# Tacx Satori watts



## oivind_h (Jun 29, 2007)

Do anyone know how accurate these measurments are.
According to this I can hold 350 watts for an hour, and I`m not well trained!


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## Kerry Irons (Feb 25, 2002)

*You already know*



oivind_h said:


> Do anyone know how accurate these measurments are.
> According to this I can hold 350 watts for an hour, and I`m not well trained!


It sounds like you already have your answer. What is the mechanism they use for estimating power? If it doesn't involve some sort of strain gauge, then they're really just guessing. And history would show that when makers of exercise equipment guess on watts/calories, they tend to guess 30% high, or more.


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## ilan (Nov 27, 2006)

I assume that this is power versus speed. First of all, this graph seems to be contradicted by the Tacx website, which states here http://www.tacx.com/producten.php?language=EN&ttop=Cycletrainers&lvlMain=16&lvlSub=57&lvlSubSub=81
that you can generate 400W at 27kph, but the graph seems to indicate that you can actually generate 450W at about 25kph (assuming they were trying to give the maximum wattage at lowest speed). 

Anyway, it is easy to measure these wattages using any kind of reliable power meter. However, the actual wattage you observe should be highly dependent on the tire you use, how much it is inflated, and how tightly it rests on the roller. In fact, I wonder if the wattage will change during a ride, assuming that the tire heats up and its pressure rises. 

-ilan


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## ilan (Nov 27, 2006)

ilan said:


> I assume that this is power versus speed. First of all, this graph seems to be contradicted by the Tacx website, which states here http://www.tacx.com/producten.php?language=EN&ttop=Cycletrainers&lvlMain=16&lvlSub=57&lvlSubSub=81
> that you can generate 400W at 27kph, but the graph seems to indicate that you can actually generate 450W at about 25kph (assuming they were trying to give the maximum wattage at lowest speed).
> 
> Anyway, it is easy to measure these wattages using any kind of reliable power meter. However, the actual wattage you observe should be highly dependent on the tire you use, how much it is inflated, and how tightly it rests on the roller. In fact, I wonder if the wattage will change during a ride, assuming that the tire heats up and its pressure rises.
> ...


Well, I bought the Satori trainer and did my first hard workout today. I measured 300 Watts going 34 kph at level 7 resistance (the roller was pressed quite hard on the tire). That's lower than the chart, but seems somewhat consistent with their claim of 450W at 25kph at level 10, which I may check out some time later, when I am in an even more masochistic mood. In any case, the trainer has good enough resistance for my purposes (I had a hard time generating over 250W on my old fluid trainer). I measured power with my PowerTap meter.

By the way, are you supposed to put the rubber spacers on the inside or the outside of the trainer faces? The instructions were insufficient to decide this. 

-ilan


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## oivind_h (Jun 29, 2007)

I took a look at my trainer and I couldn`t see any rubber spacers.
It`s a long time since i put it together so I don`t remember. Maybe I unscrewe it and take a look.

Last winter i took a test and tried to ride as hard as I could for an hour and managed 
36 km at level 5.
According to the graph that would be about 330-350w.
I think that is a bit strange since I had only trained seriously on my bike for 2 months
and I`ve heard that pros can manage to get around 500w!!


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## ilan (Nov 27, 2006)

oivind_h said:


> I took a look at my trainer and I couldn`t see any rubber spacers.
> It`s a long time since i put it together so I don`t remember. Maybe I unscrewe it and take a look.
> 
> Last winter i took a test and tried to ride as hard as I could for an hour and managed
> ...


The rubber spacers are part of the things you put in to hold the resistance unit. I think they go outside so that the plastic part doesn't contact the metal trainer directly. Tacx assumes one would be able to figure this out.

I can check what 36kph at level 5 corresponds to. It is probably about 250W depending on how hard you put the roller on the tire, assuming that at level 7 it is about 300W, as I measured last week.

Absolute wattage numbers are important, but it is also important to know your wattage/your weight. In particular, you threshold wattage (highest you can maintain for an hour)/(weight in kg). The best riders are about 5, and beginner amateur racer slightly over 3. So the number 300W might be very good, or just average, depending on your weight. 

-ilan


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## oivind_h (Jun 29, 2007)

If 250 watts is right my power/wheight ratio is 3.5.
Thats not bad for one that has never trained for any endurance sport. 
Let me know when you have figured it out.
Gonna give it another try when my knees is healed and see if I have improved.


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## FredBlack (Sep 6, 2006)

I have the same trainer. As I do most of my training on the 4 and 5 resistances, I would greatly appreciate it if you could test the 300W, 350W, 400W, 450W reference points at these resistances. By the way, what tyre do you use, and at what pressure?

I use the Continental Ultra Sport Hometrainer Tyre inflated to 120psi





ilan said:


> Well, I bought the Satori trainer and did my first hard workout today. I measured 300 Watts going 34 kph at level 7 resistance (the roller was pressed quite hard on the tire). That's lower than the chart, but seems somewhat consistent with their claim of 450W at 25kph at level 10, which I may check out some time later, when I am in an even more masochistic mood. In any case, the trainer has good enough resistance for my purposes (I had a hard time generating over 250W on my old fluid trainer). I measured power with my PowerTap meter.
> 
> By the way, are you supposed to put the rubber spacers on the inside or the outside of the trainer faces? The instructions were insufficient to decide this.
> 
> -ilan


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## ilan (Nov 27, 2006)

FredBlack said:


> I have the same trainer. As I do most of my training on the 4 and 5 resistances, I would greatly appreciate it if you could test the 300W, 350W, 400W, 450W reference points at these resistances. By the way, what tyre do you use, and at what pressure?
> 
> I use the Continental Ultra Sport Hometrainer Tyre inflated to 120psi



Well, I'm not quite into the full time trainer season yet  When I get a lot of hours in, I'll be able to answer some of these questions. However, it seems pretty clear that pressure on the roller is going to make a lot of difference, maybe 40W, so the absolute numbers will only be very approximate at best. Also, the roller memory is not very good since the knob is totally loose when not engaged so tends to turn a bit, so my numbers may not even be consistent from one workout to another. However, I did notice that going up one level at the same speed seemed to increase the wattage by about 20, at least at low speed (25kph) and low resistance. That may give more reliable relative numbers.

I'm still riding my road continental Force (or is it Attack), which I won't enjoy destroying on the trainer. I also inflate it at 120. 

-ilan


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## peanutbotter (Sep 26, 2007)

"By the way, are you supposed to put the rubber spacers on the inside or the outside of the trainer faces? The instructions were insufficient to decide this." [Originally Posted by ilan]

If it is the rubber rings "G" (item: T1456.01) you are referring to, they go on the inside. They fit on the steel rod of the handle "H" (item: T1852.22). See illustration 6 and 7 of the instructions for further clues. Hope that helps. Regards, Paul


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