Yup.

cant answer with numbers but in my experience its a big difference, also hard to maintain power if you're bouncing around

There's a road near where I live that part of it was resurfaced recently, but part wasn't. To hold 150w, 4-5% gradient the speed jumped from 13mph to 16mph. Literally right after each other, straight road, so no condition changes or anything. So I'd say it was pretty accurate.

most of the area I live in have terrible tarmac, riding is fun but hard

the only problem there is finding a section of smooth road to do the comparison. it might have to be rough vs slightly less rough instead

that's just common knowledge, it's well documented that jumping from a Cannondale to a Trek gains 20w

Ryder Hesjedal disagree ;)

@@sputnic3032 not anymore, see www.cannondale.com/~/media/Files/PDF/Dorel/Cannondale/Global/SystemSix_Whitepaper.pdf Cannondale SystemSix is more aerodynamic than Trek Madone.

hahahaha

*checks list of sponsors in description* yep

+Mr B I've got no issues with the fact they are a business that has to get income. My issue is that they clearly talk down stages, without mentioning them, which is out of order! For the average weekend rider stages might be the cheapest but is still bloody expensive!! Most of us just want a rough idea of power.

+The axe man!! I have a Garmin 520 with speed and cadence sensor also use estimated power app on the Garmin. I have compaired it to people using power meters and it seems pretty good.

Agreed,Sky would`t use a power meter that was shit,after all Sky are probably the tech leaders in the pro peloton.

You really should consider it. Much more aero. Hand-pedaling truly is the future.

mate 😂😂😂😂😂😂😂

LOL I didn't even know he said that.

😂me too

Best climb face

Yes hey can, but you are talking about relatively small deflections so the fatigue cycles are quite high. Very similar to a pressure sensor used on your car which measures the deflection of a diaphragm using strain gauges. Vibration fatigue is likely a bigger issue than stomping on the pedals.

this also means that the power meter must contain a section which bends or flexes to allow this sensor to flex? surely this then reduces the efficiency of the part - some of your pedal stroke is wasted on bending the crank/spider rather than turning the chainrings?

It's your crank that flexes and the strain gauge foil is glued to the crank. The stresses in the crank are higher that the stresses in the thin foil.

For example metal fatigue in aluminum will happen with even the smallest bend but in steel there is a 'threshold' you can bend it within some limits and get no metal fatigue. I don't which metal is in power meter but if I were to design them I would use one that has a no-fatigue threshold.

The movements would be quite small I suppose, but I don't know exactly how they are constructed.... and where and how any possible metal fatigue could occur.

That 10% is on the high end of a test that is itself in the high end... just like every single number involved in cycling. "our pants reduce wind drag by 40%", "drafting behind another cyclist saves 30% of your effort", "our helmet increases your time by 5 seconds over 50 miles", "our wheel reduce power usage by 7 watts"... you get the gist. The numbers are technically true but they also make for a more interesting story so companies, journalists, and even you and I choose to parrot them. It's not a conspiracy, its human nature.

You will find sky are paid big dollars to run stages, and prior to that they actually had to buy their SRM units. At my club, I don't think a single person has had a positive experience with stages with battery drain issues, inconsistent data output and several warranty replacements.

+JM AF a local SRM dealer I know said something like 40℅ of SRMs get returned for warranty issues in the first 6 months.

when I mean data, data accrued using the same power meter.

Would Team Sky use left sided powermeters if they are crap? No. I am perfectly fine with my Garmin Vector S and my two stages powermeters. No need of double sided versions... :)

I know with my LEFT LEG power meter I need to get to a number on my LEFT LEG power meter that I can stick with for what ever distance I am doing eg 30km TT i know I have to range 300 - 350 watts on my LEFT LEG power meter, if I go above this number I might be able to do it for 2-4 minutes but have to drop down to the 300 and not very far off it or I go into the red can't recover and my time will pay the price - to me its me racing against me with the numbers provided I know what I can get and cant get and I always try to push the boundaries so I can let my numbers rise by very small amounts but over a long period them same small amounts are large. 5 watts a month == 60 watts by the end of the year that's like getting a newbie cyclists leg and sticking it to your own for an Xmass gift to yourself.

from my experience over the last 4 years there are 3 big issues with left only that I have noticed from my power2max estimated L-R balance. 1. left and right balance varies depending on intensity with me riding at close to 55-45 at easy intensity and almost perfect 50-50 at FTP or higher. 2. if I have an injury such as a sore knee, I can be as bad as 40-60 3. in longer rides my left seems to fatigue faster than my right, which shows in my L-R output.

good enough for sky.... it will depend on the rider my stages numbers are very close to wattbike numbers so i dont worry about it

strava power is sometimes off by like 70 or more watts which is huge.

Strava is only a rough guess it can be almost correct if you, your bike and the environment meet certain conditions, outside of this its very inaccurate. personally if on my own on a cycle I found it to be below what I get on indoor training power meters, tack neo 2800 and stages power meters. (tacx neo not a power meter its only a rough calculation but it can be accurate) i have tested it against the stages and they are almost the same there are some fluctuations but not very often.

Strava does not know what the wind is doing and can also completely get the road grade wrong. I was once given 1400w for a few minutes going up a slight hill with a tail wind.

The practical life of a strain gauge is longer than your frame. Check out this guy who made his own power meter: keithhack.blogspot.com/2013/01/v3power-meterthe-complete-how-to.html and you can see how little to stress is applied to the actual strain gauge. Strain gauges exist in all kinds of places from bridges to mining safety gear and will operate 10s to 100 years or more. The electronics that read the data, can fail, but the actual strain gauge probably won't, unless it was faulty from the get go.

+MKTech very good to know. Thanks! 👍

Jeez Milbs they are just trying to make it easier to understand! For us, non engineers folk, force is quite intuitive, whereas torque is quite more technical

I agree. My eyes where bleeding 😭

***** I know, but it was painful to listen to!

It would not really mean much as 'better' is hard to quantify between road and MTB. MTB tends to have much more high peak power for much shorter periods of time, where road requires the rider to hold power for a longer time. That is, it is possible for a MTB rider to best a roadie about peak power, but a roadie will likely have a much better 20min/40min/60min power.

they already did

they have made such a video

which bike upgrade to do first: power meter or wheels?

In my opinion, if you want to enjoy your ride more and go faster/further, wheels. If you are serious about training and really like to look at the numbers then go for a powermeter.

You think wheels, rather than the most precise training device in any endurance sport, will allow someone to go farther and faster? Lol. Wheel weight has virtually no effect on climbing and the drag produced by wheels is negligible, even at high speeds. Upgrading them costs big money and has tiny effect on speed.

Depends on your wheels - a good alloys wheel set will stay truer, with better his will roll easier and with enough spokes, depending on your weight you get a much more dependable wheel that rolls easier and makes the most of your hard earned wattage. Power meters are great for training, but for overall riding you can't beat a good set of wheels.

+Rob Lucchetti ^ it really depends what you want. If you aren't serious about training and just enjoy riding, a power meter isn't going to do a whole lot, which is why I said in the first comment that if you are serious about training a power meter is a good idea!

Thank you for that. You give me hope that I don't suck as bad as Strava says I do. :)

strava sometimes claims i hit 1300 watts, which is soo wrong. my stages reports max of like 700 watts. strava uses stupid math

I think my budget is within two months of adding a power meter to my bike. My research has me leaning strongly towards the Stages. How do you like yours?

Watch this and then decide (hint, Quarq)... www.bikeradar.com/us/road/gear/article/best-power-meters-42508/

My stages has been reliable and consistent. I don't race, but I do ride every day and log about 6K miles per year. I have the shimano 105 left side crank. Battery life is decent.

FTP Power, A = 360w - 380w, B 300-330w, C 250w - 280w assume top 10 finisher , 70-75kg

Left side crank arm only

The basic Garmin power meter comes with only the left pedal, with the right pedal available as an upgrade kit. And you can of course buy them as a set.

which is a big advantage as you can swap between bikes in under 5 minutes

in england, that was a smooth road

Roads around here aren't that good either, but I thought it was funny he used the term "smooth" instead of flat and showed a road that's been destroyed by time ;)

Nope. They use them for sponsorchip reasons, has nothing to do with personal choice. Also some sky riders are using double sided prototypes of stages. Another disadvantage of left only powermeters are the much more jumping power numbers.

save your money - buy a real direct force PM

The equation given was the 'vanilla' equation for power, rather than one specifically defined in terms of rotation. If you wanted to throw 'torque' in there, you'd have to adjust everything else to make them the rotation based too. Power CAN be defined in terms of torque, however, but it's not the same as just throwing torque into the earlier equation. Power = torque x angular velocity, where angular velocity = number of rotations/time. It gives the same result though.

+Maxz torque is not the same as force and therefore should still be corrected. And as they are using a rotational based system it would be good to use the correct terms.

*Moment

+JoeHarperr torque and moment are generally interchanged but I would argue that torque suits this situation better.

If thy're going to mention torque, then they would have to bring angular velocity into it as well, otherwise they're better off sticking to the general definition of power instead of the rotational-specific one. Btw, moment is generally used where the angular velocity of the object the said force is applied to doesn't change, e.g. an object hanging off a beam creates a moment through it, whereas a rider applying force the the crank arms is actually rotating something, hence it's usually referred to as torque. Or at least that's what I've read...

Their were many things wrong with interchanging words of different meaning in this video, including that table for which it should say torque instead of force. (could have had said force 100N and moment arm 380mm). Also energy can be expressed as Nm but the distance is in the direction of the force not like torque which is the perpendicular distance from the force to the axis. for this reason is is good practice to use J for joule to avoid confusion when talking about energy.

Isn't work in joules and torque in Nm?

+NHGJLK Yes that is the proper way to express these terms to avoid confusion. Although it can be expressed as Nm which is super rare as it is misleading hence my previous response. (which could have been written much better sorry)

I think GCN should get an professional sports scientist, physicist or engineer in for these videos. There seem to always be a lot of errors in their technical presentation.