Pedal based is not an option for mtb cleats. Rim powertap cannot be converted to a disc hub, requires different hubs completely. Your best and really only option is crank/spider based.

But if you have three seperate wheels with power, it could also be worthwhile to sell one and buy a disc powertap, if you're fine with having only one kind of rear wheel with power.

I run a stages, easiest one on the market to swap between bikes

Thanks for the reply.

You confirmed my fears about going to crank/spider-basked power. That's something I was trying to avoid. Argh.

I have been very pleased with P2M (type S) for the cross bike. Just bought the spider and installed it myself. Of all the PMs i have tried so far, it is the one requiring the least hands on. And it was easy enough to install. No issues.

They are now launching the NG version, so maybe either wait for that or look for deals on type S.

Thanks. So, it seems like crank-based power is the route most cross/gravel bikes have because rear wheel power is not as common and pedal-based is not an option.

I'm assuming you are looking for 'precision power' - but I thought it worth noting how I filled on the power blanks on my non-road bikes.

I picked up a PowerTap PowerCal HR based power meter which runs about $100. It simply uses your HR and some math to estimate Power, but it is reasonably accurate. Compared to my PowerTap files from my road rides, anything over an hour usually comes out within a few watts on Av Power and Net Power. I keep meaning to ride with both - maybe this post will be the stimulus to compare the two on the same ride.

There is more going on than a simple curve, for example: For me Z2 is about 140 BPM and 175W. There are several cases where my HR would be at 150, but with varying power outputs.

Accelerating from a stop: HR rapidly increases and Garmin shows a very believable 350W or so.
Climbing a hill : Steady State effort shows power at 225-250W
Cresting a Hill: A hard climb followed by a coast-down may see my HR go from 175 down through 150
- Coasting down, (rapid decrease in HR) Power gores to 0
- Soft-pedaling (gentle decrease in HR) power may read 100W

There are clearly some flaws - standing at a red light i'm usually 'putting out' ~50W and I would never claim a brag number for a new FTP or Avg power (CP30, etc...) Sharp efforts are masked due to HR response lag and I don't think I've ever seen a figure above 600W on the PowerCal where I can hit 800-1000 for a few seconds on my PowerTap.

So it is imperfect - but over the course of a 45 minute cross race or a 5 hour MTB race, the numbers are believable and help me fill in blanks I would have in my records otherwise. I also took it to Moab recently for a few days of biking on a burly rental bike - try that with a Quark!

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" I take my gear out of my car and put my bike together. Tourists and locals are watching from sidewalk cafes. Non-racers. The emptiness of of their lives shocks me. "
(opening lines from Tim Krabbe's The Rider , 1978

I suggest a crank based powermeter like PM2 or Quarq.
I had a Stages on a gravel bike- the weakness of the Stages is that power fluctuates wildly (because it is one sided)- this becomes even more noticeable with high torque in offroad situations.

I talked to Stages at length about this. They admitted that that is "how it is" and that it works well enough for most people. I guess I am not most people???

I went with Stages on my CX bike. Been happy with the results compared with my PowerTap that I used when I had canti brakes.

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Twitter @achtervolger

You seem to be a PowerTap guy. Is there a reason you are not considering the C1? It's a great PM at a good price from a great company you already deal with. The only problem is it only comes in 110BCD, but I assume your gravel bike is 110 already? Should be an easy reasonably priced solution.

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"...the street finds its own uses for things"

Curious to see what recommendations are made here. I run 11sp Ultegra cranks on both my road and CX bike. Due to local topography, I have no interest in running 1X on my CX bike. Last year I was looking for a single powermeter to change seasonally. If I recall correctly, the only satisfactory option that would allow 46T/36T option was Quarq. I haven't had good luck with any SRAM product so I abandoned my search and still don't have a powermeter.

+1 to this. Mine has survived a couple seasons of these types of conditions. The same PM has been set up with a 52/38, 50/34, 46/36, and 40t 1x on 3 different Rotor 3D+/3D30 cranks. Power2Max PM's just work.

Have you considered using road pedals & shoes on your gravel bike? Cyclocross requires mtb pedals/shoes due to the times you get off & run, but dirt/gravel riding is essentially the same as road riding in terms of the amount of walking you do (i.e. - it's just for rest stops and the like). Many people swap in road shoes/pedals for climbing-heavy events like Crusher in the Tushar because they're lighter and stiffer.

I was thinking about this. But, sometimes during gravel racing, the terrain gets pretty dicey (e.g., deep car ruts or sandy) and I might need to click out very fast to run with the bike for a short time. Even though that's not often, that would be very harsh with road cleats. Also, I just bought an awesome pair of cold-weather mtn cycling shoes, which I would have to replace for the road version. That's not a deal-breaker necessarily, but it's a factor.

Truthfully, I haven't thought about it, and I don't even know what "110BCD" even means. I'll look into it, thanks.

Agreed.

As of right now and based on awesome ST feedback (thanks), it seems like the P2M is the best option, and to wait for the next NG version.

This is only a solution if you are okay with the small ring being a 36 tooth. I don't believe they go smaller. And the smallest large ring is a 50t. That should be fine for most gravel riding, though.

BCD - Bolt Center Diameter. It describes the length of the crank web arms (kind of, in loose terms). Most people use the term standard or compact crank, but that is really a misnomer of sorts.

If your big ring is smaller than 52, or your smaller ring is smaller than 38, you have 110 BCD crank on your bike. You can put bigger rings on a small crank, but you can't go the other way.

Power Tap only saw fit to make its C1 power meter in a 110 BCD configuration. That combined with a set of Praxis rings should work perfectly on a cross bike. (I just Googled the bikes and looks like 46/34 is a standard setup, so they have to be running a 110 BCD)

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"...the street finds its own uses for things"

I put a Stages on my cross bike. I just wanted something for "good enough" ballpark data and found one really cheap on closeout. (All of my other testing and training is done with a different bike with a PT). I've been happy with the Stages. Occasionally I get wonky readings if I'm riding a long rough section but that's pretty rare. If I had to do it again, I'd once shop by price and would be OK with another Stages.

I have a Power2Max on my TT bike (on Rotor 3D cranks: not plus - 25mm spindle). It does just work.

I've never had a cross bike, but was thinking of getting one. Is the bottom bracket shell width the same as road/TT? I had assumed the bottom bracket and Q width would be different in cross bikes, like they are on mountain bikes. That would make it hard to transfer between bikes.

Definitely don't give up your MTB shoes/pedals. Gravel riding takes you to all sorts of wonderful places, some you can handle, some you cannot, some you don't know until you get there. One of the big rides I did this year was 'basically like road cycling' except I had to ford a large creek. Actually, that happened several times.

Crank meter is probably where it's at, heed what others have said re: Stages. Grinding up steep climbs I sometimes can end up with cadence down in the 50-60's which I can see a one sided meter having problems with. Whatever you do, make a choice that maximizes your flexibility for gearing. As you pick a crank make sure that any rings you might want to buy are available for it.

I'm glad to hear that you are having luck with your power cal, I am in the same boat I have a SRM on both my road and TT bikes but wanted something that would "ball park" it for both my MTB and Gravel bike, and I have to say that after using it 3-4 times it's just sitting on my shelf collecting dust, the numbers were so far off that it was pretty much useless to me.

Quarq on my current CX rig. And I'll put another one on my new CX bike next year. Love it.

Bad idea. I have seen several roadie shoes get cooked walking over rocks or people go down and get hurt from slipping on their carbon fiber disco slippers.

Unless the "gravel/cross" riding is mainly pavement with 28's dropped allll the way down to 90psi, shoes that are walkable on stuff that isn't ridable is the way to go.