I’m buying new crank arms for my gravel bike, which I only use for “solo rides” and endurance rides. I use my road bike for fun riding and training and it has a power meter. I use my Kickr for indoor training.
Do I need to buy a power meter for my gravel bike to have TR register my gravel solo rides and endurance rides correctly? I always wear a HRM
I’d be interested to hear Eddie’s opinion on this from the TrainerRoad AI feeding perspective.
For non-TR related reasons you could argue it’s in your interests not to buy a PM for your gravel bike. These include saving money, learning to ride by RPE and managing your fatigue by paying attention to your body. Also just enjoying outdoor riding without worrying about data.
I’ve been through the exact same scenario with my XC mountain bike, so far I’ve resisted the temptation to put a PM on it (my road bike has one too) and I’m having a great year so far.
Edit: I’ll caveat that by saying I self-select all workouts so I can’t answer your actual quesion!
I do all that with a PM. For non-workout rides, I don’t pay attention to power. I do like having the data post ride, and of course having it upload to TR. Historically, power is all TR used and it didn’t use HR. Using HR data is a new thing and I don’t know how it’s factored in.
It’s certainly possible to create a profile on the head unit that doesn’t display power. The way I see it, the only reason not to have a PM is cost.
That’s fair, I can’t say I’m not tempted.
For the OP would supplying TR with power data for outdoor endurance/unstructured rides meaningfully change how it suggests workouts?
I definitely think so. On my last plan I wound up doing a lot of unstructured rides instead of the plan’s workouts and the plan adapted and predictions changed appropriately. I don’t know how it could do that without power data.
Depends on how well you recover from these endurance rides.
If you have good durability and can recover from a 4-6 hour ride in 1-2 days, then I’d say no, because TR will use your data against you: assume you’re cooked, then alter your next week’s workouts and make them all easy.
To be honest I don’t understand why someone would not get a powermeter with how affordable they are these days. $4-10k bikes, a pm is a drop in the bucket to at minimum just log data, and the upside to use it during rides if you choose.
I would hope TR is making the correct decisions based on my activities for achieving my goal. If TR has me back off after a hard week, then I expect that’s the right thing to do. It’d be the same with a live coach. Of course if I thought I knew better than the TR, or a coach, maybe I might try to game them, but then what would be the point of paying them in the first place?
A better way of asking my question is if having only heart rate data and no power data for “solo rides” and outdoor endurance detrimental for using the trainer road system.
Because TR’s forte is analyzing its own structured workouts, not unstructured outdoor rides.
Yes. That was definitely the way it was. Before AI, it basically didn’t utilized unstructured rides at all. Then there’s been a “transition” period with AI that had its ups and downs with many things including analyzing and utilizing unstructured rides. Like I said earlier, on my last plan I wound up doing mainly unstructured rides instead of the plan’s workouts and the plan adapted and predictions updated appropriately.
If you’re taking your training seriously, you should get power. If you’re attempting to be economical, find a set of single-sided Gen 1 Favero Assioma pedals. I see them on eBay for $300-ish. This will let you move to new bikes with you while giving you dependable, accurate data. https://l1nk.dev/yng6azy
Personally, my avg L/R balance varies quite a bit from ride to ride. Sometimes it’s close, like 52/48 and sometimes it’s more like 57/43 as measured by Assioma Duos and spider PMs (which estimate L/R power). That would report an avg power of 4% higher than actual in the first case and 14% higher in the second. IMO, that’d enough to be consequential, so I advocate for dual sided or total power. Power Meter City is a good site to see what’s available, prices, and for related tech info. I’ve bought a couple of PMs from them.
Out of curiosity, what have you done about your imbalance?
Nothing. I could pray to the powers that be to please make my two legs the same, but I’d probably wind up with two weak legs. (to paraphrase an very old kid’s joke)
I also advocate for dual sided but single sided is better than nothing. Generally my athletes if they are lopsided are always lopsided within 1-2%. I’d look into it if you are significantly changing balance ride over ride.
Hey @jdm 
Great question! It’s worth breaking it down a little because there are actually two different systems at play here.
AI FTP Detection reads your power data to estimate your FTP, so the more rides you have with power, the more complete the picture it has to work with. Think of it like a coach watching your training. The more they can see, the better they can assess your fitness.
Then there is Fatigue Detection. It does work with HR-based TSS, so your gravel rides aren’t off the radar for load and recovery purposes.
If your gravel rides are mostly easy endurance on top of your structured indoor training, your indoor workouts are doing most of the heavy lifting in terms of training impact. But if those outdoor rides are a big part of your overall training, or you’re pushing hard on them, a power meter would give the system a much fuller picture of your fitness.