The weather was fine enough at the weekend to get out on my bike for the first ride with the SRMs fitted. It was meant to be a ride for comparing the accuracy of the Polar Power system with the SRMs, but I realised just as I was about to set off that I hadn’t fitted the cadence magnet that the Polar system needs to the SRM cranks.
The bike felt smoother with the new bottom bracket and cranks – I think this is a sign that the old BB needed replacing – it’s been on the bike since new (1997), so it’s lasted quite well!
The Power readings from the SRM seem to be a bit more consistent than those I’ve got from the Polar system, in that the numbers don’t seem to fluctuate quite so quickly, but it’s a bit difficult to tell until I get the cadence magnet fitted again. Also, there seemed to be a bit of variation in the HR readings between the two units, of up to 7 bpm at times, although this is most likely due to the higher sampling on the SRM compared to the Polar. Neither unit was consistently higher or lower than the other, just different.
One thing I noticed when I stopped for a gel was that the SRM will switch itself off after a minute-or-so of being stationary. One side effect of this is that the SRM shows the time for the journey as the actual time spent moving, whereas the Polar just shows the time from start to stop. Something that’s missing from the SRM is altitude readings – this means that you can’t really tell if a hard effort was due to climbing a hill or on the flat.
Hopefully, next weekend I’ll have the cadence magent fitted and get a decent comparison of the Polar & SRM systems.