Tilt calculation

[AussieDon]

My PP profile for my Specialized Roubaix (2015 has a riding tilt of -3.6 which is perilously close to being out of range. I did have a ride recently where the tilt went over -4 so I couldn't adjust my profile using that ride if I wanted to.

There isn't much of a discussion in the May 2020 edition of the Isaac User Manual and some references to tilt are on pages that refer to the Newton device so I'm not sure if the documentation is relevant to the PowerPod.

The only explanation I could find was on page 45.
10) Generally, a rider’s weight on the bike will cause the red line (uncorrected tilt) to
slope downward. In this example the average slope of this “riding tilt” line is -0.3%.

Is such a large negative tilt an indication of a setup or calibration issue? My device is as level as I can get it but does that tilt value suggest that it needs to be rotated up a bit? The other values in my profile seem reasonable.

What does a tilt of -3.6 mean in real life?

Thanks

[Velocomp]

When you do a cal ride the tilt value is set. The value is an internal parameter that has no corresponding meaning to the external world.

It is nothing to worry about.

[AussieDon]

Sorry to belabor the point, but if the tilt can go out of range on an out-and-back ride, there must be some real world influence on that internal value.

On the ride that went out of range, I recall that the tilt went to -4.2 when I tried to analyze the calibration. I guess that's my main concern with my tilt being so close to the threshold. If there are 'significant' changes to be made to my profile after a ride, I wouldn't be able to apply them due to the tilt being out of range. I don't want to fiddle with it by editing the profile but I would like to be able to refine the profile I've got.

I do take the point that constantly fiddling with the profile is counter-productive and once I dial it in, I'm sure it would not need much tweaking....

[lorduintah]

Hey - Have you tried experimenting by moving the entire mount one way or the other and doing a cal ride, etc.? Your vision of level may be a mistake - of course not dismounting the PP between rides helps. What exactly are you using to gauge the PP is "level"? Is the ground under the wheels level at the same time?

[AussieDon]

I mounted the PP in the living room of my apartment and the floor is level. I tried checking it again with a digital level but there is no horizontal line on the PP V2 so it's hard to be sure that I had the level exactly level with the bottom of the lettering on the device. Given there may be a margin of error there I put the difference from level on my PP at about 3.5 degrees rotated up.

The PP installation instructions say to make sure the device is approximately parallel to the ground so I think that's probably falls within that definition. John did say that it was nothing to be concerned about and I'm not keen on repeating cal rides because I have to ride out of town about 10 km to find a suitable road that's not too hilly or busy.

John>If that measurement is actually not within the tolerance of the device, I'll gladly adjust the position and do another cal ride to see if that changes the magical tilt number.

[Velocomp]

A new cal ride will adjust the tilt calibration value.

The easiest way to "set and forget" is to keep your unit attached between rides.

[Kcblair]

A new cal ride will adjust the tilt calibration value.

The easiest way to "set and forget" is to keep your unit attached between rides.

What about us, that move the unit between 4 bikes, as the unit is designed to do ? When I switch between bikes, I try to level the PP , using bottom of the letters as a guide. Power numbers seem to be consistent between bikes. KB

[Velocomp]

Yes, everything should be fine, just the way you are doing it.

PP will automatically figure out any corrections that need to be made.