Power Meter options for MTB
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- Posts: 121
- Joined: Sun Jun 30, 2013 6:05 am
I have a Quarq PM on some X0 carbon cranks. Apart from my missing the 24T granny ring (minimum 26T on the PM - I have steep terrain in my area) it has been flawless.
How do I find using a PM on the MTB? I doubt I'd do it again.
I bought it because I had a concern about overtraining after having almost every race I intended entering interrupted with illness last winter. Being more disciplined with internet use and getting more sleep this season has helped a lot so far.
I find the TSS (TrainingPeaks) is understated compared to road by 20% or more, because MTB uses so much more upper body and core compared to road for the same effort. Whereas if I use HR TSS it seems about right.
I never get to watch the numbers on the MTB - trying to do so is a recipe for crash and injury. It's only any good for post-ride analysis, and is limited by the issues mentioned above. Save your money and get some coaching instead.
On the road bike, yes PMs are very useful for training. I have one of the new model P2Ms on some Rotor cranks with non-Q-ring chainrings, and it just works. Particularly good for short HIT intervals, much better than using HR.
How do I find using a PM on the MTB? I doubt I'd do it again.
I bought it because I had a concern about overtraining after having almost every race I intended entering interrupted with illness last winter. Being more disciplined with internet use and getting more sleep this season has helped a lot so far.
I find the TSS (TrainingPeaks) is understated compared to road by 20% or more, because MTB uses so much more upper body and core compared to road for the same effort. Whereas if I use HR TSS it seems about right.
I never get to watch the numbers on the MTB - trying to do so is a recipe for crash and injury. It's only any good for post-ride analysis, and is limited by the issues mentioned above. Save your money and get some coaching instead.
On the road bike, yes PMs are very useful for training. I have one of the new model P2Ms on some Rotor cranks with non-Q-ring chainrings, and it just works. Particularly good for short HIT intervals, much better than using HR.
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they measure deflection of the crank arm.
Jaker wrote:Does anyone know why the Stages power meters can't seem to be used on a carbon crank? Does it have something to do with how rigid carbon is? Are these things measuring strain in the crank arm?
Carbon doesn't react to force as predictably as aluminum does. Additionally, the bonding surfaces tend to be less flat
It's likely possibly to do, but making it a product is much more difficult given stages and 4iiii's inability to support carbon cranks initially.
It's likely possibly to do, but making it a product is much more difficult given stages and 4iiii's inability to support carbon cranks initially.
I would think it'd be a simple as installing the power meter, setting it up in their calibration rig, applying a known force to the arm and setting the meter/strain gauge appropriately. Then again, I'm not 100% sure of their methods.
That is essentially correct. To get around that, manufacturers mount carbon arms to an alloy powermeter chassis, which works fine. I love my SRM and have had good results with it, though I know some have had issues with the MTB versions. I am still running an older wired version, which has been really reliable.
I've also had no issues with my Xt Stages, bar a couple of battery changes.
Weight 74.4kg, FTP 303W => 4.04 W/kg
Retired Bikes
Custom 650B Kingdom Double9
Kinesis Aithein / Kinesis Racelight 4S
Current bikes
Reilly Spectre / Cervelo R3
Pivot Les / Pivot Mach4SL
Ventana El Conquistador
Retired Bikes
Custom 650B Kingdom Double9
Kinesis Aithein / Kinesis Racelight 4S
Current bikes
Reilly Spectre / Cervelo R3
Pivot Les / Pivot Mach4SL
Ventana El Conquistador
- Vallinotti
- Posts: 91
- Joined: Mon Sep 21, 2009 11:12 pm
Hi all,
I'm looking for a powermeter for my new Trek Top Fuel 9.9SL. However this boost 148 standard is problem in selecting a crank based powermeter for a 1x11 drivetrain(XX1) it should have a chainline of 52mm but this information is not open wide in the Internet . Could someone which have a pm with gxp or 24mm spindle with Q factor larger than 160mm inform me the chainline measurement of your PM?
I'm looking for a powermeter for my new Trek Top Fuel 9.9SL. However this boost 148 standard is problem in selecting a crank based powermeter for a 1x11 drivetrain(XX1) it should have a chainline of 52mm but this information is not open wide in the Internet . Could someone which have a pm with gxp or 24mm spindle with Q factor larger than 160mm inform me the chainline measurement of your PM?
I still think if you calibrate your testing rig with a known accurate aluminum crank arm setup, and then throw a carbon arm into the machine and measure the "output", you could easliy calibrate these things to a carbon crnak arm. Then again, I'm not an engineer.
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- Posts: 283
- Joined: Sun May 31, 2009 5:07 am
I had a Stages on my mtb and sold it after half a year. It worked well but it took away the joy of riding my mtb. IMO power is for the road unless you only ride mtb