Doomrider74

Preferably one that can be upgraded to dual-sided in the future. I don't need to transfer it between bikes so I'm thinking a crank arm.

Bike is a Specialized Tarmac SL6 with 105 groupo.

terrymorse 

I recently bought and installed the Favero Assioma UNO pedals (UNO = single-sided).

Very easy to install and set up, and they are working flawlessly. Look keo compatible cleats.

https://cycling.favero.com/

Doomrider74

Thanks, but I should add I use shimano road cleats.

rivers

I would second the assioma pedals. They're brilliant. I switched over from Shimano pedals and have no issues. I swap the pedals between my road and TT bikes with lout issue. Takes about 2 minutes.
I think the Garmin Rally come in SPD-SL, but they're not cheap.
if you really don't want to swap your pedals out, 4iiii single sided is an option, but to upgrade to dual sided might be more expensive.

terrymorse 

Then you’re probably stuck with the Garmin Rally. More expensive, not rechargeable.

https://www.dcrainmaker.com/2021/03/...-look-keo.html

Doomrider74

Only if I go with a pedal-based system.

PeteHski

I have a Specialized Power Crank (Shimano 105 version) on my endurance bike. The sensor is actually made by 4iiii, but has better weather proofing. It’s been faultless for over a year and very consistent. It was also a very good price on sale when I bought it.

Dean V

Do you have a problem with Look Keo that you don't want to use them?

CadenceCrazy

I have a single sided 4iiii that works well so far but I've only had it for about two months. Installation was painless and it syncs immediately with my Garmin.

Doomrider74

Yes: I have shimano pedals on my gravel/Zwift bike as well, and use the same shoes. I don't want to have to get another pair of shoes.

Mojo31

The Stages 105 arm (latest version) has worked well for me on my Domane.

RChung

With the 105 group, I wouldn't bother going to a dual-sided in the future. There are known issues with instrumenting the right side crank arm for that design. If you're set on a left-side crank arm, you should probably consider that a non-upgradeable purchase. Which is fine, if that's what you want and it meets your needs.

Doomrider74

Thanks for the info. Could I get an Ultegra left PM crank arm, then? I'd then upgrade the right to Ultegra later.

Iride01 

4iiii let's you get one sided now and move to two sided later. I think stages does too. I'm still waiting for 4iiii to get my cranks in stock so all I have to do is swap. I used to want PM pedals but crank based is so much cheaper currently.

Doomrider74

Looking at a local store, I can only get Stages at the moment. Apparently, 4iiii are having problems sourcing cranks/arms.

RChung

The issue is with the asymmetrical 4-arm right side cranks, so that means Shimano's current 105, Ultegra, and DuraAce cranks. It doesn't apply to the older 5-arm cranks.

Doomrider74

Oh, noted. Thanks. Would you suggest pedals are a better option then, if future upgrading to dual-sided is considered? Or just not bother with upgrading to dual?

RChung

It really depends on what you hope to do with the data. For many purposes, single-sided is fine; for a few, it isn't. I happen to do some of those things, so I need as much accuracy (not just consistency) as I can get -- but I'm in a minority and many many riders are perfectly fine not doing those things.

That said, we can't always know what we might be interested in doing a few years from now. Sounds like you have good reasons not to go with pedals. *if* you think you might need total power in the future, you might want to consider a crank spider PM, like the Power2Max or Quarq or SRM. I often recommend the used market for someone first starting out so they can get in at a lower price point and figure out what they'd do with the data. I just bought a spare Power Tap hub that was being sold by someone who was switching to (dual-sided) pedals: I paid $125. Power Tap hubs have been discontinued so as used power meters they're really kind of a bargain.

Doomrider74

Thanks. In 35 years of cycling I'd never used a pm until I bought a Wahoo Kickr in the winter and started using Zwift. Since then, I've noticed I have a tendency to "tap" whilst out riding on the road, and I want a power meter to have some kind of reference (I'm not expecting to number match with the Kickr). Obviously, this isn't a particularly scientific use of a pm, which is why I think a single-sided would be fine for my CURRENT, purposes. However, as you say, I have no idea what I may want from the data in the future, which is why I was looking at something upgradeable.

Maybe I'll stick to single-sided as a starting point and see where I go with it.

I'll have a look around for second hand stuff as well.

PeteHski

I think a single sided crank power meter is fine for most people and obviously a lot cheaper. Pedal based systems seem to be more hit or miss in both reliability and consistency, but handy for swapping between bikes.

RChung

If you have the same BB on different bikes (not everyone does), swapping crank spiders can be faster than swapping pedals.

asgelle

So not this one? https://www.google.com/shopping/prod...bTnBhEQ9pwGCAc

RChung

Well, it makes me feel even better about my purchase. It wasn't just a bare hub but came in a wheel, and I did a static torque check to validate that it's working properly. I still use rim brakes and lots of bikes are going to discs, so that's another reason why you can find bargains in used Power Taps if you're not in a hurry.

asgelle

I've been accumulating them as well. I'm almost embarrassed to say I enough to have one dedicated to each bike I ride with two left over that I've lent to people curious about riding with power.

I might add for people worried about longevity and serviceability I occasionally ride hubs from the wired and 2.4khz era that still work fine and pass a static calibration test.

guachi

I have a 4iiii 105 single-sided. It basically just worked. Though if you can get a Stages then that should work well, too. I'm not sure I've read of anyone having any problems with one. A pm was one of the best things I got for my bike. Allows for some consistency between indoor and outdoor riding.