e are they a Ferrari or a Peterbilt?

Amy and I experience this every time we ride our Tandem. In His, Hers and Ours Audio PROfile we explore how different cadences can be used to create the same amount of Power, or ground speed, which is essentially the same thing.

You may choose to use only RPE or you could tie each step to a HR. Maybe you cue wattage as a multiple of body weight; Now everyone find their One Watt Per Lb wattage at 70 RPM. Now let's add 10 RPM and reduce resistance to stay at that wattage... after 3 minutes ask, what's the result? Do you feel like you are working harder? HR higher or lower?

This might be a fun exercise to use a few weeks ahead of an FTP assessment - where we first teach everyone their Natural Cadence (best efficiency) and then have them ride at that RPM during their assessment.

Sounds like a question for Cameron Chinatti - stay tuned...[/wlm_private]



Originally posted 2012-10-02 10:00:00.


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