My bike setup has SRM power. I am given the choice of whether to pair with my Wahoo trainer or my SRM. Does it matter? Is one preferable over the other?
Thanks
Sometimes the power output between any two power meters may vary. If you do see a difference between the two, you may want to pair it to your SRM to have it be consistent with your outside rides . I have a Stages and see about a 20 watt difference in power, which isn’t small. If the difference is marginal it may not matter for you. You may also want to monitor how quickly both seem to pick up an uptick in power to your pedals. My Stages seems to pick up a little faster than the Wahoo does.
Generally the closer the gauges are to the actual force, the less loss there is. May be a slight issue in race scenarios but I assume the differences we are talking about is fairly small. I also remember hearing that some trainers respond faster or slower than others. Like the previous post said, his Stages reports changes more quickly. I notice the same thing with my Pioneer. My Pioneer picks up a sprint sooner, peaks a little higher, and drops off faster (which makes sense since the trainer wheel is still spinning after I stop pedaling but my cranks don’t feel the increased force anymore).
But if you are training, just be consistent with what you use. Setup your bike properly (follow trainer setup instructions, use 0 offset or spindown or whatever it is called as needed, use a consistent PSI on tire, etc). Keep your firmware up to date (not to mention drivers on the computer) for your meter and/or trainer. And keep the setup as consistent from day to day as possible. That way, as your power increases you know it is you getting stronger and not just that a wheel on trainer has the tire PSI off a bit, the flywheel tightened a bit more or less, haven’t done a spindown in a month, etc.
Personally I like using the same power meter all the time and don’t care about using ERG mode in Zwift (cannot use non-trainer power meters for ERG unless that has changed recently). So I use my Pioneer for power data while in Zwift. That way, I make sure that changes are not simply a matter of which power meter I am using. My pairing is Pioneer for power and cadence. And Wahoo Kickr Snap for controllable trainer. Only thing I cannot do with that setup is ERG mode in Zwift. But that isn’t a huge deal to me. Means I can focus on setting my own pace so I get a good idea of what that feels like. And lets me focus on the numbers and my breathing instead of the pain.
I also have SRM units on my bikes. I ride a Neo for Zwift. I have done various analysis and 2 SRM and the Neo are within 2-3 watts of each other. So, when doing normal rides on Zwift I tend to use the SRM as power source and for workouts I love ERG mode, so am more than happy to use Neo as power source. So much so, I have almost finished building a ‘trainer only’ bike for Zwift with a ‘normal’ chainset
YMMV