marcag wrote:
Funny you bring this up.
I wanted to try this
I have a very reliable Quarq, very reliable powertap, very reliable computrainer and 2 identical rear deraillers one with CS pulleys, the other stock.
I have a chain quick release
So I planned to
a) program a ERG workout, something like steps of 5minutes, adding 10watts every 2 minutes, go from sa 150 to 300, 15 steps, 2 minutes each
b) record CT, PT on rear wheel and Quarq on crank
c) remove chain, swap derailleur, put back chain
Probably do this on different rear cogs, say every 2
Better ideas ?
Well I don't know that you need to make it that involved. I roller test tires using just a powertap and a set of rollers. I get really repeatable A-B test results just hopping on and riding each tire for 2 to 3 minutes holding a constant speed (24 mph is what I use. I test on a rest day and it only takes about 130 watts to hold on the rollers. Maybe it should be called "rest and test day").I just started I have screen on my Garmin with 3 second and average lap speed.
For a first try I would just choose a single gear and ride that for 3-4 minutes at a constant speed and cadence. The amount of chain has to bend to travel around the gear varies by gear and there could be difference in friction if you chose different gears.
The one thing that does make a difference is making sure the tires are up to their operation temperature. You can see the wattage drop on the ride graph as the tire warms up until it reaches an equilibrium point for my chosen speed. There could/ should be a breakin period with a chain, especially if it is newly waxed. Same goes for the lube in the jockey wheels. You might want to go 10-15 minutes as a breakin with each setup to make sure each has stabilized.