Q4 2021 double sided Power meter recommendations for 9100

g’day all, I’m considering upgrading the road bike with power meters… I’m running DuraAce 9100, so whatever I do will need to fit with that… I’ve had a read through previous posts on power meters, and whilst popular, it looks like the Assioma don’t support 9100 with their DUO-shi model? (I’ve emailed them to confirm).

4iii looks like I need to actually replace a whole bunch of otherwise-working-just-fine-components… and tbh I’d need help to replace my cranks, which adds to the cost.

Garmin Vector - I’ve got a Wahoo Bolt Head unit - will it play nice with this and give me double sided power? I’m also not keen because I think it changes the height of the pedals, which will impact fit.

Quarq - looks like they do have a 9100 option… but no stock anywhere

and of course Shimano now have a 9100-P option. that also involves replacing a bunch of otherwise working components, and otherwise similar installation issues to the 4iii.

AFAICT Wahoo don’t have a power meter option. I’ve been really happy with their support of other products, so if they had one I’d def consider it.

I’m not going to mix & match indoor / outdoor. I’ll just use the power readings from the trainer for indoor, and if there’s a consistent variance to outdoor - just work out what the variance is and take note. If the variance is inconsistent… well… that’s a different issue :slight_smile:

Any thoughts?

Hi Sir @pb07

Not an expert on this but been researching for my older bike so herewith my thoughts:

Easiest - pedals with Favero Assioma being the ones to go for if you have the cash. By saying the FA DUO-Shi are not compatible with 9100 I take it you have Dura Ace pedals? If so, you could sell the pedals and put them on Ultegra pedal bodies (not a huge change from the DAs) or save a few more quid and put them on 105s (still excellent pedals). No changing cranks/ BB/ chainrings etc. Moveable between bikes. Excellent.
Garmin Vectors you’ve mentioned.

Cheapest - left side crank only (Gen 3 Stages or 4iiii) - swapping only one part out and unless your trainer shows a marked discrepancy between your L and R single-sided is fine for most.

Quarq - make for 9100 but it means swapping out cranks and BB as well as installing the power meter. So quite a bit of swapping out and cost of installation. From what I’ve read excellent though.

Shimano - you’ve mentioned all the swapping out required. Not the BB though.

FWIW I run DA 9170 with the Shimano dual-sided crank-based PM and am very happy with my setup. If I were in the market though and money was not a prohibiting factor I would go for the FA DUO-Shi pedals with Ultegra bodies - accurate/ reliable/ easily moveable.

Hope that helps.


Hi Sir @Craig.Quarmby ! Yes, I’ve got the DA 9100, so was hoping to stay “in the family”. I wonder how the actual Assioma pedals compare with DA / Ultegra etc (i think they have their own branded SPD compatible full-pedal option). And… curious if you need anything funky to get useful doublesided data out of them via Wahoo Bolt, or does it just auto-magically just work? Wahoo integration stuff seems a bit behind Garmin. It appears Garmin put more effort into doing new integrations (for example the light controls - although from what I’ve heard, that’s a bit flaky), and the bloody sugar monitors (non-UCI approved and all…). I’d like to see Wahoo put more into this area.

The standard FAs have Look compatible cleats and if you’re in a situation where you can change from Shimano cleats to Look style you’d probably get used to the new setup pretty quickly. Not sure on stack height differences so may be some adjustment - somebody that has them may be able to chime in.

If you wanted to stay close to the ‘family’ with the FAs then it would be Ultegra bodies as your highest rung at this stage. I’ve been running the older Ultegra pedals (6800) for years now and they’ve never missed a beat.

As to integration with Wahoo - I run Garmin Edge as my head unit so can’t comment further.

Sorry, end of my limited knowledge.

Now for comments from those who have what you’re looking at …

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Great comments from everyone but just wanted to add that swapping components can actually lower your cost a bit if you are willing to sell your existing parts. Not sure what a 9100 crankset is going for these days, or the whole groupset if you go di2.

Good luck with your research!

I’ve used an iBike Newton, then Stages Single and am now using Vector 3 Dual. They have all been consistent but the Vectors the most accurate. The upgrade path was costly because people typically won’t buy the iBike and I needed my crank arm.

I went from R8000 Ultegra to the Assioma Duo pedals and I can’t remember noticing any difference or niggles from the change. I would expect there was some difference in Q factor / stack / etc but I couldn’t tell. The Look compatible cleats that came with the pedals have been fine - potential small extra cost to factor in if you’ve multiple pairs of shoes to change the cleats on.

My very old Edge 800 does show L/R balance but doesn’t have the fancy Garmin Pedalling Dynamics support like the newer models (though the Assiomas don’t send all the PD information):

Does budget influence your choice? In the UK, the Assioma Duo are about £595 (the Duo-Shi is £555), so way cheaper than the new Garmin Rally which are ~£959 for the double sided version.

I’ve just looked at the 4iiii (£377 for the single, non-driveside R9100 crankarm) and it should be very simple to install. Remove the pedal from the crank arm, undo the two pinch bolts on the crank and then use the little plastic tool (£3 in the UK) to remove the cap, at which point the arm will just pull off. Repeat in reverse to install the new PM crank.

As a side note, GPLama has a great video looking at Look cleat type PM pedals and cleat compatibility:

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