Triple vs Compact Crankset

I’m considering retiring my cherished 1998 Trek 5220  road bike. The biggest obstacle holding me back is that new bikes aren’t equipped with triple cranksets anymore. While I rarely use my granny gear, it’s comforting to know it’s there if I need it.

The bike I’m looking at has a double 50/34 (compact) crankset with a 11-32 rear cassette compared to my triple 52/42/30 crankset with a rear 12-26 cassette.  Before buying a new bike I wanted to know how much range would be lost if I gave up my triple crankset, so I did the math as follows:

High Range Calculation

Distance traveled with each revolution of the pedals in high gear =

Wheel Diameter x Pi x Largest Chainring/Smallest Cassette Gear

For example:
28 inches x 3.14 x 52 teeth / 12 teeth = 381 inches
28 inches x 3.14 x 50 teeth / 11 teeth = 400 inches

Here a larger number is better.
Triple 52/42/30 crankset with 12-26 cassette = 381 inches
Compact 50/34 crankset with 11-32 cassette = 400 inches

Low Range Calculation

Distance traveled with each revolution of the pedals in low gear =

Wheel Diameter x Pi x Smallest Chainring/Largest Cassette Gear

For example:
28 inches x 3.14 x 30 teeth / 26 teeth = 101 inches
28 inches x 3.14 x 34 teeth / 32 teeth = 93 inches

Here a smaller number is better.
Triple 52/42/30 crankset with 12-26 cassette = 101 inches
Compact 50/34 crankset with 11-32 cassette = 93 inches

I was surprised to find that the compact crank setup would give me a greater high range but I was downright shocked to learn that it would give me a better low range as well.

Ken Whittaker


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