Does anyone regret getting a single sided power meter vs dual sided?

New year means new pool of money in the bike budget. Last year I spent it on a Kickr Core, this year I’m debating on power meters to train outside with.

Does anyone regret getting a single sided power meter vs dual side? Or vice versa?

With the price drop of single sided power meters from Stages, it would be about ($350 USD) $525 CAD all in for a L-Only Ultegra crank arm vs about $1k all in for the Favero Assioma Duo from their side including taxes and shipping. I can afford both but I fear that if I go with a single sided, I would eventually want dual sided. On the other hand, if I go with the single sided it leaves more room in the budget for other bike related purchases ( Varia radar, new bar + stem etc).

If you were in my scenario, which option would you go with?

I got a stages L side meter last summer and it worked wonderfully for the training and racing I did last summer and fall. No regrets.

6 Likes

Dual sided current Shimano based cranks are known to be off on the right side crank. So you’re probably better off with a left only crank than a dual sided Shimano based crank at the moment. Thanks to @GPLama and others for finding this out and sharing with us.

If you don’t care about 100% accuracy and wanna save money, there’s nothing wrong with a single sided power meter. (Make sure it’s a left crank if shimano based) An improvement on single side means you’ve made improvements overall in performance so it’s something still worth tracking. Just accept that they are not gonna be 100% accurate and for most of us, it will not matter in the big picture.

EDIT: To be clear, they won’t be 100% accurate to your overall power. They can still measure one side perfectly accurate.

3 Likes

I like dual sided power but I would go with the pedals mainly because it’s easier to swap around between bikes and take with you when you travel (I mount my vector 3s on spin bikes all the time - just have to make sure to update the crank length in your head unit).

2 Likes

Absolutely regret buying a single sided. While the power variance is not so bad you can’t train with it I think a lot of problems people run in to is comparing one bike vs another or one bike with a power meter vs a trainer bike with a smart trainer, etc.

I have consistently about a 2.5% lower power output from my left leg so this adds up to a 5% lower number when it is doubled. This can sometimes be even worse when I get tired or I’m doing V02 intervals. The issue that makes it even worse is I have single sided on my gravel and mountain bikes but spider based on a CX bike and I also have a Kickr. With this many power meters I realized what the issue was and it is really annoying to perform testing on a Kickr with a different power meter only to find out your numbers are way off on the gravel bike which is what most of my intervals are on.

My 2 cents from having power meters on my bikes since the days of the hard wired CycleOps rear hubs: The best power meter platform in my opinion is pedal based. They measure a full power picture, they can be swapped between bikes, they don’t lock you in to a certain crankset or chainring combination, and are easily taken when traveling.

I have spent far too much money getting say a Stages left crank arm to match my Dura Ace 9000 crankset, then selling the bike a few years later and getting a bike with SRAM Red. A ton of wasted money doing things like that. I highly recommend if you have a road bike to go with power meter pedals and look for a quality used set and you can use them on all your bikes except mountain. I also expect in the near future we are going to see multiple gravel SPD based options since the patent for SPD cleats just expired at the end of 2019. Once this occurs I will probably swap over to one of those options for my gravel/road bike and keep whatever PM I have on my MTB at the time as I don’t do many intervals on that bike.

Bottom line…go dual and save yourself a bunch of headache.

10 Likes

I’ve been riding single sided Pioneer Ultegra for two years. I don’t regret the purchase in anyway. It has been consistent enough to train very well with. I don’t regret the purchase but I am curious how different a dual sided meter would be.
The single sided pretty much mirrored my KK inride power and if my chain is perfectly clean and my Kickr is having a good day then my power tracks well with it too

I should mention I got my single sided real cheap. Now that dual sided have come down in price it might be worth just going for the dual

1 Like

I’ve said this in multiple places here… I own dual sided Vector 3s, and the only meaningful thing the dual sided power meter has shown me is that I don’t need a dual sided power meter.

20 Likes

Comparing PM data on different PM’s is ALWAYS a problem regardless of dual or single sided don’t you agree?

1 Like

Some great replies above.

I have a single side PM, I would prefer dual sided but can’t justify the outlay, so have to accept that I’m running with a probable 5-10% inaccuracy on my outside power readings due to L/R imbalance.

There is also a variation between my smart trainer power readings and my LHS crank PM so I run with different FTPs for inside and outside workouts to ensure I’m training in the correct zones.

And for me this is the main thing, as long as you have a consistent, repeatable reading to base your training efforts around then you’re fine.

So if you can afford dual sided and feel you’ll regret not having a high level of accuracy, plus added data you get from L/R readings then go for it.

1 Like

haha exactly my experience. I started on a dual sided PM 49-51 on my worst day.
Stuck to single sided since I found out about that. Just hard to generalize our experience for everybody though.

Im running an old quarq one sided and it works fine, and was a great price.

I have a set of Favero Assioma Duos, I felt they were necessary as I’m coming off a knee surgery on my left and knew my leg side power would be lower than my right. Its about 45/55 balance for me.

1 Like

Not all all. 4iiii left crank has been great.

4 Likes

Nope. Single sided have been great, both 4iiii and Stages gen 3 for me. And full disclosure, I have a slight imbalance from an old injury.

I’ll assume anyone hand wringing over L-R imbalance is typing on this forum while doing one legged squats and calf raises… :wink:

1 Like

If you have ultegra gearing as i have on my Madone do i need to get an ultegra PM or will 105 do the job. New to PM’s. Thanks.

Nope

Any hollowtech 2 crank will fit, you can stick 105, dura ace,XT or whatever on

You just need to make sure you have chainstay clearance

Single sided Favero pedals. Love them.

2 Likes

I started with a single sided power meter (Stages), but replaced it with dual sided Vectors. Now I can’t compare the two sets of data, as it turns out that my L/R balance is usually around 52-53%.

Yes’ish :wink: I’ve seen 25 watt differences due to single side only problems. I don’t necessarily agree that all PMs need to be of the same brand and same location on bike as there is enough tests out there by Gplama and others that show them tracking very closely. There may be a few watts here and there but comparing any single vs a full measurement of both sides is an exercise in futility.

Every time I read a thread post of someone saying their PM doesn’t track with their smart trainer I just roll my eyes when I see they have a single sided PM. There is no point in even asking the question if your PM is guesstimating you’re right side power. It is more luck than anything if they actually track well vs being accurate to each other.