Power2Max NGeco on the mtbs have been flawless. Would equip them the same way again.
Tried the Garmin XC Rally and SRM XPower on the mtb against the P2M, staying with P2M on mtb and went with Favero Shi hacked for SPD on the gravel bike.
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As mentioned below, that depends a bit on the power meters in use and how close they are. If they are in the same basic range, yes, using similar power zones may works.
But keep in mind the other factors that may come into play like inside vs outside use, high vs low rolling/flywheel speed and such.
I posted a few up on if I will get power for my MTB that I just got. I am giving it a few months before deciding and have my garmin speed / cadence sensor 2 on there. For my use case initially I am leaning towards not getting one.
Road is a little more relative for me as I do have fun with a few strava segments every now and then which as PM is useful. If i do decide to get one I will have another 4iiii left crank and my road bike one has been flawless for 3+ years now and just works.
What did you not get from single sided? Sometimes I wish I had dual sided especially for workouts but single sided offers a lot. Certainly not useless.
why not? Seems a little arbitrary to say close isn’t good enough with power. We’ve all been accepting a fairly wide range of accuracy on powermeters in all platforms, not just single-sided or double-sided. Different power meters and different trainers all have error ranges both advertised and not. I’d say Precision matters, accuracy is relative.
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How did they track? Just Curious. I like the SRM pedals as I can move them around and after that initial update are working well.
I find that power spikes are one of the biggest problems with singled sided PM’s, especially off road.
Then you also have the fatigue factor and how you pedal at different wattages. For example, you might be 50/50 @ 100 watts but 40/60 @ 300 and that could all change after 2 hours on the bike.
Wrong. We live in the middle ground. Can you tell the difference between a power meter that is +/- 2% and a single-sided power meter that is +/- 1%? How often do you recalibrate your power meter according to factory procedure to be sure it continues to be accurate? If you put three power meters on your bike in different places, would they all read the same? Should they all read the same? If your power meter is perfectly accurate and precise, is your ability to produce power today the same as it was yesterday, and as it will be tomorrow?
A whole power meter is going to reduce the margin of error relative to a single-sided power meter, which is good. But a holistic awareness of all of the ways your power data could be misleading a person can lead them to make a different informed, reasonable choice about the cost/value tradeoff of whole vs. single-sided power meters than you do.
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Leg imbalances aside, I really don’t see the problem with single sided meters. I’d like one, for sure, but a dual sided meter isn’t the missing link for me personally. For most riders, a single sided meter is still better than no meter.
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Found the SRMs to be pretty “spiky” and interval between charging really short. They read higher than the P2M. The Rally XC (even before the firmware update in Oct/Nov) read much closer to the P2M (as do both of the Duos). I hope Favero can come up with a smaller pod variant with a contemporary Shimano SPD spindle variant. The ease of moving them is so much nicer with the spindle hollow vs the flats on SRM and Garmin Rally. Getting proper torque is simpler and not as critcial as well.
I’ve been using Shi DUO with Shimano EH500 bodies on the fat bike this winter (until I tore my MCL XC skiing). More of a curiosity application on the fat bike than for training info. Don’t have a P2M on that so no comparison.
Purple is SRM
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First, I removed my post challenging your position because I saw that you did provide some background, so sorry about how that came across.
You’re using your personal experience to cast a very wide net here. I think it deserves to be challenged that “single sided meters are useless” - that’s all.
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Anyone using a PM on their trail bike? I have a Quarq on the XC bike but just got a new Stumpy Evo and I am wondering if its worth the $ to add a PM to it.
@smlring what do you do with the info about imbalances? Do you do specific training to address the imbalances? I bought a single sided meter as I figured I only care about total power I can produce for a given effort at a particular point in my training. What is the utility of knowing contribution by each leg? How have you incorporated that knowledge into training?
Is that a calibration, or a zero offset? You clearly have the free time and budget to do this, but is your argument also that “training without a power meter > not calbrating your power meter every 6 weeks”?
Oh, they have done great work on establishing all the ways power meters can mislead you. DCRainmaker wrote an article a few years ago that does a much better job of addressing all the ways power meters can mislead you than my earlier comment could hope to. Not surprisingly, from a power meter accuracy standpoint single-sided power meters force a loss of accuracy that might equal the loss from a dirty drive train.
But… as DCRainmaker also likes to point out,
I’ve also noted that training with a power meter that’s a few percent variable is definitely better than no power meter at all. If you can afford a full power or dual-sided power meter – great! But, if you can’t, or if this is perhaps for a bike that having perfection in your numbers isn’t as important, then that makes total sense.
For doing research on physiology or sports performance, a single-sided power meter would need to work extra hard to generate findings with any confidence. For useful data to train on… the standard is much lower.
As a last note, your edit did not “fix” anything. It just ignored the point that our physiology day-to-day changes, so even if you have complete confidence in the number, the window it provides into your physiology and capability is imperfect and ever-changing.
If you’re not training or racing on it then probably falls into the “nice to have” but not needed category. Once you have power on your bikes it can feel odd/off to not have it, even for nothing else other than curiosity sake. So for a trail bike I’d probably pass unless I have money to burn.
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Did you confirm that a single sided powermeter fits the Epic Evo?
In the market for a budget powermeter for that bike myself.
With all due respect, you’re being very confrontational for someone who said they didn’t want to be confrontational.
I think it’s fair to say you prefer dual-sided PM’s for an added layer of data, I don’t think it’s at all fair to suggest that anyone who chooses single-sided has made a poor, or incorrect decision. It’s certainly not fair to question people’s knowledge of their gear and training because they’ve made an alternative choice to you.
For example, questioning JSTootel is crazy, he’s an elite level mtber, leg balance is almost worthless as a metric on the single track (imo)
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You could say the same about any outside data.
Unless you’re in a controlled environment I think worrying about erroneous data at that level minutiae is missing the forest for the trees.
Who’s to say you hadn’t gained weight, had a different wind, air pressure, humidity, temperature, tyres.
Since it is an expert and SRAM I would need to take the crank off and send it to 4iiii as they don’t have any ready made currently. I don’t have a problem with this as the turnaround good and less amount of $$ as well.
A single-sided power meter does not give you the full picture. A complete dual power meter also does not give you a full picture. So, for an incremental increase in price, you get an incrementally fuller picture. Recognizing that you are always dealing with an incomplete picture is an important step in making a reasonable decision for your circumstances about what (if any) power meter to buy.
Mountain biking is even worse, because more of the effort and strain occurs outside the drivetrain, meaning that the relative inaccuracy of a single-sided power meter is also a smaller percentage of the whole.
If someone told you, “believing that single sided power meters are bad is fine. Just do not try to convince others,” how would you react? You have no authority to tell anyone what power meters they can and can’t recommend, and you should stop pretending you do.
Anyway, I’ll say “thanks” to @Jason_Kennedy for his video on the Power2max, which is the whole reason I was looking at this thread today. I’m still trying to decide if I want to add power to my mountain bike, and it’s a valuable data point about what I had assumed to be the durability of a spider-based PM vs. a pedal-based PM. If I need to consider the PM on my MTB to be somewhat disposable, then maybe going with a cheaper single-sided pedal option is smarter.
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