If your unit of measure changes, you always should retest. People obsess with numbers here, but we’re all measuring with different rulers.
You wouldn’t build a house with mm and then switch to inches, and keep the same values? That’s how NASA crashed a rover into the moon… Or take a baking recipe that requires 450g of flour and change it to 450 ounces…
I have assiomas for outside but don’t bother to use them on the trainer. My numbers are very different inside and outside but I don’t mind so much, I just do my structured rides inside and those numbers are based on ramp test on the trainer, and outside I either do long z2 rides or I go out to have fun crushing myself. I’ve mentally adjusted for the differences and intervals.icu seems to be able to account for inside vs outside ftp.
This way I can have a permanent trainer setup and outside bike without having to swap pedals or anything.
My Stages didn’t agree with my Tacx and it was off by a mile. What I’d recommend is doing a comparison where you record both trainer and Stages simultaneously. At least then you’ll know how they compare.
I was a long time stages user and used it with power match vs my elite direto.
my 2 cents.
try to stick with 1 source of power, inside or outside, that way TSS/power pbs etc. are all taken from a single source, I think based on forum experience its quite common for trainers and power meters to have some discrepancies.
After using a stages left only and then switching to a quarq, I had a 20w drop off due to the left/right imbalances unique to me. It’s not a bad result, but it takes a while for your brain to recalibrate to seeing a lower number etc. The good thing from my stages was that it was consistent to itself which is all you really need.
If I were to do it all again, spend a tiny bit more and get a dual sided/total sided power meter. luckily now assiomas/quarqs are not that much more vs a stages. It’s a long term investment and you’ll use it almost daily, so just go for the best!
I have a similar setup to you, except that I had my Stages PM first, then bought a smart trainer (a Kickr) later. So for me, the obvious thing to do was to just use powermatch in TR, with Trainerroad then taking the power from the Stages.
I think it’s probably easier to do it that way for you too, to use the same power source (the Stages) for both indoor and outdoor rides, instead of adjusting FTP each time. As your FTP is based on the Kickr though, based on my own experience, I think it would be worth re-doing an FTP test or doing a check to see how your Stages and the Kickr compare.
I did this recently, when I bought another Stages PM for one of my other bikes. My Kickr was controlled by TrainerRoad in ERG mode using Bluetooth. My Stages was connected to my Garmin via Ant+, so I could collect data from both power sources independently. I collected averaged power data at several stabilised powers to compare my three Stages PMs and the Kickr. The results below show that the differences versus the Kickr are up to about 20W, so not massive, but significant enough to need some adjustment or some consideration.
It’s better to think of you not giving up and just measuring with a different ruler.
You you really have to take other’s watts / ftp with a grain of salt. Some people with 300w ftp might be really at 270w or 330w, if tested on calibrated equipment in a lab. For a 65kg rider, that’s either 4.1w/kg or 5w/kg, and everywhere in between.
FWIW, I do not use PowerMatch but that’s only because my PM and trainer are usually within 1% of each other. If they were further apart I would bother but, since they’re not, I keep them separate so I can cross-check them against each other to detect any abnormalities. Not everyone’s equipment is that close, though, so I would try a few rides with them apart to see how close or not they are before deciding. If you choose to use PowerMatch (or any time you change how you’re measuring power), retest or otherwise adjust your FTP accordingly.
I’m overly analytical but also like riding by feel. My current best approach to making inside and outside virtually the same:
disable smoothing in Wahoo app
connect to Kickr (wheel-off) via Bluetooth
in TR app switch to Standard (TR terminology / Level (Wahoo term) mode and set level = 1 or 2 or 3. For example I’m using 2 with an FTP of ~250W
load workout on Garmin and perform workout just like you are outside. For example riding at 70% FTP and then grab two gears and do sweet spot intervals with bursts (Ebbetts). Without shifting in level = 2 I’m hitting 400% FTP 5-sec sprints
You may prefer the TR app’s blue bars and display, I like the TR app too. In that case turn on PowerMatch and use Erg.
Not sure what happens in TR app if PowerMatch is enabled and you switch trainer from Erg to Standard, believe it will record power from Stages but I haven’t tried it recently.
I don’t use power match either. It was awhile since I tried it and I should try powermatch 2.0
When it comes out, but just felt the erg mode was smoother from the trainer. That and the power was pretty close.