Barbinator

Good morning,

This summer I started cycling again and surprisingly -at least for me- at the same level of the time I left. Now that I am in the city and I can't go out, I'm keeping in form in my gym doing at least 40 to 60 minutes of stationary bike. Even more surprisingly is that I can only keep my 40-minute rythm at an intensity between 130 to 150 watts. This summer I climbed a lot of hills with my mountain bike (rest in peace ) and long mountain passes with no more problems. Why do I say this? Because (I'm almost 170 lbs) 150 watts at a speed of 11 mph is the power I need to climb a road of a 3% gradient. Obviously this seems to be ridiculous!

Have you ever had the same problem? It's my problem or stationary bikes usually display low powers? Is there any equivalence between stationary bikes and road bikes? I'm between deceived and depressed

Leebo

No comparison between spinning and biking. Might have better luck on the road forum.

Barbinator

If so, please move it to that forum.

I know it is not the same but it has really surprised me and I'm looking for an equivalence or for someone who has suffered it. 150 watts and struggling when recently I did one important hillclimb here with not that effort. I can not explain that.

andr0id

If the gym bike is really measuring watts and not guessing them, then yes, it will certainly be equivalent.

130 - 150 watts average for 40 minutes seems pretty reasonable for an average MTB rider.

If I ride an hour ride at 21mph on the road, that will be right around 200 watts average. (Measured with a PowerTap.)

Can you ride anywhere near 20mph on the road?

How did you figure your hill climb watts? Did you use a real power meter system (something that measures power at the wheel, crank or pedals) or just a cycle computer that makes up a number?

Barbinator

What I've calculated these days is that the amount of calories burned is not so accurate but can be used in order to have a number in mind. But not for much more. I supose the bike has a magnetic tool inside to -based on your rpm's and the intensity you selected- calculate or convert it into watts. (That's what I supose).

Today the average was somewhere near the 130-140s because yesterday was my leg day and probably I was a little bit less fresh. In a good day I would probably hit the 140s or 150s with no problem. In fact, one day I did 170 but taking into account that I started sprinting at 210-230, then 100-110, and the last five minutes 150-160.

I measured my watts in a tool I had, that is not so far from the data that one friend collects. Maybe it has an error of 10 to 20 watts, but it is nothing compared to the results I got today. If I had had an average of 160 or 170 instead of 140 or 150 the surprise would have been the same.

Assuming that you are talking about a flat road, I have not measured my speed yet because I have not had the chance: almost all the roads I've cycled in are not flat or are so rocky that you can't put your bicycle at a 20 or 30 mph speed without having an accident, but in this stationary bicycle one week ago I did 1 hour at a rythm of a little bit more than 25 mph without getting tired (and the panel said I was producing 75 watts) and a peak of 30-something at 150 rpm (80-something watts), but not the 200 you say, so this 25 mph in a stationary doesn't mean anything I guess.

Barbinator

Well, I tried today. I cycled these days and today was my leg day, so my legs were not too fresh.

I did 20 minutes at a rythm of 119 watts and then another 20 at a rythm of 121 watts. I was not doing my best, so then I adjusted the seat because I thought it was too low for me and my quads were getting exhausted too soon and in the next 20 minutes I was going to try my best. Then my legs started working better and getting less tired. I did 20 minutes at a rythm of 140 watts. But I couldn't do so much more. The last minute I did a sprint of a little bit more than 200 watts but noticing that the bike's resistance was way too high.

After today, I suspect that these stationary bikes are probably displaying a number a little bit under the reality. But I don't know if it's only my thought or it's true and there is some error in the measurement. I'm so very confused now, even more than days ago when I started the post.

RIP Chainrings

Watts is watts, nothing more than joules/second. Not accurate probs. It would certainly feel different. On the road a good chunk of you watts goes toward winds, rolling resistance, and spikes during acceleration. Wattage is also proportional to the rpm. Though the watts aren't translatable per se, and will feel different, as long as your threshold wattage on the gym bike goes up it will too on the road

Barbinator

Yes, that is something I've noticed. As I started training this summer again with my mountain bike I improved a lot and, since I do stationary bike, I have raised in almost 10 watts my highest register.

I talked this afternoon to a cyclist that was in the gym (he has been for more than two hours, almost three, keeping a rythm of 180 to 190 watts and as I heard -because he has participed in some competitions- he is between cat. 3 and 4 really, and he said to me that this bikes have a little error that he has not measured but he knows they probably have, maybe from 10 to 15 % he said.

I don't know if this is too much error for a machine and he probably exaggerates, but it's the first equivalence I've heard. One friend -cat. 4- told me yesterday that he has calculated that loses between a 7 and a 12% of watts in his rollers (he says that he can do averages of 250W in the road but can't hit with the same effort the 220W in his rollers), so maybe it happens the same to the stationary bikes.

This is the closest explanation I have got these days. Still don't know if accurate.

CaptKelly

if anything I've found stationary bikes overreport wattage.

rdtindsm

I use a commercial quality Precor bike at my fitness club. While there seem to be some idiosyncrasies in its measurements, I find that the speed displayed to compare closely to my road output. Back in the day, I was a pretty good time trialist with championship medals in several different states and even at the masters' nationals, so I have a pretty good sense of pace. My daily training rides tend to be close to time trial efforts. I am finding that my speeds on the indoor bike are comparable to my outdoor speeds, about 18 mph. I am old and decrepit, a mere shadow of my former self.

I do find that my cadence inside is about 95, probably 10 rpm higher than outside.

Short answer - it will depend on the trainer and measuring system. All you can ask for is consistency.

The club has a spinner bike; I don't use it because I can't calibrate the effort.

Barbinator

The most hilarious is that there are some brands of stationary bikes and every model displays a different number so I don't know if my average is 130, 150 or 160. There are not two stationary bikes that tell the same.


And this is my question (maybe you will find it hilarious and will make no sense): can the difference between stationary and rollers or stationary and road bicycles be the rollout of the bicycle or the resistance of the first ones? I mean, in a stationary we have a bike with no rollouts to be changed, only with a resistance level that can be raised or lowered, and in rollers and a road bicycle we have no resistance but real slopes and rollouts that we change in order to overpass it with less effort.

Precor stationary bikes are the best. In my gym all the machines are Precor, excepting the stationary bikes (we have a Technogym one instead), that's the disadvantage. As I ask the people, some say they underreport wattage by a 10% of error, other say that the error they measured between rollers and outdoor was from 7 to 12% and some others say that they think -as CaptKelly said- some machines overreport it.

As I only had one power meter and was not mine, I can't tell you with accuracy; my guess is that these models underreport the wattage but can't tell you. What it's true is that I've noticed that is for me harder to mantain a 60 rpm rythm indoor than a 70-75 outdoor. Wattage can be correct but not the resistance, I found very hard to move it.

RIP Chainrings

I would think that to constant high resistance would drain the rider to put out fewer watts than would a road bike. If one lowers the resistance and spins faster one can do the same watts or more and it should carry over to higher cadence on the bike. Additionally, it's not that hard to do 250 watts for some time on a bike depending on carb levels, but surely probably way harder on a precor, so I'd imagine it isn't reading out the full power. Maybe it's part of the training design

Barbinator

Must be that. Today I've done an average of almost 170 watts (I was really fresh) keeping a cadence of 80 rpm in the eight level of resistance (155 watt) and a cadence of 72-74 in the nineth and tenth ones (180 watt), pretty hard.

I've kept spinning at a high level all the time, because if you are cycling in this stationary at 80 rpms, you get less tired than cycling at 60, do not know why, maybe because of the difficulty, as you say, to maintain the same resistance; if you don't cycle fast, you won't be able to push down the pedals.

I got very tired in the last minutes at 170 watt (68 rpms) but then I started doing my best at 76-80 and extrangely I got less tired and in a higher level of 190 with no problem. I did also in the last minute of sprint of 200 watts.

My average speed was 23.7 kmph (14.8 mph) in the first 20 minutes and 23.9 kmph in the second ones. But I can't find an equivalence with the real life because this doesn't work with slopes as other machines do. My thoughts are that these machines must be underreporting my stats (one friend did 110 and struggling). What I am trying to find is the percentage of error they have.

Barbinator

Hello everybody.

This week the gym crew announced that they had bought new spinning bicycles in order to create a new activity: Virtual Bike. In this new activity, the teacher put us a video of a monitored cycling class in which another teacher showed us a video of a hillclimb profile and taught us how to climb, new techniques, what gear we should put, new movements... Pretty amazing.

Well, these bikes (brand BH, model Hi-Power) had an ergometer connected by a cable to the wheel of the bicycle (which had 16 different gears). Well, today I ran at a pace of 200 watts with no problem (they say these bikes have an error between 2 and 3 %), most of the time I was between 209 and 217 but then I lowered my pace to 186-195 because I had some muscular problems derivated from the training of yesterday. My highest average (and struggling very much) -since today- in the stationary bike I mentioned in the first message had been something like 182-186. So maybe I was not that wrong when I said that the error could have probably been the 10%. So the average was 200-205. I found today that in the 9th gear (out of 15) I could put 170 watts without being so much tired. In the 10th I could mantain 190 and in the 11th I was very tired trying to keep the 220, sweating like a pig. In the stationary the biggest struggle was to beat the big resistance; in this spinning was to not to get tired. Even in the last minutes I did an 'attack' (in the other stationary I couldn't because the pedals did not allow me to stand up and the bike fell down) of 350 watts with no problem. I ended very happy because of this.

So I can now say that the stationary had an error of a 10% and that I'm a very poor cyclist who can produce in 20 minutes only 3,X watts per kilogram