In the SRM documentation it says that the SRM PM9 works with ANT+ or Bluetooth, but then it has a contradictory statement saying the Head Unit must have Bluetooth for the SRM PM9 to work. Has anyone pair the SRM PM9 to a Head Unit like a Garmin 500 that does not have Bluetooth?
It will work, the PM9 broadcasts in the ANT+ PowerOnly protocol.
Thanks, I called SRM and the person didn’t sound confident in his answer but said it would not work with an ANT+ only head unit because it would not work with their older ANT+ only SRM head units.
It will work, the PM9 broadcasts in the ANT+ PowerOnly protocol.
Thanks, I called SRM and the person didn’t sound confident in his answer but said it would not work with an ANT+ only head unit because it would not work with their older ANT+ only SRM head units.
Like you, some months ago I had a conversation with a SRM guy, but he was a competent one at the headquarter in Germany, knowing all technical internals, and I could talk to him in German.
I wanted a track PM. He explained to me that SRM has turned to the ANT+ Power Only protocol (the ANT+ protocol every bike computer and every powermeter with the ANT+ logo on it should understand) with the PM9. SRM kipped their Crank Torque Frequency (CTF) protocol with the PM9. I than ordered an “old†PM7 for a good price, because I very much prefer the Crank Torque Frequency protocol.
The SRM head units up to the PC7 understood only the SRM CTF protocol. The PC8 since about 2016 knows every ANT+ power, speed and heart rate protocol.
Thanks, I called SRM and the person didn’t sound confident in his answer but said it would not work with an ANT+ only head unit because it would not work with their older ANT+ only SRM head units.
Like you, some months ago I had a conversation with a SRM guy, but he was a competent one at the headquarter in Germany, knowing all technical internals, and I could talk to him in German.
I wanted a track PM. He explained to me that SRM has turned to the ANT+ Power Only protocol (the ANT+ protocol every bike computer and every powermeter with the ANT+ logo on it should understand) with the PM9. SRM kipped their Crank Torque Frequency (CTF) protocol with the PM9. I than ordered an “old†PM7 for a good price, because I very much prefer the Crank Torque Frequency protocol.
The SRM head units up to the PC7 understood only the SRM CTF protocol. The PC8 since about 2016 knows every ANT+ power, speed and heart rate protocol.
What’s the advantage to sticking with the SRM CTF protocol over going with the new ANT+ Power only protocol? Is it the ability to statically calibrate the PM with weights with the CTF Protocol?
With power only one is restricted to a time controlled ~1 Hz sampling rate. Power only is a black box, the receiver just gets the processed power value in Watt. One doesn’t know if or when a tare was done … .
With the event controlled CTF and a SRM track PM the sampling rate can go up to ~ 4 Hz. A dedicated receiver can process the higher sampling rate (for example a WASP for velodrome aero testing) and hence one has better synchronization with fast speed sensors. The slope and the tare / zero value is / can be stored on the receiver, thus one has control over it. CTF is closer to the hardware, it is only a grey box.
Cheers.