Quarq offset change after battery swap

Equipment
1

Anyone else have their Quarq zero offset numbers move around after swapping out the battery? This morning my meter wouldn’t pair before starting the ride and had no LED, so swapped the battery out and it came to life. My zero offsets have almost invariably been -71/-72 lately. After swapping the battery and running offset several times over a few minutes, it fell to -69, -65, -62, -61, then finally settled on -59. I checked it a couple more times during and after the ride and it was around the same.

This is really messing with my head. After 2x20 and 3x15 SST recently feeling somewhat challenging, the 2x25 that I was dreading this morning felt fairly manageable, despite riding at equal or greater power than I’ve been doing lately. My HR seemed to suggest that I was working at least as hard as the power would suggest, but RPE felt lower. Maybe I just had a good day and it’s all in my head? Should I be concerned that my offset moved around and maybe the gain moved around too? Maybe I need to retest FTP soon?

2

Doubt you need to worry. The offset is an internal calibration figure. It works by measuring the electrical resistance via strain gauges, and so the declining voltage on a dying battery could easily account for it even if no other physical changes occurred to the setup (chain, bottom bracket maintenance, chainring swap).

Further, the change +10 is only ~1/3 nM, which is fairly small (each offset point is 1/32nM). With just slight bumps to the frame you can get that kind of a reading. While riding you’d be putting out torque figures of 20+ nM so a 1/3 nM change is in the realm of measurement error.

1 Like
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Totally normal. New battery = new offset.