2012-10-6 Powertap SL+ Static Torque Test

As noted in my last post that I thought my Powertap hub might be off a little based on the torque offset value of 526 posted on the Garmin 800 just before riding this morning and also each indoor training session was at 529. I thought maybe I would also do a rough static weight test to check as well. Some would call this a "stomp test."

Here are the two links showing how I have done the test in the past.

http://thecyclingaddiction.blogspot.com/2010/05/powertap-torque-test-rough-initial-test.html
http://www.thecyclingaddiction.blogspot.com/2012/01/2012-torque-test-garmin-800.html

The weight (52.8 lbs.) is not actually a certified weight so that has to be considered for reduced accuracy and the bike and crank arm (170) was held in a constant near level position so that has to be considered for reduced accuracy.

 The cassette is a SRAM 11-28 and the front ring used is a SRAM Red Compact 34.
 The head unit is a Garmin 800 that give a torque value in newton meters and has to be converted to pound force inch to be used in the equation shown on the link above.

11 cog - 5.63% error
13 cog - 3.18% error
15 cog - 3.83% error
22 cog - 3.00% error