Cadence Changes Necessary in ERG mode?
Before my issue, let me first highlight my indoor set up: KICKR18 and Quarq powermter; I run TrainerRoad on my iPhone with my Quarq and KICKR18 as the power sources (KICKR set to ERG mode); TrainerRoad is set to automatically PowerMatch which neutralizes any offset between the two.
During the intervals when I'm in ERG mode, I've found myself having to shift (up or down) the rear cassette to make sure I maintain the stated power. Today's long sweet spot intervals are a good example. The target was 200 watts and I selected a cadence of 95 RPM to do that interval. A couple of minutes into the interval I found that I had to shift to harder gears to maintain the watts even though I was maintaining 95 RPMs. I was giving TrainerRoad ~5-10 seconds to catch up to see if the power would stabilize and it did not. It eventually got to where I was over 100 RPMs and in the 11-tooth in the rear cassette to maintain the target watts. Past experiences have been consistent where my pace and power were steady but I've had to shift to maintain target watts.
Does anyone else have similar issues in ERG? I've looked through the TrainerRoad forums and it is an issue some have mentioned, but without any resolution.
Also, at times I will also have Zwift running in the background, with my Quarq as the power source, but "uncontrolled" in the Zwift settings. With either option, TR stand alone or TR/ Zwift combo, I've had the same experiences.
Comments
Interesting. That should not happen in ERG. I have a similar set up using TR but with an Android phone, Garmin Vector PM and Kickr Core. I have not experienced your issue. I never have to change gears while in ERG to maintain a specific power or cadence. Try this to shed more light onto the issue. Run Zwift in the background but with your Kickr as the power source, uncontrolled. Then during your workout monitor the power differences between Zwift (Kickr) and TR (Quarq) and continue to monitor and compare watts when you find yourself having to shift gears to maintain stated TR power. You Quarq power readings could be a lot higher than Kickr's causing TR to reduce the resistance.
Another change you can try is to have your PM/Kickr communicate with TR via ANT+ only. This might mean running TR on your Laptop. If you're already using this set up, try switching everything to BT. Not sure this will make a difference unless there's some type of interference affecting ANT+ or BT.
I hope this works, but let me know if and how this gets resolved.
Thanks @Derrek Sanks , I'll try what you said and let you know.
@Jeff Phillips
I see the same thing. I usually start a longer interval at a higher cadence then shift and finish with a slightly lower cadence. IMO its a function of how you are applying power (torque) to the pedals or power meter. It takes a real focused effort for me obtain an even power number with the same RPM for a full interval. Usually the cadence stays high but the power drops because I'm fatiguing and my form isn't the same.
I noticed the same feeling on my old "dumb" trainer as I do now on the kickr. Since the function of ERG mode is to "force" you to hold a certain watt level you are noticing it more.
@Derrek Sanks @Mark Stahlkopf I was able to figure out a solution to the problem I was experiencing.
I performed an advanced calibration/ spin down from the Wahoo app to calibrate the KICKR's brakes. Below is a link to the site. Note, the advanced spin down is on the bottom half of the page.
How to Do An Advanced Spindown Calibration on Wahoo KICKR and SNAP | SMART Bike Trainers
https://endurancenation.vanillacommunities.com/home/leaving?allowTrusted=1&target=https%3A%2F%2Fwww.smartbiketrainers.com%2Fadvanced-spindown-calibration-wahoo-kickr-snap-4350Once I did this I was locked in ERG for today's 2 hr 15 min session.
I appreciate the advice you all provided.
Thanks for the information Jeff. I'm going to bookmark this page.
I'm glad you found a solution.