Power Meter Confusion

[huges84]

See the below thread showing everyone saying how important cooling is and how it affects their power output and heart rate. Your heart rate rises both to supply oxygen to muscles but also to cool your organs and brain. Cool your core (torso) better and you will perform better, indoors or out. Outside the cooling happens whether you want it or not. Inside, you have to make it happen. And any fan built into the trainer is not enough to match outside.

Bigger fan better numbers?

Hi All, first post, so sorry if this has been raised previously. BAsically, wondering if I get a bigger/better fan, my performance on the indoor trainer will improve? I’ve got a small rehcargable fan, which attaches to my Wattbike. It does the job, but when I’m doing a longish sweetspot effort I feel as if my HR keeps going up and I’m wondering if better cooling would help kee my heart rate under more control as it’s not working as hard to cool me down? Thoughts (and any good fan recommenati…

[ishtarbgl]

@huges84

The power numbers are calculated based on whatever crank length setting is in the device they are connected to. I would try recording power using the same device (Garmin) inside and outside, to rule out a bug somewhere using a really off crank length. Obviously 172.5 vs 175 doesn’t change power much, but maybe Rouvy or whatever else you are using is using a really bad number.

The difference in power between the spin bike and other bikes has been taken from a Garmin Edge 530, a Windows 10 PC running Zwift, an iPhone running the Rouvy App, and an iPhone running RideWithGPS. I’ve also changed from Bluetooth to ANT+. In each case they all report the same consistent power data with the spin bike being about 80 - 100 watts less at the same HR. It is very odd.

@huges84

Again, I think you need to look at your cooling situation. You keep using how the effort feels vs power to “prove” something is wrong with inside power. If you have inadequate cooling this is exactly what is expected. Your body’s self defenses make it feel really hard when you are overheating. If I ride the trainer with the fans off and a shirt on, it takes about a minute to feel too hot. In five minutes you absolutely will be too hot if riding anywhere near threshold without lots and lots of cooling and little clothing. When you ride outside you are getting 15+ mph wind over your entire body. Inside even with fans it’s only partial airflow over your body.

Oh, I’m with you 100%, cooling helps a ton, but cooling doesn’t even enter into the equation here. Let me explain. I really don’t need these 1-hour rides to prove to myself something is wrong with the power meter pedals when they are on the spin bike. This is because the wattage feels significantly different within the first 30 seconds of the ride. Cooling doesn’t even have a chance to offer a benefit.

If I jump on the spin bike and dial it up to 200 watts immediately, I’ve got about maybe 3 - 5 minutes that I can hold it before having to back it off. If I jump on my recumbent or my Son’s MTB and immediately push it to 200 watts, I can hold it all day.

As you can see, the difference isn’t gradual at all. The spin bike is simply much more difficult at 100, 150, 200 watts, etc. when compared to other bikes outdoors. I’m at a loss what to attribute it to.

[huges84]

If the difference is truly there in the first 30 seconds when starting from resting heart rate, and you have data telling you that, then I agree is unlikely to be cooling.

But your comments keep mentioning 200 watts and 5 minutes, which if that is anywhere near threshold, is plenty of time for cooling to be a major factor.

[ishtarbgl]

I know, it is only confusing because it is. Trust me, no one is more confused than me.

I know it is hard for anyone to really get a feel for what I’m seeing and feeling without being on the bike, but yes, I can feel the difference right away. Simply put, 200 watts on the spin bike just doesn’t feel anywhere near the same as it does on other bikes and I don’t know why.