My quest for the most comfortable bike is designed to be as objective as possible.
It all started with the mobile phone (Huawei Mate 10 Pro) and a Vibration meter app that uses a phone accelerometer to measure, as the name suggests, vibrations. The less overall vibration score measured in m/s2 the more comfortable the ride should be.

The ride that I measure contains 2 different scenarios.
First is a forest path with a lot of tree roots and different big and small bumps. It measures 720 meters and it emulates a challenging gravel riding (but not true singletrack because I believe that gravel bikes are no mountain bikes and should not be measured in MTB conditions).
The second is a true gravel road with only very small bumps and rocks. It measures 350 meters and I use it to emulate gravel racing.
The first route is more challenging that is why I measure the vibrations while going at steady 15 km/h on average. The second route is used to emulate a fast gravel riding that is why I go there with speed around 35 km/h.
I do at least 3 runs always in the same direction and following the same route. If the measurements are very similar then I calculate the average. If there is an odd measurement I discard it and go one more time. Most of the time 3 runs is enough, especially on slow forest runs (the fast gravel route is producing much more vibrations so sometimes the results may vary more).
I measure both the front and the rear comfort of the bike.
To measure the front I ride on the hoods (to put more weight on the handlebar that will allow more flex from the handlebar and/ or flexing stem) with a phone mounted as close as possible to the wrist just to minimize the impact of the arm movement on the final readings.
To measure the rear I use a belt mount and put the phone on my back on the aitchbones level (this measures the vibration just above the saddle).
To get the most comparable results I always use the same phone mounts, the same phone and app, the same bike saddle, the same bike shorts, and the same Giro Bravo gloves (because I am riding on hoods I do not take bar tape into consideration). Before the test, I always try to achieve the most similar bike position (saddle height and saddle position most appropriate for my body and my inseam length and I try to stay seated in every situation which sometimes can be even harmful but hey, I do this for the science!). And my weight… is rather stable at 83 kg 🙂
As you can see, my measurement procedure is designed to achieve the most accurate results possible in real-life situations but, despite my efforts, you have to remember that this is not a scientific lab measurements. This means two things:
1. You should not compare the results achieved in significantly different scenarios. For example, if I tested one bike in summer and other in winter, we can’t compare the readings between them. What we can compare and what I always do, is to see how tested bike (or a tested bike part) compares to the benchmark bike (benchmark situation) tested in the same scenario, in the same weather, etc. For me, this means redoing the measurements on my benchmark bike again and again for each new bike or bike part test, but I am doing this because I want to be sure that I am comparing “apples to apples”. And that is why I do not publish anything like a leaderboard where I would have to compare readings done in different scenarios.
2. Measuring vibrations via the mobile app means that the results are strongly connected with the accelerometer put on my particular phone. So while I can compare the results made by my phone, you should not try to refer them to the results that you, for example, got on your phone. As I said, this is not a scientific measurement per se and it is not the most accurate one which means that difference below 5% should be read as a marginal in terms of real comfort difference. Everything between 5 and 10% is a modest but perceptible improvement and difference above 10% is a strong indication that there is a real and substantial distinction in comfort between tested products.