Gear Comparisons

When buying a new 29er bike I wanted to see how the gears compared to my 26” bikes.  This simple spreadsheet allows you to enter in the details for the 2 bikes and see how the gear ratios compare.

Gear Comparison Spreadsheet

It can be used to compare a road bike with an MTB, 2 road bikes or 2 MTBs.

The important parts are the figures for the top and bottom ends of the full range.  The number of feet travelled per pedal revolution in the lowest and highest gears.

To download a copy of the spreadsheet in Excel 2010, click on the link below. Alternatively email me at Nerdy@sterry.org

NerdyGearComparisons.xlsx

Simple Cadence Meter

Turbo training can be tedious at times, especially when you have little feedback about your performance.  The elaborate bike computers can be expensive so here’s how to make a Cadence Meter on the cheap. 

All you need is a spare bike computer that can measure speed.

1. Tape the magnet that would normally go on the wheel to the left hand pedal crank, near the end with the pedal.
2. Fix the sensor to the bike frame so it can detect the magnet on the pedal crank.  Use cable ties to hold it in place. Fit a small piece of inner tube between the sensor and the frame to stop the sensor from slipping.
3. Fix the bike computer to the bike frame where you can see it.  Some cables may not be long enough to reach to the handlebars, so you could mount it on the down tube.
4. Check that the cable is kept out of the way from the pedal movement.
5. On the bike computer, set the speed to km and the wheel circumference to 167cm.  This gives the critical measurement for the cadence meter.

As many bike computers can’t display speeds over 99.9mph (understandably), the cadence display is divided by 10.  Therefore a cadence of 85 will be seen as 8.5 and a cadence of 115 will be seen as 11.5

Now you can get pedalling and know how fast your legs are working.