So I have a assioma uno power meter and I ve been using it for the past 4 months but where I live there is not any climbs so I couldn’t really check my times
Though last week I want for a trip to San Sebastián and did some climbing and I go much slower then expected at a given power
I am 54kg and the weight of my gear and bike is 13 kg
For example I did 3.6km 11.5 percent climb in 17:40 and pushed 315 watts avg, the calculator is saying that I should do it in aeroufn 15 minutes
One thing Is I am used to standing a lot so maybe that messes up the power?
Do you have any similar experiences? What should I do?
Yip, whilst standing gets more power out your less aerodynamic and often slower for more effort.
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Which one exactly? I ask because quality and accuracy there could easily be in question.
Beyond that, your own PM must be questioned for accuracy depending on install process and zero offset habits, and then the realization that single-sided is also a likely contributor since many people aren’t dead steady 50-50 L-R.
TLDR, power is not as simple and guaranteed as we’d hope.
That’s the one that I used
Regarding the power meter I made sure that it’s properly screwed and calibrated it through the Favero assioma app and also I can’t really believe that it would be like 25 percent off
I can understand 5-10 percent but more then this would be ridiculous
Yes I know but don’t think aerodynamics matter so much on such a steep climb at speeds under 15k
It’s surprising but as I was suggesting you also put out more power standing up which not only fools formulas but sees you expending more energy/ power in a up & down movement supporting your weight rather than a forward movement where the bike supports your weight.
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Right. You can put out higher peak power standing, but it is less efficient and not sustainable. Standing is good for short sharp ramps, sprinting, and to take a break from being seated. All decent modern PMs will correctly measure power seated, standing, pedaling with one leg, only pulling up, etc. (edit: I should add that single sided do this, but only for one side with the obvious effects.)
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Amazed you are so concerned by this, there’s so many variables going on outdoors it must be so hard to actually estimate properly.
I made myself a climb estimate calculator that tends to predict very well except for really short, high power climbs or low gradient climbs (where aerodynamics become too significant to be accurate) - I input the data you gave and it’s giving me 16-16.5min depending on rolling resistance. One thing with climbs that steep is that the overwhelming majority of power goes to moving you uphill, and small changes in power loss can make significant differences.
For example, at 15W rolling resistance it gives 15:52, while at 25W rolling resistance it gives 16:27. I left the aero drag at 10W for each. Was there a headwind? That could easily put you over 17mins.
No there is no headwind
Though the bike that I was riding was a one with a cheap aluminium frame and wheels
So maybe when I am standing at low rpm 55-65 the torque is causing the frame to vibrate and bend and the power is lost
I don’t know
Have you properly considered the L/R power balance as pointed out by @mcneese.chad ? 315 watts means your one sided PM is recording 157.5 watts and doubling it. If you have, say, a 53/47 imbalance favouring that side (and I don’t think that’s at all uncommon or extreme) that implies an actual power average more like 297 watts does it not? How does that impact on your climb calculator?
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Yes, it’s details like these that are the unstated assumptions and influential variables that can lead reality (messy) to deviate from calculations (simple… sometimes to a fault).
I doubt there is enough difference in those alone to account for the delta, but they likely add to the whole picture. Skimming the calculator you linked, the one that catches my eye is Rolling Resistance. As we have seen over the years, tires can make a MASSIVE difference to speed and timed efforts like this. I won’t say this is the biggest source of a delta here as I really don’t know that calculator, but it shows that there are always many factors at the root here.
For anyone really caring about estimates like this, I’d think that using Best Bike Split is the proper choice. But any further analysis here could hinge on what you plan to do with this info now or future efforts. If it’s not really aimed at nailing down future efforts, I’d just blow it off as math falling short due to the complexity hiding in plain sight. If you really need to do more with this, I’d push towards a better resource and proper including all your gear to narrow the real vs calc delta.
I tried using the calculator you linked and it was wildly too fast for me.
I plugged in values for a climb I did last week.
My spreadsheet estimated 84:11, and climbapedia.org gave me 78:30. The climb actually took me 83:54.
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Also you have the one sided power meter variable. I had this problem with Stages back in the day.
Coming from a crank base PM to single sided I started seeing some weird reading that I wasn’t used to.