Cycling power: how many watts does an average person pull? (Page 2)

that's pretty cool, so you'll be Cat 2 in like a month then?

Do most of you guys that have power taps
a) build the wheel yourself around the hub >> ordered my 1st from wheelbuilder.com and got it laced on a DT swiss wheel and the 2nd from FastSplits and got it laced on a Hed Jet 90
b) do you race that wheel or use the power tap only in training >> both and I race with a disc cover from wheelbuilder.com
c) find that it maintains it's accuracy over the years >> the PT Pro I've had for over 3 +/- years now and so far so good
d) how come saris is pretty much the only company to make power meters. I started to look at the iBike thing but reviews are pretty mixed. I still can't figure out exactly how it gets power. >> saris makes the power tap but there are other power meters. SRM is the leader (and most expensive) usually knownn as the standard in power meters, saris has come a long way and now is a close second especially with the new ANT+ feature and you can pair your PM with a garmin GPS. Also with the new wireless options you can get a wired version for like 600.00 which is a great deal for that system. Other options like the quarq is a new technology which measures power on the crank (similar to SRM) but still is a new tool with interesting features; however I am hesitant to consider until it has more tan a few years on the market.

Ergomo was another competitor using a system measuring at the bottom bracket IIRC but after a few years I think it went out of business or at least stop selling/supporting the product in the US. (maybe some ergomo users can chime in). The iBike doesn't directly measures power but calculates it using diffrent data input. It has nice features but some considerable down sides. The polar is another inexpensive option and while it is a bit of a pain to install and the power readings tend to be over stated, it is a good tool.

so if you know your speed and you know your weight, can you then get an "approximate" value for watts? most all of my races in florida are relatively flat, would that help in getting a ballpark figure?

Jorge,
What is the time they have based the numbers in the FT column on?  Is this the 20-minute test you use in your cycling program?  By the way, I have been using your program and feel like it has already been beneficial to me and I just got to the second test.  However, looking over the chart, I can't help but conclude that, uh, well, ...I really suck!  Do you have some sort of age corrected chart us older, over 50 dudes can use?

Thanks for the program you were gracious enough to make available.

Greg

Not really. Your position is going to have a HUGE effect on your speed for a particular wattage, especially on a flat course, where your weight has less impact. You might be pushing 200 watts to go 20 mph while the guy next to you with a better position may be pushing 10-20 watts or more less.

More importantly, why would you care about what your power was after the fact? If you don't have a power meter for daily use in training, estimating your wattage for a particular ride is useless. Think of it this way: if you didn't have a heart rate monitor, would it do you any good to know that your average heart rate during the bike at your last Olympic was 165 bpm? What good is that fact as a single data point? There's no reference point and no way to use that information to inform your future training.

It is based on actual FTP which usually equates to the power one can generate over a 40K time trial or roughly 60 min. The table was compiled by Andre Coggan and no they don't offer an adjusted one by Age, however I am assuming FTP for master folks even though power will drop as we age, the difference might not be as big as one would expect given adequate training.

Also one thing to remember is that those tables are based on pure cyclists hence they will have higher w/Kg than triathletes because that's their focus while we also have to focus on increasing pace for swim and run. So even if your w/Kg seems low when using those tables (and they are useful by the way), remember triathletes will gravitate towards a lower number to begin with. What matters really is how fast that power will enable you to go after swimming and before running. IMO for male triathletes relatively new to the sport (less than a few years training) a solid goal to shoot for w/Kg could start around 3.5 + w/Kg (3+ k/Kg for females). The good news is that less trained individuals while might exhibit lower w/Kg, with consistent training the gains they could experience will come relatively faster and in greater increases with consistent/adequate training

Side bar question...

Would a computrainer, if calibrated well, give you decent power numbers?  I might be able to borrow one for a bit.

yes. I have one and use the PT as well sometimes and the numbers are rather close to each other if calibrated properly.

Yes, a computrainer is a power meter with a computer/pc interface. I have both computrainer and power tap and the watts a general within 5 of each other.

thanks guys...

Another question (but I can already guess the answer is 'no').

Can you use this and work backwards into watts?  I may be lucky, but I have been surprised to find that this works within 5%-10% of my race results.  Ranging from Sprints to my Ironman...

I used the TT results and my open 5k to esitmate finish times, but they also throw in wattage.  It seems a little high because it says I pushed over 400 watts for my olys and close to 500 for my sprint (but 180 for my IM sounds about right, actually).  I do ok on the bike now, but not blazing.  However, I AM a big boy at 235 lbs...  Maybe getting that weight going that fast needs some power.

Edited by Aikidoman 2009-04-15 5:21 PM

Jorge,
Thanks for the response.  I haven't done a 60-minute test, but I am at about 200 watts FT on your 20-minute test described in your cycling program and that puts me at 2.94 w/kg.  I just started cycling from being a couch potato just over a year ago and 52 years old, so I am not too disappointed, but I have a long way to go....

Greg

 

Thats because you can coast on the open road. You can't on a computrainer/TACX

I disagree. I've always found that wattage on the trainer just seems harder than the exact same wattage on the road.

true and part of the reason is because indoor trainer's flywheel are usually small and not heavy enough to provide that inertia to generate the same rolling resistance that we experience when riding outdoors hence it is usually a bit harder to produce the same power indoors or to put it in another way; it is usually easier to produce a bit more power riding outdoors. Some trainers are now offering their models with bigger flywheels and even selling extra weight, OTOH systems like the computrainer that regulates the tension tend to replicate a bit closer the feel for outdoors riding.

If your power is 'x' indoors, in general it will be a bit higher outdoors

Jorge,

this is purely an educated guess, but my thoughts on the diff in the FTP vs 20 min power would be:

1) this is probably the largest one for me, i come from a rowing background and am very used to putting out near max effort for 6-25 min. so a 20 min test is nothing new at all for me

2) i dont have a lot of longer training under my belt

3) for me doing longer tests mentally is not something i am great at right now.

i have no idea on 5 min power

well, i dont really care about my power number per se, but when others are throwing around their wattage output, i would just like to have a figure in my head that i can use to see how im stacking up against others. i've averaged 23.3 and 23.7 in my 2 races thus far and i weigh 220 so im assuming that i have to put out some pretty good watts to keep up with my training partner who weighs 50 pounds less than i do. plus, numbers make me happy.

by the way dennis, that was one h$ll of a paint job you did on your bike/helmet. did you post any finalized pics of it yet?

Edited by JonCT 2009-04-15 11:02 PM

No final pics quite yet. Just waiting on new tires to get here so I can build her up. I'm stripping down my current ride, so I don't want to start until I have everything in place. Not sure when the tires will get here. I ordered them last week, but they're coming from Europe.

If you're talking only about trainer-based power systems like the CT, I could see this. The wording of your response makes it seem more general for all power meters, though, and I can't see how that could be true. My PT is measuring the power at the rear hub. Any interaction between systems 'downstream' from it (tire/drum, drum/flywheel, etc) aren't going to affect that measurement in the least. Likewise, if I was using a BB-based system like an SRM, the efficiency of the drivetrain would have no impact on my power measurement. My chain could be clean as a whistle or covered with crap, it wouldn't have any impact on the power I'm applying to the pedals. Sure, it would impact the power getting to the hub and therefore the wheel, but that's of no concern when I'm training as long as my legs are doing the work I need them to do.

Nope, I am talking about most power meters. This is been discussed on the power group and last year we also discussed on a training seminar with Philip Skiba. I have a CT, PT and used to have a Polar and always experienced the same, others in the group used SRM or ergomo and reported the same.  

The point is that athletes training on trainers with smaller flywheels usually report having a bit of trouble generating as much power as outside or have to work a bit harder while those with bigger fly-wheels the effort seems to even out. BTW, I am not into physics so I can't say the precise reason as to why that is, I do know that usually athletes training with power indoors/outdoors usually report the same experience.

PS. I used to have a CycleOps Fluid trainer with a small fly-wheel and that was the most challenging to replicate the same power indoors vs outdoors, then I changed to a Kurt kinetic with bigger fly wheel and it was 'easier'; I now have the CT and it is pretty even. FYI - when riding in/outdoors I always pump my tires to the same PSI and shoot to replicate the same resistance (same number of turns on the knob) before on the fluid trainers, now I calibrate the CT every session.

So what do people think about the iBike stuff as a cheap way to get into power? Waste of money or good entry point?

For bottom bracket systems, do they work with any bottom bracket or do you have to get a special bottom bracket? How are bottom bracket systems compared to the powertap?

I personally think the ibike is crap based on what I've heard/read and the way it takes measurements.  But that is just my opinion on it as I have never actually used it.  The premise behind it doesn't make sense for me (accelerometer).

Ah, I thought it measured wind and other "resistive" forces and the backed out power.

Another dumb question: I see that they made (still make?) wired versions of the powertap. How exactly is it wired if the wheel/hub are spinning?

It does.



The wire runs from the computer mount to a sensor near the hub, much like a typical cycle computer.  There is no wire directly into the hub.