Shopping For Climbing Power Or Speed

Gears Trade Climbing Power For Speed

From the seat of a stationary bike, it is easy to forget that setting the resistance up or down is analogous to altering the slope of the virtual hill you are pedaling.  When you pedal up-hill the pedaling is harder, and when you pedal down-hill the pedaling is easier.

Most real trikes & bikes have gears to trade climbing power for speed.  They have more powerful gears for accelerating and climbing hills, and less powerful gears for cruising and descending hills.  When you change gears up and down, you are trading between climbing power and speed.

Factors Affecting Climbing Power And Speed

First Factor:  A trike or bike may have any number of "chain rings" connected to the pedals.  The smallest is the "granny" for the most climbing power, and the largest is the "overdrive" for the most speed.

Second Factor:  The same trike or bike may have any number of "sprockets" connected to the drive wheel.  The largest is the "granny" for the most hill climbing power, and the smallest is the "overdrive" for the most speed.

Third Factor:  The "drive wheel" is a lever that pushes you forward when you pedal.  A shorter lever is more powerful but moves the load a shorter distance.  A longer lever is less powerful but moves the load a longer distance.  A smaller drive wheel has more climbing power over a shorter distance, while a larger drive wheel has less climbing power over a farther distance.

Fourth Factor:  Weight is the load that is moving.  When you accelerate, weight is the load whose speed is increasing.  When you brake, weight is the load whose speed is decreasing.  When you ascend up-hill, weight is the load being pulled up against gravity.  When you descend down-hill, weight is the load being pulled down by gravity.

How To Shop For Climbing Power Or Speed

First Step:  Decide whether you are focused on climbing power or speed.  If you are focused on climbing power then use the "granny" combination for the second step.  If you are focused on speed then use the "overdrive" combination for the second step.

Second Step:  Look up (or count) the number of teeth* on the chain ring, and on the sprocket.  Divide the number of chain ring teeth by the number of sprocket teeth to get the "Gear Ratio".

Third Step:  Look up the inches** diameter*** of the drive wheel (or use a tape measure to measure across the axle, from one outer edge of the tire to the opposite outer edge of the tire).  Multiply the Gear Ratio by the Diameter to get the "Gear Inches".

Fourth Step:  Look up the total pound**** Weight of the trike or bike (or weigh it on a scale).  Multiply the Gear Inches by the Weight to get the "Gear Inch Pounds".

Conclusion For Shoppers:  The Gear Inch Pounds is the load being pushed up every hill against gravity, and that gravity pulls down every hill.  The trike or bike with the lowest number of Gear Inch Pounds will be the strongest climber up hills.  The trike or bike with the highest number of Gear Inch Pounds will be the fastest descender down hills.

* Teeth used here since that is traditional.  The generic measure is circumference.  Any consistent comparison will do.

** Inches used here since that is traditional.  The generic measure is circumference.  Any consistent comparison will do.

*** Diameter used here since that is traditional.  The factual leverage length is the radius.  Any consistent comparison will do.

**** Pounds used here since that is traditional.  The generic measure is weight.  Any consistent comparison will do.