Accuracy of Gym bikes?

fezzy

I have been riding the gym bike that has wattage now for about two weeks in order to get ready for next year. I did the FTP test as described in Training and Racing with Power and came up with an estimated 210. I also have ordered a Powertap so I should be able to answer the question myself in a few weeks once the wheel is built up, but I wanted to know if anyone here had experience going from a gym trainer to a power measuring device on bike and if so how did they compare? I did the 5 minutes all out and averaged about 260. I couldn't imagine pushing that for 20 minutes. I thought I was going to puke afterwards.

My racing weight is around 70Kg, but I am currently up to about 73. I have been riding fairly steady since April in the 7-10 hours a week range, although they did dip down for October and about half of November, so I am a pretty new rider. Cat 5, did about 4 races last year and plan to race about 15-20 next year, mostly crits with some road races here and there.

Rob Havemeyer

IMO I think there is more than likely variance in gym stationary bikes poweroutput. And I'm not sure how close they are compared to a PT. Unfortunately I have not done any comparisions. I know that the few that I've used seemed to have maxed out with regards to resistance and watts. The best thing you can you is to get your PT laced up and start using it with CyclingPeaks. Do you have a trainer ?

fezzy

I do have a trainer, and I can't wait to get going with it. I have purchased CyclingPeaks and am about half way through Training and Racing with Power, not to mention all the reading I have been doing on here.

Im really just hoping that 300 watts isn't as hard as I think it is. But I know I need to go a lot faster in order to race the way I want to race next year.

Rob Havemeyer

It sounds like your on the right track getting cycling peaks as well as reading Racing & Training with Power. As you've read when you get your powertap you'll want to do some baseline tests. 1min, 5min, 20min etc. in order to have a good starting reference point. 300watts for any newbie (including myself) is going to hurt for longer than 5-10min.

I've only been training with power for 6 weeks now but have seen some pretty big gains on Nov 1st I had done a 20min all out effort @ 247watts plus had two other 20min efforts to verify that data 246 & 248 watts within a week of each other. So feeling OK but not thrilled with the number.

Since then things have changed a bit. 2 weeks ago I pulled a 260watts for 20min. Then this past Sat (30days since the first test) I pulled off a 281watts !!! 13.7% in 30days!

P.S. How did you do in you first few races ? Were they Crits or Road races ?

fezzy

I am very interested to seeing how my numbers from the gym will match up to the PowerTap numbers. I am hoping it will be ready this coming weekend, but more likely it will be next week. Question, what do you weight? Those numbers sound pretty good to me, at a lowly 210, and only 70Kg (racing weight). Are the numbers you mentioned flat out 20 minute efforts, or 95% of actual 20 minute efforts as described in Training and Racing with Power?

My results last year in racing were not so good. I did 3 crits, a road race and a century. I was shelled in the road race and the first crit almost immediately. In the second crit, I stayed with the main pack until the end and finished I think around 10th out of 25 or so in a 4/5 field. The other crit had 10 guys off the front and I stayed with the rest of the group, but there was no way we were ever going to reel the lead group in. My overall goal is to get fit enough to be able to have a strategy other than dont die.

Rob Havemeyer

Those were my actual avg's for the 20min. My current weight is 75kg and my in season weight is around 72kg. This was my first season racing 14 in ttl. I felt overall pretty good about it. My first few races I went out on a break myself, blew up and got dropped. Rookie move. I had a number of top 5 finishes in the second 1/2 of the season. With my first win in Sept. I raced with the PT for the first time last weekend..Brrrr it was cold in NY. Great Data though...Now I know how long the final sprint is. How much power I had then lost during the final sprint. Having the PT will really let you see what is happening in your races and more importantly what you need to work on. Obviously everything is event dependent. I don't know where you live or what your typical training rides are like.

But I was suprised when I got my PT to see that on a typical morning ride how much I was not putting out any power. This was due to traffic lights (ohh boy 20 traffic lights in a 1 hr ride will kill ya) intersections other cars etc.
The first time I looked at the data I realized that the longest amount of time I would pedal w/o stopping/coasting was no more than 4min!! Due to the traffic lights etc. And my power less than <140Watts (or recovery range) on a typical training was close to 30%.!!

It makes sense to me now since I've been inside on a trainer for the first time I'm making bigger gains. Its been a difficult transition from only 4min of constant power to 2hrs+ on the trainer but so far it has paid off.

Sillyoldtwit

After nearly 2 years of using the gym trainer, I recently purchased a CompuTrainer, and so far I have only cruised on it doing 250Watts intervals. The reason for sticking with a low wattage was so I could do a fairly accurate comparison with the gym trainer where 250 watts was fairly easy until I (as usual) overheated in the gym atmosphere. I would say my gym trainer is/was fairly accurate vis-a-vis weighing up the perceived effort.
And 300 watt 20 minute intervals for most of us normal beings is by no means an easilly attainable feat. If you read the beginning of the "It's killing me " thread, you will see that RapDaddyo said, many of his club memebers would be happy with a 250 Watt FTP!
To-date, my best has been 1x10minutes @ 300watts. At the end of January I intend to test myself again ( exactly 2 years after I started serious structured training) - then all things being equal, I should be able to see if indeed the gym trainer was accurate or not.

Best of luck with reaching 300W and remember if you do, there are many who just can't and you should get down on your knees and thank your father. Tyson

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Ergoman

The odds are that your gym bike power meter isn't particularly accurate. Actually, it's a good bet that no power meter is 100% accurate although some are closer than others.

What is important is that a power meter be consistent and your gym bike probably is that unless it's one that's affected by overheating. OTOH, don't be too surprised if the gym bike power doesn't match what you read from your new PT. Again, so long as the PT is consistent and you plan your workouts using PT data and do the workouts on the PT, no problem. If you jump back and forth from the gym bike to the PT equipped bike, then there may be a big problem.

fezzy

I spent some time reading the "Its killing me" thread and found it very helpful. Your progress has been impressive. I didn't realize it had been two years since it was started.

My short term goal is to get the FTP up to 245, or 3.5 w/Kg by spring. Assuming the gym bike is reasonably accurate and I will have some improvements from not riding in the warm gym, and the fact that I am basically a new rider I hope to see solid gains for the next few months. Getting anywhere near 300 isn't even fathomable to me at this point. According to the charts, 3.5 w/Kg should make me competitive in 4/5 races, although 4 would be nice. Now I just need to learn how to race.

Sillyoldtwit

As you can imagine, when I was grinding out 140/150 watt intervals, 300 watts to me was on a different planet. However, with hard persistent work and genes willing you'll get there or even surpass 300w.
Must get back on the trainer now, I'm starting to get cold. Tyson.

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Piotr

Don't neglect thanking your mom too. She's actually the one who gave you your mitochondria.

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