Canyon frame with GRX groupset - Any PM recommendations?

Hello all,
I am new to Trainerroad and also just back on the bike after a long period off. First time indoor training and just taking up Gravel after long time on Road and MTB.

After now training with my Wahoo kicker for last month, and trawling through the forums and listening to podcast, I want to upgrade to having a PM.

I have read the lengthy forum topics on Left-side vs Right sided PMs, as well as the different PMs people are running.

However need you’re expertise. I was looking for an entry PM that I could start with. Have one main bike and my Kicker core indoor. Looking at Left and maybe upgrade to right with my GRX810 groupset. I have a 2021 Canyon Grizl Gravel bike running with Shimano SPDs.
Clearance is tight to chain stay and 4ii would need a factory install, and Stages looks tight when I measured.

Options I think I have (where I need your advice):

  1. 4ii precision - checked and this would need a factory install due to LH clearance OR people seemed to have either bought Ultgra / 105 and with spacers and it fits? - would lose my Gravel bike for 2-3 weeks, which is not ideal before the race so prefer not the factory install.

  2. Stages LH - Looks like it is tight clearance, and have also read mixed reviews on quality and early issues on GEN1 and 2. GEN3 stable and worthy of an entry PM?

  3. Garmin XC100 (upgrade later to XC200) - Reading reviews they seem accurate, can transfer between my road / MTB bike but expensive (double price of 4ii).

  4. Assioma Duo hack - read the great thread on how to do it and looks straight forward… I would also get dual PM for same price as XC100, but means I would void warranties.

Any other options that people are running with a GRX810 groupset and a Canyon frame with tight chain stay clearance?

Hope you can help, and appreciate any help / advice you can give.



Hi Stu,

I have used the 4iii left side PM with the GRX crankset for the past few months with the Grizl (size small). No issue whatsoever with clearance.

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Thanks @rsusanto. Silly question but did you try the clearance check and it passed? I have a medium frame and tried the AAA battery test and it fails in the clearance zone from about middle to the crank.

I didn’t know that this test exists until you mentioned it. It sounds like I’ve been lucky. Even though I could have returned the crankset if it didn’t fit back then.

I was actually using the same PM crankset with my old bike for about a year, the Canyon Grail (also size small), and never had any issue. WIth the Grizl, I’d say, I have about a 2 mm gap between the PM unit and the chainstay. See photo.

Thanks @rsusanto. Looks plenty. Attached are my photos with the clearance guide attached and looks similar. Maybe worth looking at.

That is my Garmin sensor on the arm and that fits and that looks close to where your 4ii sensor is.

You are happy with the 4ii? My brother also has the same and seems happy with it so I think my preferred option due to cost and reviews.

Thanks again for taking the time to read and reply. Help a lot.

Yeah, you should be OK with the clearance. The pm unit would sit approximately in the same spot as where your current garmin unit is.

I’m very happy with the 4iii. I use Quarq dual sided pm on my road bike, and they produce approximately the same results. The 4iii is very easy to calibrate. I make it into a habit of doing it before every long ride.

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Thanks @rsusanto again. Massive help. Now looks like I need to try and source one here in Germany :slight_smile:

I have a 4iiii on my Boone with GRX cranks and I’d say it’s the way to go. It’s way cheaper then any of the Garmin offerings by hundreds of dollars. I don’t see the Garmin as any better unless you go for the dual sided, which are over $1000, or you have multiple bikes you want to switch back and forth. They’re pretty quick with the turnover (at least they were when I did it in 2020), and you can ride your road bike or MTB until you get it back.

Thanks @CaptainThunderpants. Yeah I think that is the preference, but looks like difficult to get a hold of one. Looking at feedback, not sure I need to do a factory install but as you said one option is just bite the bullet and do a factory install.

Cheers for the advice.

The benefit to a factory install, as shown in your photos above, is correct placement with your frame. They’ll ask for various photos of the cranks and frame to place the PM in the best spot so it doesn’t rub. I don’t think you’ll have any issues as the cadence sensor fits easily, but for me, there was a small space that mine would fit, so the factory install was the best way.

Does changing assioma pedal body actually void warranty? Favero even sells replacements pedal bodies

Looks like your crankarm are shimmed out…

I chose Vector 3 + Rally conversion kit for my Grizl, combo was cheaper than XC200 here.
Part of my desicion was based on that I can use them for my fatbike also, and 4iiii/Stages was impossible to find in stock.

Stu….I have the Garmin XC 100 pedals and I have been very pleased with their performance and durability. They’ve taken quite a few rock strikes and abuse. The thing I like about them is I can use them across all of my bikes (mtb, cyclocross, gravel, and road). I also use them with the bike on my smart trainer so I know that the power I put down on my outside rides are an accurate representation of my trainer rides.

quarq dfour would work great

Thanks @CaptainThunderpants.

Just what I was reading @ArHu74 but it was an older review and before duo-she came out with the spindles only…

@daniebr Yeah also struggling to find 4ii and Stages in stock, whereas Vector3/XC100/assioma are all stock.

Thanks for the feedback. Another option I could look at.

Thanks @fuuts for the feedback. That was one benefit I did see that I could them on other bikes as well as calibration with my trainer.

Just curious, can you not get a quarq with this setup? I have 2 bikes with quarq pms. Not cheap but they have been flawless for years.