The need for a powermeter when you have a smart trainer

Given that a smart trainer (a Wahoo Kickr core in my case) provides a power measurement, what is in your opinion the added value/benefit of also having a powermeter in addition?

There are the obvious differences, such as the fact you can actually use a pm on the road, and therefore you can train (with power) when on a ride instead of just on the trainer. However, as I’ve personally never had power on a road ride, I’m interested in your opinion and experiences of having both a pm and a smart trainer and whether the former adds any real value.

Thanks, cheers!

Well you hit on the obvious answer….you can train / race with power outside. Now if you are not interested in training in a structured manner outside, then the value of a separate PM diminishes and it basically just becomes a data collector. However, if you are tracking your TSS / CTL then that data is still valuable.

If you are just interested in riding outside (group rides, solo, etc) and don’t track your training data, then there isn’t a lot of value in a separate PM.


I got a power meter after years of training on a smart trainer. I have to admit, it hasn’t changed my life. I only do structured training inside (I don’t love the idea of staring at my head unit on the road, Froome-style). On the road, I’d say it helps me a bit pace myself up climbs (start climb strong, look down at wattage, say, nope, I’m not keeping that up for 10 minutes). Also, power on the road doesn’t feel the same as power inside, so it’s neat having a tool that equates them. And it’s kinda interesting for post-ride analysis, but again, not life changing. Heart rate is more interesting for me to look at post-ride.

I’d say for me, it’s neat, but there are probably other things I could have spent the money on that would have improved my experience more.


It’s consistency. There can be a 10/15w difference between my Elite and my Faveros. It’s not about one being ‘right’, it’s about comparing like with like.

I learned this the hard way 2 years ago after an FTP test on the Elite. The next few outdoor interval sessions (using Faveros) were beyond savage :rofl:


I did things similarly to the OP, got a smart trainer and then added the PM a year or so later. For day-to-day riding, it doesn’t make a big difference for mevbut when I have travelled out to longer/steeper terrain (it is fairly flat where I live) it’s really helped with pacing and understanding the effects of travel fatigue, altitude, etc.

This is where TrainerRoad has an advantage with their PowerMatch feature…it ensures the power on the trainer matches the power from the PM. As a result, efforts feel relatively the sme between outside and inside.

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Don’t all the software packages offer this in some way? I know PerfPro and I believe Rouvy allow you to control the trainer with the PM.

Many do, but one that lacks it is the Wahoo Systm (Sufferfest of old). There may be other more fringe ones that also lack it.

I don’t know…I really only use TR and I actually don’t even use PowerMatch. I Zwift occasionally as well, but just let the trainer do its thing. My trainer bike doesn’t have a PM

As others have mentioned, it’s nice to have power outside but not mandatory. I don’t do intervals outdoors, buts it’s still pretty cool to see I hit a new power PR on a challenging group ride. The other advantage is software like Garmin Connect or Golden Cheetah can better estimate your training load with good power data, so it’s helpful even if your not doing structured workouts. I have power on my road bike but decided it was unnecessary for my gravel bike.

One other thing, it is helpful in identifying power differences between your legs if you get independent LR pm pedals. I noticed my individual leg output differential was widening over time and it prompted me to make fit adjustments.


Curious- what did you change?

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My average left right power drifted from 50/50 to 48/52, over two months

Sorry, I meant, what did you change about your fit or riding in response?

Lowered my saddle and moved it back, moved my cleats back towards my heels, got narrower handlebars, added 1 cm of spacers, and shortened my stem. I also bought some podiatrists felt and put some underneath the insole to help stop pronating on one side. I may try using an angle wedge too.

I am also strengthening my glutes with kettlebells swings and single leg deadlifts.

Had the help of a bike fitter and then a physio through this.

I felt some improvement but illness and work have kept me from consistent training since I made these changes. So not sure if it fixed anything yet.


I have a PM on one of my bikes, and access to a smart trainer. I found that I prefer outdoor workouts, which I mostly have done up hill staring down at the Garmin Froome style. In my case I sometimes struggle to motivate myself to train so excuses like the faff of the trainer bike not fitting me well, or the need to change the cassette if I want to put my bike on the trainer to use almost stop me training. As others have, when you’re not training all a PM is doing is data collection. I still occasionally do intervals indoors as all you have to do is pedal though,

if you race, having a PM is useful in races, sometimes. for many races, it’s useless - you just do what you can. for others, e.g. longer road races, time trials, it can be useful to gauge your effort with a PM.


This is really interesting to me… I wouldn’t have reacted at all to a variation that small, as it seems small enough to be a statistical error. If it were consistently 40/60 I might think differently.

I’m not sure balancing L/R power for balance sake is a goal worth pursuing. I’d also be concerned that by “fixing” the balance, all I did was reduce my power overall. Just random thoughts.

FWIW, I do look at L/R power balance after my rides but I’ve found that at least for me, it seems to vary from day-to-day… one day the left is marginally stronger, the next the right. Somedays it’s perfect. Thank god I don’t use this measure as data on my head unit… that would really drive me crazy.

But you gotta do you!

Yes I gotta do me…. the main thing is I had very consistent 50/50 balance which went to 51/49 after a few weeks and the 52/48 a few weeks after that. I felt a difference in my riding as well, and felt that the gap would grow if I didn’t make adjustments.

Others may have shorter term fluctuations or simply feel ok and not take action, and that is fine.