For those of you that have used a PowerTap;
How much of a difference in watts do you notice (if any) between the trainer and on the road?
Is there anything in setting the bike up on the trainer that could skew the actual watts reading?
The big difference between the trainer and the road is the wind, or lack thereof, on the trainer. Some people see a 5% drop in wattage, some put out the same power, totally depends on the rider. The better the ventilation you can get on the trainer, the close it’ll feel to road.
There really isn’t anything you can do with the trainer to skew the watts since its a measure of power output from your legs through the drive train, to the hub. The trainer is outside of the equation.
For me it is the same/same. It all hurts. Fans, etc. do play into it, but in the end power at the hub is power at the hub.
That’s what I assumed. That power at the hub could not be effected by the set up. The only difference I figured to be noticed would be speed because of wind, hills, etc.
Thanks!
There will likely be 10 posters getting on here saying your watts will drop by like 100- not true.
If anything, the cadence I am comfortable at changes by like 5rpm/min on the trainer. With cooling/hydration/motivation, watts are the same. Hr is typically similar also, not that it matters too much.
-Physiojoe
Power is power is power.
There are two things about riding indoors that can affect your power.
Cooling and being a big sissy.
I think the scenery, moving air, chance to occasionally recover makes riding outside at the same power feel much easier.
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There is no question that most trainers have a significantly lower inertial load than what you experience riding outside so it will ‘feel’ different. Personally, when I start riding the trainer my knees seem to ache and my power for a given PE is lower. After 5 or 6 sessions that ache goes away and it gets easier to maintain power similar to outdoor.
It’s also common for riders to be able to put out more power uphill than on the flats because if ‘feels’ different.
How much of a difference in watts do you notice (if any) between the trainer and on the road?
If you don’t manually zero it? Possibly a lot.
Is there anything in setting the bike up on the trainer that could skew the actual watts reading?
Yes. Not manually zeroing it.
I agree that PE is usually higher the first few sessions after not using the trainer for a while.
As long as I have proper cooling while on it, I don’t feel I lose anything.
I did not know this either. Can you please tell me how to zero it? I can’t seem to find much on a “stomp test” if that’s the test to do. I have a powertap pro+ with a garmin 500.
Thanks for yor help.
Marty
I’m no expert but I suspect that it depends on how much you tighten the load generator onto the tire. Just beyond the point where you get no slippage when holding the load generator and attempting to turn the wheel - not much difference in watts needed to generate the speed you’d expect (and therefore the RPE you’d expect) on the road. Set it so that it is very tight, and you’ll find it hard to simulate the road feeling and your RPE for a given speed will be higher.
My experience has been more watts required on CompuTrainer than on the road. I compared a CT real course video ride to a real world power file (both using the PT data). The data compared was the first 60Km of the IMC course and took about 2 hrs. Real world during IMC I averaged about 125 watts; on the CT my Avg Power was about 180 watts.
My FTP is 7 watts higher on road. So pretty close. There is a not a flat road to be found where I live. My test route is as flat as I can find but’s still has a lot of false flat and some bumps that cause a few spikes in power that account for a couple watts. It’s also easier to maintain mental focus on the road in my opinion. My heart rate is usually a few beats higher indoors but that is most like just the simple issue of cooling. I do think trainers make a difference as well. My Kinetic has a much heavier flywheel than my old cyclops. Maybe it’s just the smoother feel, I can’t say for sure because I have not tested on the cyclops.
There is a difference. It’s not like 100 watts or something like that, but I have found that average power indoors is around ten-twenty watts lower. The difference in normalized power can be significantly more outside, especially if you are doing a hard group ride or if you are on a course with lots of steep kickers.
There are a variety of physical (i.e. inertia) and physiological (i.e. cooling inside v. outside) reasons. I think that there are also mental reasons related to moving quickly through space as opposed to staring at your stem.
On another thread someone suggested that you have an “indoor baseline.” That is, you should compare your indoor numbers to your indoor numbers, and use that to track your improvement. I totally agree.
I did not know this either. Can you please tell me how to zero it? I can’t seem to find much on a “stomp test” if that’s the test to do. I have a powertap pro+ with a garmin 500.
Thanks for yor help.
Marty
I don’t have a Garmin 500 so I don’t know the exact procedure. You’ll have to check your manual. The issue is that when set on “torque autozero” the autozero is supposed to occur when coasting – but on a trainer most people don’t coast so there’s no chance for an autozero to occur. So to get the best results you’ll want to manually zero.
We had a discussion almost two years ago about an interesting case where someone claimed that his power had improved tremendously from the use of PowerCranks – but when we examined the data it turned out to be a case where he didn’t manually re-zero his power meter. As an aside, this was on top of other cases where someone claimed that a power meter file would prove that PowerCranks improved power but when the file was examined it turned out not to be so. Funny how that happens.
Just to repeat what everyone else has said…
If you’re a high torque rider, get yourself a trainer with a lot of inertia. Kurt Kinetic Road Machine with the Pro Resistance fly wheel gives you a 60 second cost down from 20 or 30 mph (i forget which one). It’s expensive though.
Get a BIG fan. Not some wall mart fan. It does not matter if your room is cool. You want evaporative cooling.
Here’s an 20 inch air king http://www.amazon.com/Air-King-20-Inch-Pivoting-9220/dp/B0007Q3RHK/ref=sr_1_2?ie=UTF8&qid=1320772759&sr=8-2 Put that thing on a desk right next to you on high. Yes, it’s loud. Yes, your eyes will dry out (wear some glasses), but it will be harder to overheat.
Last, get some motivation. That could be music, a movie, structured workouts, a friend, ect. Have a plan before you get on the trainer and a goal. Don’t get off until you complete that goal.