GRX Power Meter Options

I tried to order a Stages factory install, but they cancelled my order because I am in Canada.

I use spd (mountain bike pedals) on this bike, and it appears that there are no options?

Any suggestions would be appreciated. Not fussed about dual side, and want the best bang for buck.

Thanks all!


you could use any hollowtech 2 left arm like 105/ultegra/DA. Not ideal because the arms not symmetric but it would work


Thanks for this…I do care about matching though. Vain perhaps…appreciate the recommendation!

Dealing with same issue here - and a stages PM is unlikely to clear the chainstay of my new Felt Breed. My current options at the top of the list are the favero assioma hack or changing the crank to an easton cinch system and PM. One option is ~$550 and the other is $1000. gulp.

Is there some reason you couldn’t use a power2max? The rotor3d 24 is the hollow tech compatible crack option for p2m.


Not sure if you’re open to changing and using PM pedals and cleats if you’re not using SPDs, but GPLama and a few others did this cool conversion…

…started from this TR thread => A Wild idea for Favero Assioma pedals


I am watching with this anticipation.

Or you could wait for SRM’s MTB power meter pedals.


I went through this same process for a Cervelo Aspero with the GRX groupset and landed on waiting for the SRM X MTB pedals.


Bummer on the Stages issue…I just ordered the Stages for my GRX, and am definitely looking forward to it. Haven’t even got it back yet. I think that’s the best, and maybe the only option. 4iii’s power doesn’t have an option available, yet.

So, I think it is SRM who is making an SPD style power pedal, and that would be rad. You could also get Garmin Vector, or Power Tap pedals and just use a pair of road shoes and cleats. I use mostly road cleats and pedals on my Gravel bike for long rides. Very light and smooth over long efforts. The only real reason you need SPD’s is for lots of on and off with hiking and mud/sand. Most true gravel rides have very little need for SPD.

The other option would be to go to an old school Power Tap hub. I think you can find someone getting rid of one fairly cheap.

I imagine 4iii will come out with something soon. Or, ship your non drive side crank arm to a buddy in the States, and have him send it to Stages.

Good Luck!

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4iii told me there were planning one, when I was asking about compatibility. One manufacturer told me the 4iii wouldn’t work on the gravel bike I was looking at, presumably due to frame clearance.

If I recall correctly @dcrainmaker and @GPLama have discussed that SPD is out of patent now/ in 2020 on the Fit File Podcast. Given that the Assioma hack seems to work, you’d have to expect Favero to be straight out of the blocks as soon as they can?


Frame clearance cropped up as an issue for pod-based crank PMs (Stages/4iiii) on a gravel build for me. I went with an Easton crank using their spindle-based PM. It’s a pricey way to go for a left-only PM, but it has no clearance issues, allows a full range of chainrings (2x or 1x, and direct-mount so not limited by BCD), and has worked great on an otherwise all-GRX build.

Easton makes the crank in both a carbon (EC90SL, $350) or aluminum (EA90, $120) model. The PM spindle lists for $599, but you can get it a bit cheaper bundled with the arms.


Not sure it matters in the real world, but Shimano moved the chain line out 2.5mm, for more tire clearance, with their GRX crank and front derailleur.

That may impact setup and performance with non-offset cranks from other brands.

You do have to be careful about front derailleur and crankset compatibility though – GRX uses a +2.5mm chainline, so Shimano says you need to run the GRX front derailleurs with GRX cranksets, and road front derailleurs with road cranksets.


Well I wasnt really convinced by the manufacturer - they were selling 105 and ultegra groupset options on the same frame with 4iii as a build option, yet told me a 105 left crank wouldn’t fit on the GRX build. My understanding was that the changes on GRX were all drive side. Anyway, went a different option in the end!

Hm, odd. I bought a 2020 Felt Broam with GRX and swapped out the new left crank with my old 105 crank that already had a 4iiii installed, and it works and rides just fine. The reason you couldn’t get a 4iiii for the GRX crank is simply that the new crank is concave instead of flat on the inner surface. The Breed may indeed have a frame clearance issue (e.g. like the Checkpoint) but I think Felt will know if you ask. As for appearance, the owner is likely the only one who would ever spot the difference between the 105 and GRX crank. Not having to buy a new PM was well worth the hit to vanity. :wink: In any case, the issue is frame clearance, not crank compatibility between GRX and 105. They’re interchangeable.

  • That isn’t stopping Stages from offering a factory install option for the GRX right now (and likely complete PM sales when the Shimano gets enough world stock).

  • And we’ve already heard that 4iiii plans to offer a GRX option in the future.

  • Point being that it is possible to do a LS GRX PM. The real issue is more likely the “newness” of the crank and getting all the right things lined up to make it happen.

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Though stages has said they can only do the PM on the GRX 810 hollowtech version, not the cheaper 600 version (which is concave).

Separately, I will just take my stages ultegra and try it. Both Felt and Stages said it wouldn’t fit on the Breed. It looks close. So I will just try it to see for myself.


Thanks for that clarification on the 2 crank versions.

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Yep, I wasn’t convinced at all, but Ribble were insistent regarding their CGR!

The GRX810 is flat on the inside and is the only GRX crank that can support a PM. Stages and 4iii have been telling me that they will have options for me “very soon”…since September 2. Now Stages is saying March and 4iii still has not received a set of cranks from Shimano to configure their PM so April/May seems likely.

As for vanity, I would totally be ok with using a 105 if I already had one, but since I’m going to get something new…I want it to match…OCD I know! Form over function? haha.

Thanks all for the banter and thoughts!