I decided to write this story, and I just wanted to share my experience with you. Why post it on this forum, you might ask? Just because I want to tell a story, and maybe someone else might be able to benefit from it with a similar issue.
In terms of advanced spindown calibration (factory reset), this applies to both Wahoo Kickr and Snap. If you are not here for the story, and just want to skip to the method, it is the second link referenced in this post.
I have been using the indoor trainer, and I have been questioning the power output reading from the trainer for a few weeks. Like everyone else, I have been on the indoor trainer a lot more recently, and I have been enjoying the Trainer Road training plan. I am also trying out group rides and races in Zwift as well. Naturally, all of my friends are following the same indoor experience, and when they see the numbers on my Strava, they questioned the numbers. I had a similar comment made by several different people. They all said that “the power on the trainer seems low.”
So here is what I did. I looked up online and forums to see if other people are having the same issue. No luck. At this time, I had trust in the equipment, so I thought the problem is with me being a beginner cyclist, so I searched even more with a different angle for an explanation. I also looked up about the endurance muscles takes some time to build, and the low number reading is not the trainer issue. I thought I WAS the problem. It is very easy to blame other things because naturally, it is hard to admit it. haha
At this point, I needed a different data points, but I don’t have any other power reading reference point. I had no idea how to connect the effort I put outside and the power reading in watts. I trusted the trainer more than my endurance ability. Finally, I decided to convince myself that if the number is inaccurate but consistent, then over time, I will grow as a strong cyclist. I told myself, “don’t compare the numbers with others.” That seems the mental mindset we have here at Trainer Road.
Well, that only worked on weekdays when I am on the training plan. As soon as I am riding with friends on Zwift, I got discouraged how slow I was going, and I needed to find an excuse to tell myself!!
I searched some more, and of course, I didn’t find anything. DANG it! I was so desperate for an explanation. I needed a valid reason. ANYTHING! Just please tell me that the trainer is reading the wrong output. BUT, even after multiple attempts for the trainer calibration, nothing seemed to work. (going back to accuracy vs. precision)
That is when I started to suspect about the history of the trainer. Hold on… I thought to myself, “maybe the previous owner did something to the trainer to change setting/configuration, and that’s why the power output reading is low.” Well, at least that was my hypothesis, and I wanted to test if my assumption is correct.
So now, it seems appropriate to talk about the relationship with my trainer. Hold your horses. The result of the hypothesis will come. Just hold on. Haha
Let me just layout that I bought my Wahoo Kickr used in Nov. 2019. I wouldn’t lie. I had spent so much time considering about purchasing the trainer. Boy, oh boy, I am happy that I have invested in this trainer. I was debating to buy either an indoor trainer or a power meter at the time, and I found a good deal ($550 used), so I bought it. I thought I was purchasing the latest 2018 model, but later I learned that it is a 2017 model despite the owner mentioning that he bought it in early 2019. Darn it. This link would give you a general idea of the model Wahoo Kickr you have: https://zwiftinsider.com/wahoo-kickr-versions/ If you are considering buying a used one, I would recommend checking it. I looked it up, and I still failed to identify it correctly…
Anyways, back to the hypothesis. I learned that in addition to routine calibration, there is another way of doing the calibration: Aka, a factory reset. I searched for a method for a factory reset. I didn’t even know if there was such a thing, or it would help the issue, but I had to give it a try. Then, I found an article explaining how to do a factory reset. Advanced Spindown Calibration on Wahoo Kickr and Snap: https://www.smartbiketrainers.com/advanced-spindown-calibration-wahoo-kickr-snap-4350
The article explains about two types of calibrations:
Normal Spin Down
Advanced Spindown Calibration
So if you are interested in doing the advanced spindown calibration, scroll down the page to the second part. I followed the instruction for this advanced spindown calibration.
There are two parts. In standard calibration, you are asked to spin the trainer for 10 minutes before any spindown calibration, but in this advanced mode, you are asked to turn the trainer for a few more minutes on top of the initial 10 minutes warm-up before it starts.
After the warm-up is done, the first part is the same as the usual procedure. Spin up the trainer to a certain speed, and then stop pedaling. Once the pedaling is done, the trainer slows down naturally due to friction in the system. I believe that they measure the internal resistance (friction) in the drive train such as bearings and the belt.
Then, the instruction asks you to spin the trainer again to a target speed again. Once the trainer hits the target, you are asked to stop pedaling. This is the part that is different than the normal calibration process. This time the trainer slows down a lot quicker, and I believe this is where the trainer is calibrating the brake force applied by the trainer.
After the calibration was done, I double-checked, and triple checked that the trainer is indeed calibrated on Trainer Road app and Zwift. I didn’t have the time to test the result to see if the reading is different.
The next day, I had a 90 minutes workout on Trainer Road, and I tried a group workout (this is another topic to discuss on its own). This is the first week of SST II on low volume, and I did my ramp test 4 days ago, so I was expecting this work out will be a tough one!
BUT, it wasn’t… hmm, maybe the power reading was lower, and the calibration worked.
At this point, I know what you would suggest.
“Repeat the ramp test and adjust my FTP accordingly.”
Absolutely Right. Well, I didn’t… After the workout was done, I had a zwift ride with friends in 30 minutes. Ok, right. I know what you are thinking… “Technically,” I could squeeze in the ramp test, and then go on the group ride. Well, yes, you are right, but I wasn’t that eager. Haha.
Anyways, before the calibration, I was having a hard time sustaining 2.1 w/kg for 20 to 30 minutes, and it drops down to 1.8 w/kg for 2 to 3 hrs. Then, after the calibration, I was sustaining at 2.9 to 3.0 w/kg for 20 to 30 minutes and 2.6 w/kg for an hour. (I had to double-check my rides on Strava to make sure that I am not exaggerating it.)
I have to be clear that the “before calibration” number comes from a ride that lasted for 3 hours without the rubber band effect, and the other is for only an hour with the effect on, so my pacing might be different plus maybe my speed is biased. BUT, I felt much better as I was able to keep up with friends and be in the part of the first group. At the end of the zwift ride, I saw a significant increase in my FTP, and that was the moment I said, “YES!!!” in my head. haha
Obviously, now I have to do the ramp test to adjust the FTP on the Trainer Road.
For a reference, below are my current stats:
Weight: 127 lb (57.6kg)
Height: 5’10” (177.8cm)
09/05/2019: 99 (virtual power on Trainer Road) 1.7 w/kg
10/29/2019: 127 (virtual power on Trainer Road) 2.2 w/kg
01/23/2020: 135 (Kickr on Trainer Road) or 2.3 w/kg
04/14/2020: 144 (Kickr on Trainer Road) or 2.5 w/kg
04/19/2020: 168 after factory reset (1hr ride with the rubber band on Zwift) or 2.9 w/kg
So the FTP increased to 168 from 144, which is about a 17% increase.
Well, this is not the end of the story. There is more! During the weekend, I did my first VO2 Max workout, and I barely had my heart rate going up. Ramp test! Do the Ramp test!! You might be thinking… well, again, I didn’t do it. Instead, I tried a crit race on Zwift, and oh boy, the experience in category D is so different!! After the race, I got another bump in FTP to 206 from 168 (3.6 w/kg from 2.9 w/kg). Well, I am totally disqualified in category D, but that is another 23% increase or a 30% increase since the reset! I am happy, but another doubt crosses my mind. Am I cheating somehow without knowing it…? Is this number really accurate…?
Well, I think I will keep this as is and go back to accuracy vs. precision mindset. As long as I don’t change the setting drastically, I should be growing. I might just end up getting a surprise when I ride outside.
Thank you for reading this far. I hope you enjoy reading this, and let me know what you think or leave any comment, please. If enough of you are interested in reading, I might update it with the result of the ramp test. haha