On Topic-Single-Sided vs Dual-Sided Powermeter

[IJWS]

Paceliners,

TL;DR - I need a powermeter. Can I get away with a single-sided pm for a few months?

Background:

I am recovering from a broken leg. I've been riding indoors with Trainerroad since February and it has been pretty helpful. It gave me a lot of time to work on my fit and technique. Last week was a recovery week and I did almost all my rides outside. Wow. I like that better. I want to keep doing the Trainerroad program I'm following but I need a powermeter on my bike to do so.

For a while I was sure that I would order a pair of Favero Assioma powermeter pedals. They are inexpensive, review well, and I can move them from bike to bike. But Covid-19 has some weird side-effects. Favero Assioma is in Italy and not shipping right now and getting a more complicated pm like crank-based installed comes with a long wait time because the whole world is remembering that bikes are fun (good problem). There are a few pairs of their dual-sided pedals online for $200 over retail (+tax and shipping) and I found one pair of the single-sided pedals for a reasonable price (you can add another pedal later to make them double-sided) but the single-sided pm is on my left (broken) leg. There is definitely a discrepancy between the two legs--I constantly focus on my left leg but my right leg takes over for big efforts. I thought it would be fine if the pm was reading my strong leg but I am wondering if having a pm on my weak leg is a bad thing...or a good thing.

What does the Paceline collective think?

[AngryScientist]

i think a few of the dual side meters allow you to see the discrepancy between the two sides right? i think that might be useful and interesting information, considering the recovery from broken leg. you could probably watch your leg strengthening over time.

i think for that reason alone i would go dual if i were in your situation.

[Coffee Rider]

I have the Favero's and really like them. It's been surprising to see a discrepancy between my legs. I'm right handed, but I'm putting out more on my left side. Based on their current unavailability at the RRP, I'd suggest also taking a look at the Powertap pedals and the Garmin Vectors. I've heard that the newer Garmins don't have the dropout issues that the earlier ones have.

[Andy sti]

Is a double sided or spider based meter better - sure, but it really wont matter. For doing your workouts outside a single sided meter will work just fine. Don't over think this. A stages, 4iii, or single pedal meter will give you the data you need to complete your training and improve. Remember that training zones are zones, i.e ranges. If you're reading from your slightly weaker side you are still going to get to the appropriate zone. I wouldn't worry about it.

[madsciencenow]

I’m with Andy unless you really care about seeing the differences now. In addition, if you see there’s a difference what are you going to do about it? If you have a strength plan or something maybe it matters but otherwise it wouldn’t be a big deal to me. I started out with a quarq for my first PM and it read both legs. It was fun to see all the data and the slight imbalance (it can also change over the course of a ride as you fatigue) but ultimately one leg is enough for my needs and I’ve been on stages single-sided ever since.


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[glepore]

Is a double sided or spider based meter better - sure, but it really wont matter. For doing your workouts outside a single sided meter will work just fine. Don't over think this. A stages, 4iii, or single pedal meter will give you the data you need to complete your training and improve. Remember that training zones are zones, i.e ranges. If you're reading from your slightly weaker side you are still going to get to the appropriate zone. I wouldn't worry about it.

I've had powermeters for 20 years, starting with srms. Have had pretty much every iteration other than pedal based, and have serviced thosse. Fact is that there is nothing really you can do about an inbalance. If the powermeter is precise, it really doesn't matter how accurate the number is SO LONG AS you test and train consistently with the same device. Whether its single sided has little to do with this. Your measuring output as a physiological marker and setting zones.
Another thing-unless the pm has separate strain gauges on each arm, its just estimating r/l balance. Every single sided crank based pm (ie srm, quarq p2m and others) is doing this. The secret sauce is pretty good, but its not actual l/r balance.
So use whatever device you want. Keep in mind that they all have their quirks, but for most folks not doing micro sprint intervals to a number (ha-most real sprint intervals are "go as hard as you can, recover, repeat) then most all are passably good. Some are a bit laggy for short interval work, but for non professionals almost certainly ok.

[teleguy57]

I have the Assioma Duos because I knew one of my legs wasn't as strong as the other. I can be more consistently balanced when I focus on it.

I'm likely headed to knee replacement this fall, and believe that the Duos will help me as I get into rehab and targeted even higher levels of fitness.

[purplecu22]

to add to this post a question.

So i have a shimano crank, all the way back to 10 speed, it has the hollow tech II spindle. Plus i have newer shimano cranks 10-11 speeds. So any shimano hollow tech II crank arm will fit.

If i buy a single sided power crank arm, i can run it on a 10 speed crank, 7000,8000,9000, and 9100 crank set. I know its a miss match of crank but it only reads power on the left side. Then doubles it.

How off would it be really. I would like to switch the power crank arm between different bikes.

Anyone do this

[shrimp123]

How off would it be really. I would like to switch the power crank arm between different bikes.

Anyone do this

(outdoor rides only) i had a 6800 crankset, but, got a deal on a 8000 left-stages. Used it for about 3-4months. Then, i got a 8000 crankset as a gift and moved over. The readings were very close. on a sample of 1, it is "identical". now, note that i only push ~200W and i dont care if my ride says 190W. So, when i say close, i mean less than 10% difference.

sidenote : if you plan to swap between bikes, a hub based may be attractive (powertap). It is far easier to move a wheel than a crank arm.

[superbowlpats]

Is a double sided or spider based meter better - sure, but it really wont matter. For doing your workouts outside a single sided meter will work just fine. Don't over think this. A stages, 4iii, or single pedal meter will give you the data you need to complete your training and improve. Remember that training zones are zones, i.e ranges. If you're reading from your slightly weaker side you are still going to get to the appropriate zone. I wouldn't worry about it.

this x100

I have a Powertap, Quarq, and a Power2Max on various bikes. If i were to do it over again I'd go with a pedal.

[R3awak3n]

I agree that although is nice to have dual sided power its not necessary for most. As long as you see the number improve then you are doing the right thing. I had 2 p2ms and a powertap. Also have had a quarq. I just sold 1 of the p2ms and in the process of getting rid of the powertap. I am going pedal so I can just have 1 PM for a few bikes. Will keep the p2m because its on the gravel bike and I don't want to ride road pedals on that bike.

Was looking at Favero but sold out everywhere, also interested in the powertap pedals, they are a bit heavier and stack height is a bit higher but my powertap has been excellent so I know those pedals will too. I do like power2max, I love that it also calibrates so you don't have to do that all the time.

Oh, I would do dual for the right price but for my amateur-ness, single side is more than enough.

[NHAero]

Are all the pedal-based products only road pedals?

[R3awak3n]

Are all the pedal-based products only road pedals?

not anymore. SRM just (or is about to) release a SPD power meter.

You can also modify the favero assioma to work with an SPD pedal (will void warranty and in some cases have to cut a chunck of the shoe sole).

I think, with the booming of gravel, more companies will make SPD pedal power meters. I just don't want to ride SPDs on my road bike or I would just get the SPD SRM and move it btw all bikes but I still like a good old road pedal/shoe combo

[Andy sti]

Are all the pedal-based products only road pedals?

Yes and no. SRM has a set of off road pedals but I’m not sure if they are fully released yet, plus they are ridiculously expensive. There is a hack with Xpedo MTB pedals and the Favero but it’s not an official offering. GPlama did a video on it and there are threads on Trainer Road and WW about it.

[NHAero]

Thanks gents.
I have nerve damage from a herniated disk leading to muscle loss in lower left leg, so I'm interested now that I'm riding more what the left-right balance is, and if there are ways to make it better. Also, for the past 7 months I've had a brace that prevents ankle collapse, enabling me to stand on the pedals and push harder, and I'm curious about the difference with and without the brace. So I'd need true left-right independence to learn something useful.
I have Eggbeaters on five bikes, and no road pedals or shoes - never had them. I suppose that could change if needs be. I also have a pair of custom Luck shoes where the left one is 1/2 Euro size larger which accommodates the footbed piece of the brace nicely (thank you so much Doomridesout). So investment would be more than the pedals. But pedals seem like a good approach so i could swap bike to bike.

[mcfarton]

Not all of the power meter pedals swap easily. A power tap wheel swaps easy if your bikes all have the same number of speeds.

I have a staged single side power meter. It’s the only one I have ever had. I have been very happy with it. It had a problem and stages fixed it no cost to me. I have two bikes that don’t have a power meter on them. I have thought about getting pedals or something so that I could have power on them. In the end it doesn’t matter and I still enjoy riding them without a power meter. Not every ride has to be a workout/race


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[Coffee Rider]

It appears Blacksmith Cycle has the Faveros in now.


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[R3awak3n]

It appears Blacksmith Cycle has the Faveros in now.


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link?

[grilledcheese]

Single sided is completely fine. I've had bad luck with pedals, but never had trouble in 5 years of power2max and recently Stages.

[Coffee Rider]

link?

It was just posted on the Instagram page. It doesn't look like the website has been updated yet.

[IJWS]

Well, I think I will go with single-sided if I can ever find a pair for sale. Everywhere and everything (hyperbole) seems to be sold out.