New Power Meter for CX Bike: Quarq vs Power2Max

Looking to get a power meter for my cross bike, a Trek Boone. It’s got Shimano cranks on right now so I can do a Power2Max with Rotor cranks. The other option I was considering was a Quarq on SRAM Red AXS cranks. This would require a GXP BB change, which is a discussion in itself. I know some people hate the GXP BB, but many don’t have any complaints. The Quarq/SRAM is more expensive but I’ve been considering upgrading to AXS in the future for 1x12, and this would be the first step. Any thoughts?

Don’t think you can go wrong with either choice. Quarq and p2max are both great options.

That said, both of my bikes are p2max w/Rotor cranks. Never an issue other than the occasional battery change.

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P2m has a new PM/Rotor crank combo for $590, which is like half the price of what it’d cost for SRAM Red and a Quarq. Actually, as I’m typing this I’m kind of wondering why I’m even considering the Quarq.

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You can use GXP with a shimano BB with a shim on the non driveside

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I thought the shim had to be on the inside, meaning you’d need to remove the bearing first.

I’ve only had one issue with my Quarqs, and it was because it was super old. They ended up replacing it for me. I’m a big fan and since I’m so familiar with them I’d find it hard to go with another brand.

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You can use a shim to make the 22mm non drive side into a 24mm axle https://www.amazon.com/Dilwe-Bracket-Adapter-Aluminium-Bearing/dp/B07DWQKHPV/

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Ive got a quarq on my CX bike, been going strong for a few years now. Wouldnt mind trying a P2M either though, dont think you can really go wrong with either

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The GXP BB is nothing but excellent and that would be a big plus point for me.
I’ve seen good data from both Quarq and P2M and I would happily run either. FWIW, I’ve used loads of Quarq PM’s without issue.

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I’d go Power2Max, save the money you’d spend on Quark/SRAM to put toward the AXS upgrade kit or a different upgrade. No reason IMO to upgrade cranks when you go AXS, just get the upgrade kit (derailleur and controller) and a 12-speed cassette.

All that said, I’d consider whether you really need power on your CX bike. If you use it for road/gravel training that’s one thing, but if it’s really a CX machine I personally don’t see the use for power all that much, and the PM spider adds a significant amount of weight. I put an P2Max on my CX bike and ended up removing it to go back to the integrated crank/spider and save a bunch of weight.

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I’m not too worried about weight. And it’s not a lot. Compared to Ultegra cranks, the P2M would add around 100g (Ultegra w/o rings: 549g, P2M w/o rings: 645g). The Quarq/SRAM combo (power meter included) is actually lighter by around 20g, so if I was really concerned with weight, I could go lighter and get power that route, but it’s twice the cost.

I recently sold my main road bike, so for now, my Boone is doing everything. So really, I’d like to have power for outdoor training riders as well as data collection of races next season. I’m leaning towards the P2M right now.

If it’s your main bike you absolutely need power! I’m very happy with the Power2Max (on my gravel bike now).

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I have the quarq with force axs on my boone and its been fantastic so far. I chose it partly based on GPLamas review of it

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I recently put the Power2Max on my Trek Crockett and it was super easy and is working great. I looked around at a bunch of options and the P2M just made sense for cost and reviews. I already had SRAM Force 1, and just had to change the chainring. So that was a little easier than your situation.

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As it is now, that’s all I’d need to do also. The Quarq is actually a little more work switching over to GXP. I’m leaning towards the P2M based on price ($590 vs ~$1100) and easy swap.

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Can you even buy AXS compatible chainrings to go on a 5x110 crank (I assume thats what is on the P2M)? Or are you running regular 11 spd?

AXS chains have larger rollers than 10/11 speed chains so require different chainrings, which AFAIK can only come from SRAM at this stage

EDIT: just read the OP again, looks like Shimano 11spd group, so all good!

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If you’ve got a Shimano crank, you’re really need a good reason to spend more than $300 on a Stages (or similar). Otherwise, Favero power meter pedals are the hurdle out there before looking at a crank PM.

For CX, there’s no reason not to get a used PM you can beat up. If you’re looking to play around with your groupset, pedals are the way to go. I’ve got both and they are both capable of fording streams.

Going GXP is no big deal, but does require some labor or a spacer.

On Quarq v Power2Max-
I’ve got both and functionally, there’s no difference. The P2M is a tank, the Quarq is just very durable. The P2M has a less finicky battery tabs, but that will vary by version. P2M’s battery cover is easier to get yanked off (hasn’t happened to me), but quarqs is easier to leak.
On the exact version, buy one that doesn’t need a particular chainring pattern by the bolts, one that can accept a full circle of metal, not the tabs coming in. This will make it easier to find chainrings. I have an older Quarq that couldn’t accept some clockable oval rings.

Crank
On the crank, Rotors are nice pieces (the $590 rotor/P2M Aldhu is the way to go here), but I’d get a 3-bolt SRAM setup for the following reasons - if you want to change arms lengths, there are a million used Sram crank sets on teh market for $60-75. There are not a million Rotor 24 cranks. The SRAM will be easier to sell.
(Used only) The Rotor 3D and 3d24 needed a special tool to remove/install the spider, the Sram does not - not sure about the new Rotor. The older rotor had a different 24 and 30mm spider interface, the Sram is common so you can move to a different bike more easily.

Consider getting a used unit in the smallest BCD you can. If you’re a TT buy, get 130, otherwise 110bcd for use as it be a lot more flexible. I"d get the Shimano 4-bolt pattern over the 5-bolt pattern for chainring options.

I wish I could. I had a Pioneer crank arm PM, but mounted on the Boone, it left around 1mm between the PM and frame, and I didn’t feel comfortable racing CX with a clearance that small. I tried adding a crank spindle spacer, but I couldn’t push the retaining pin in on the non-drive crank arm. I believe the 4iiii is thinner but not sure.

Considered this with the CXR/Assioma hack, and I actually posted my result with it last year. I bought new Shimano XC9 shoes and honestly, don’t want to hack up $400 shoes if there’s a better option. Also, a little scared about pedal strikes but they did ok in the 1 race last year I tried them in.

This is what I’m probably going to do. Though, I was considering the Quarq DFour91 that has the Shimano chainring mounting just because it’s cheaper and everything I currently own (1x and 2x) is Shimano. And it’s $506 at CompetitiveCyclist right now.

Edit: Are there any real world differences between the new Quarq AXS PM and the DFour91?

no other than the direct mount non replaceable chainrings

The 1x has replaceable rings. But now that you mention that, it would be a 1x only system.