Outdoor training without a PM

I’ve both googled this and looked on this forum… I’ve just started with SUF and my plan has outdoor riding at the weekends. This I like a lot as it fits my schedule and preferences (quick turbo sessions during the week and longer real rides at the weekend).
However, I’m not really sure how I would complete these rides as a true workout as I don’t have a power meter on my bike, only on the trainer.
Am I missing something obvious?


RPE would be the obvious answer. This takes practise, in my opinion.

When I ride outside it is always a longer ride at an easier pace. I always record my HR and speed/cadence/power when outside but only for analysis afterwards - very rarely do I look at the numbers when I’m outside.

It’s always worth bringing yourself back to the enjoyment of simply riding simply.


That was kind of my plan to be honest in the absence of a concrete option. Ride for the prescribed time, but just ride… Indoors is better suited for staring at numbers.


I think the outdoor workout have descriptions for the sessions, which includes RPE?


Outdoor workouts also include recommended heart rate zones in their description, so you can also use that and/or RPE if you have a heart rate monitor.

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And honestly, depending on the cranks you have a left sided crank arm PM isn’t that pricey, especially used.

When I’m doing things indoors, I let the program (zwift/sufferfest/etc) control my erg, but I record power using the crank based PM. That way my indoor and outdoor power are consistent.

It’s not necessary as others have pointed out, but it’s certainly helpful.


For me, it is like not buying a smart trainer. I can’t justify paying for something that is almost equivalent to almost one month’s mortgage.

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Don’t worry - in the good old days, everything was RPE. The fact that smart trainers and bike PM’s have become cheaper, doesn’t mean everybody can afford one.


I hate RPE and really have no perceived idea. It varies from time to time

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As does anything else…

I paid like 200 bucks for a used left sided crank PM.
If that’s a month of your mortgage, I want to know where you live so I can buy a house lol.

Seriously though, I remember looking at powertaps and SRM’s in college when I was lucky enough to get ‘gifted’ an old wired SRM. Zero chance I would have been able to afford one but oh my gawd did it make my on the road training better.

If you’re semi serious about stuff, keep an eye out for deals on used left sided crank PM’s. Like Cyclopaat pointed out, it’s not a necessity, but what can I say… I’m a data nerd.

That is helpful. Thank you! Now I’ll know what to keep an eye out for. Last time I checked, used ones were between 6 and 800 bucks. My monthly mortgage is just a bit more than that.

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You can get a new stages or 4iiii for like 300 bucks now. I’ve seen used quarq’s go for 500-600. This is for the shimano and FSA units. If you’re running some of the cannondale SI cranks the prices tend to be a bit higher since there’s more demand since those bikes tend to attract racers. Just checked ebay and looks like sold items show a few shimano ones in the 200-250 range used so looks like it’s still happening.

One sided power meters definitely have their short comings, as folks like to point out that you just double the power that one leg is putting out. But at the end of the day, if you’re improving, you’re improving. Unless you have some biomechanical weirdness or injury at play, you’re probably going to be strengthening both your legs at about an equivalent amount.

And if you have a smart trainer, you can use the trainer to control the erg setting and get power from the PM and see if there’s a difference there.

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Self own.

Had a terrible experience the other day and felt like poop when I realized that my crank based pm and kickr weren’t agreeing on numbers. Looks like I didn’t follow my own advice. The next time I test, I’m likely going to record everything on the trainer and just datalog on my PM. That way I’ll have the Kickr’s numbers for Sufferfest workouts which will be internally consistent, and I can datalog everything on the PM so I can keep inside and outside numbers the same.


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Just an FYI: probikekit is having a sale on the 4iiii R7000 left sided crank arm right now. Was about 265 shipped for a new one.

I just got my ultegra left side crank 10% off with code VCUK10 max £25

There are cheaper power meters then the traditionally ones. I myself have bought the powerpod (https://velocomp.com/powerpod/) and I’m satisfied with it. Even it still cost a lot, is much cheaper then the other types.

I got a good deal on a Specialized Power Crank (Shimano 105 version for £265 in UK). My quality of training has improved no end since I’ve been riding to power. Numbers correlate very well with my Elite smart trainer too and I have more confidence in my numbers with 2 independent power sources.

If I was forced to ride outdoors without power I would at the very least wear an HRM. I find RPE just too subjective once you get into more structured training. But riding without any data is still valid, just less controlled and much harder to judge your efforts from one day to the next.

Unfortunately those are of very limited utility.

See DCR for reference.

I don’t have a power meter. I record my outside rides with a Wahoo Bolt and runs with a Suunto Spartan. I have a HR strap and a cadence sensor on my bike shoe. If you want estimated power there are some apps like Strava that will do that too. DC Rainmaker has commented that the Strava estimates are not all that bad. An outside MTB or road ride is the reason I am doing this sport in the 1st place and so focus on the ride and any coach instructions and the rest is just enjoying the outdoors.