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What would the approximate power be?

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What would the approximate power be?

Old 12-13-14, 06:47 PM
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Originally Posted by Doge
We disagree. If you could give us a real RPM of the spindle of the trainer and some real tire deformation then we could get power if Fluid trainers were constant - ours is not.

My point is who you are is a better power predictor than the all the other variables needed to work through to figure out the power required to turn a power trainer at a certain RPM.
"who I am" may be a predictor of my ability to generate a given level of power; it has nothing to do with the power it takes to move the crank at a certain level of resistance (in this case 53x17) at a certain rpm (in this case 88). Whether it's a machine or a human turning the pedals at that gearing/rpm has no bearing. It takes a x amount of watts to do it; it could take 342 watts for all I know, not 341, not 343. I simply asked for an approximation, i know it won't be exact or perhaps not even within 15 watts. I am well aware of the variables of tire pressure and how tightly the wheel is afixed to the resistance unit. I can't tell you what the "rpm of the spindle of the trainer" is, on rpm of the crank arm.
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Old 12-13-14, 06:51 PM
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I have a fluid trainer. I have a Power Tap. The power it takes to do the same RPM in the same gear varies based on temperature and it just varies by 50 W or so. My wife has a fluid trainer. The same RPM is different on hers.

So I guess a number way above based on the 1st data - under 300W.

Yet two guys within 5 years apart in age about the same weight and body composition that ride about the same amount - put out a closer number to each other than two fluid trainers.

Last edited by Doge; 12-13-14 at 06:57 PM.
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Old 12-13-14, 06:58 PM
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Originally Posted by Doge
Still missing my point. I have a fluid trainer. I have a Power Tap. The power it take to do the same RPM in the same gear varies. My wife has a fluid trainer. The same RPM is different on hers.
If you are using two different trainers, then sure, it very well make take a different level of power. But if you two both use the same trainer with all variables controlled for (for ex. tire pressure, how tight the wheel is afixed to the resistance unit etc.) then it should take exactly the same wattage to turn the cranks.
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Old 12-13-14, 07:02 PM
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It changes after 15 min of riding.

My son has rollers - Kreitler 3.5 inch. The power it takes to at the same RPM to warm up with 110psi is about 75W difference between his clinchers and his race silks.
How could we guess the power for your device?
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Old 12-13-14, 07:10 PM
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Originally Posted by Doge
It changes after 15 min of riding.

My son has rollers - Kreitler 3.5 inch. The power it takes to at the same RPM to warm up with 110psi is about 75W difference between his clinchers and his race silks.
How could we guess the power for your device?
Correct, but as I said, I warm it up until the viscosity of the fluid is at it's thickest before starting the 30 min. interval. By switching tires on your sons rollers, you've allowed variables to be entered into the equation. No, you can't guess the power on my particular machine. I asked for "an approximation" just to see what kind of ballpark I'm in, that's all.
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Old 12-13-14, 07:26 PM
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I'll test it for you tomorrow. Please give me gears and rpm again.
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Old 12-13-14, 07:30 PM
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Trainerroad didn't see variability in resistance with the Fluid2 as a reason not create a VirtualPower curve for it, nor for them not to put significant work in doing so in order to get it as accurate as possible.

I use a Powertap wheel on F2 and don't notice such variable power that I have to shift to maintain power over time, or shift more frequently than I would expect to hit my power zones, so I don't know what all the hubbub over the supposed variability is (unless it's between units; why that though?)

I also find that I have to get pretty deep in the cogs, like 53/13 at 80+ish rpm to do sustained 300w intervals, which is why I said the 53/19 probably isn't very high wattage. I'd guess 180-220w, but that's not based on any serious attention on my part, just a moderately WAG.
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Old 12-13-14, 09:36 PM
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53x17 @ 88 rpm:


53x19 @ 88 rpm:


I kept taking pictures that were 1 rpm off but the consistency is pretty decent. I uploaded them from the phone while I was on the bike. They're in reverse order but you can see that I was trying to take pictures for a few minutes. It was killing me as my FTP is 200-220w. To put things in perspective when I was uploading my HR was down in the 115 bpm range. These efforts were anaerobic for me.

Shot 1 of 3, 53x19 @ 89 rpm:


2 of 3, 53x19 @ 89 rpm:


3 of 3, 53x19 @ 89 rpm:
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Old 12-14-14, 01:09 AM
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Interesting, CDR. I did a Z2 ride tonight and used only 53x19, 17, & 16, with cool down in the 19, and averaged 202w for 1hr 4min @ 89 avg cadence, 18.9mph avg, and never breaking a hub-indicated 23mph. It was a steady state ride, and I don't think I shifted more than 4 times throughout, so I'd expect the consistent power results to be pretty accurate.

Trainer Profile | Hot Z2 Action! | Times and Records | Strava

That's a striking difference from your results. My F2 is many years old, maybe 8, but I don't remember. Could the fluid properties change over the years? How else to account for that variance?
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Old 12-14-14, 08:58 AM
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Originally Posted by carpediemracing
53x17 @ 88 rpm:


53x19 @ 88 rpm:


I kept taking pictures that were 1 rpm off but the consistency is pretty decent. I uploaded them from the phone while I was on the bike. They're in reverse order but you can see that I was trying to take pictures for a few minutes. It was killing me as my FTP is 200-220w. To put things in perspective when I was uploading my HR was down in the 115 bpm range. These efforts were anaerobic for me.

Shot 1 of 3, 53x19 @ 89 rpm:


2 of 3, 53x19 @ 89 rpm:


3 of 3, 53x19 @ 89 rpm:
CDM, thanks so much for taking the trouble to do that. My mph for those gearings were just like yours so I imagine my power is pretty close to what you are showing give or take a few watts. I'm pretty happy with 288 watts for 30 min. especially not having actually ridden a bike (road or mtn.) in over 4 months. Now I have a point of reference and can hopefully increase my power a little while waiting for the spring to get here.

On a side note, it looks like you have Nokon cables. How do you like em? Thanks again!
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Old 12-14-14, 09:50 AM
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Originally Posted by chaadster
Interesting, CDR. I did a Z2 ride tonight and used only 53x19, 17, & 16, with cool down in the 19, and averaged 202w for 1hr 4min @ 89 avg cadence, 18.9mph avg, and never breaking a hub-indicated 23mph. It was a steady state ride, and I don't think I shifted more than 4 times throughout, so I'd expect the consistent power results to be pretty accurate.

Trainer Profile | Hot Z2 Action! | Times and Records | Strava

That's a striking difference from your results. My F2 is many years old, maybe 8, but I don't remember. Could the fluid properties change over the years? How else to account for that variance?
You may have a bit of a leak. I have an older Fluid trainer (first gen) and I thought I was progressing really well (when I didn't have a powermeter). At some point I got on a friend's CycleOps fluid trainer and I was shocked at how hard it was. I warranteed a second CycleOps I had, an e-trainer (mine literally started to smoke, melting wires and such). I asked for just a resistance unit but they sent me a Fluid2. This is what I've been using now, and it's much harder than my prior trainer.

Other than that I'm sure tires have something to do with it. The resistance goes up exponentially on the trainer, and at 20-25 mph the changes are significant. 2 mph and change and power goes up 30%. I realize now that it would be hard to replicate the set up. For example if I reduce roller pressure I think power requirements would go down. I'll experiment a bit when I ride the next time.
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Old 12-14-14, 10:15 AM
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Originally Posted by whitemax
CDM, thanks so much for taking the trouble to do that. My mph for those gearings were just like yours so I imagine my power is pretty close to what you are showing give or take a few watts. I'm pretty happy with 288 watts for 30 min. especially not having actually ridden a bike (road or mtn.) in over 4 months. Now I have a point of reference and can hopefully increase my power a little while waiting for the spring to get here.

On a side note, it looks like you have Nokon cables. How do you like em? Thanks again!
As I mentioned in my comment above I think that my power numbers are very rough. I think that borrowing a PowerTap wheel or having a friend try a powermeter equipped bike would be the best way to "measure" your trainer. Just to give you an idea I was absolutely anaerobic hitting those numbers and I struggled to hold the camera steady because I felt like I was being asphyxiated doing the efforts. The lens also got foggy from my hands.

Nokons - I got them because I had to turn my bars a lot to get the bike in my car. I blew out Campy shifter housings within a few months, maybe 50-70 total trips. After I blew out a second set of Campy housing I decided to get a segmented housing made from solid cylinders of metal. THe Nokons fit the bill. The early versions, from the mid 2000s, had finish durability problems, but the ones now I've been using for a couple/few years and they're good.

Quick advantages:
- cable housing can't blow apart and in fact the segments basically don't wear unless they're rubbing something like your frame.
- housing doesn't compress at all, although you have to "seat" the housing initially (meaning against themselves).
- you can lengthen housing if moving cables to a different bike or if you're installing a different bar or stem.
- lighter (although it's not much)
- you can seal most of the housing (I run the liner for most of the cable so the cables aren't really exposed to moisture)
- very flexible so you can do some crazy tight turns with the housing.
- reusable (the blue I got in 2010, black in 2011, silver ones under the tape I got in 2007?).
- easy to get even lengths, just count segments. I do this for the shifter housing from the lever to the downtube.
- reparable since you can replace one segment if necessary. I have all my extra segments in a small take out container with a lid.

Disadvantages:
- cost more - typically sold for brakes only or derailleur only, so be careful if you see a good price for "a set".
- requires 1.1 mm derailleur cables (skinny)
- doesn't hold shape as well as regular housing due to the incredible flexibility of the set up.
- if you are tall or have full length housing (like internal top tube brake cable or disc brakes) then you may need to buy additional segments. I've bought 3 sets over the years and I use most of them on two shorter height bikes. Black one has full length internal brake cable housing. Both bikes are longer, 56.5 cm top tubes, so about the same as a 56-57 cm frame. If you have a 60 cm or size XL then you're realistically going to be very short on the segments.

Some thoughts on Nokons.

A picture from my set up before I dropped the clamp point by 3 cm. Note the front brake cable housing curve, which is much worse now that the tops of the bars are 3 cm lower. You can see the transition to black near the tape, and under the tape I run my very beat up silver housing. I also run the silver inside the top tube.
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Old 12-14-14, 10:19 AM
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Originally Posted by carpediemracing
You may have a bit of a leak. I have an older Fluid trainer (first gen) and I thought I was progressing really well (when I didn't have a powermeter). At some point I got on a friend's CycleOps fluid trainer and I was shocked at how hard it was. I warranteed a second CycleOps I had, an e-trainer (mine literally started to smoke, melting wires and such). I asked for just a resistance unit but they sent me a Fluid2. This is what I've been using now, and it's much harder than my prior trainer.

Other than that I'm sure tires have something to do with it. The resistance goes up exponentially on the trainer, and at 20-25 mph the changes are significant. 2 mph and change and power goes up 30%. I realize now that it would be hard to replicate the set up. For example if I reduce roller pressure I think power requirements would go down. I'll experiment a bit when I ride the next time.
What's interesting is that your numbers don't comport with the TrainerRoad Fluid2 power curve estimates.

According to that, you'd need to do roughly 21-22mph to hit 300w, but a 53x19 at 88rpm is well under 20mph, like 19.2mph, which does sync up with your measured results. Power, though, at 19mph, looks like it should be more in the 220w-230w range according to TrainerRoad.

What's your take on that?
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Old 12-14-14, 10:51 AM
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Yeah, I just double-checked my gear selection and warmed it up for 6 minutes, rode is steady for another 3-4 to watch the numbers, and the 53x19 at 88rpm is in the 210-220w range.

That's probably on the low side of the TR curve prediction by 10w or so, so if we take your average 10w spread range as 285-295w (which is on the high side of that same curve by 40w or so), that shows a huge swing for Fluid2, in which we must account for setup (tire psi, roller pressure, tire size). I mention the range on either side of the TR curve because the sample set used to generate it was much larger than our two!

So yes, I agree with your assessment that the OP should really get a power meter on his to generate a baseline power range, because an 80w swing is too wide to take seriously.
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Old 12-14-14, 11:01 AM
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Originally Posted by chaadster
What's interesting is that your numbers don't comport with the TrainerRoad Fluid2 power curve estimates.

According to that, you'd need to do roughly 21-22mph to hit 300w, but a 53x19 at 88rpm is well under 20mph, like 19.2mph, which does sync up with your measured results. Power, though, at 19mph, looks like it should be more in the 220w-230w range according to TrainerRoad.

What's your take on that?
No idea. I was obsessively checking slope, etc. Maybe my tires, although I don't feel like switching tires (I have the same tires across my clinchers).

I don't think it would be possible that my SRM reads that much higher than actual values, else my wattages when I'm riding outside would be ridiculously low (like crits where I avg 160-180w).
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Old 12-14-14, 11:37 AM
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Originally Posted by chaadster
Yeah, I just double-checked my gear selection and warmed it up for 6 minutes, rode is steady for another 3-4 to watch the numbers, and the 53x19 at 88rpm is in the 210-220w range.

That's probably on the low side of the TR curve prediction by 10w or so, so if we take your average 10w spread range as 285-295w (which is on the high side of that same curve by 40w or so), that shows a huge swing for Fluid2, in which we must account for setup (tire psi, roller pressure, tire size). I mention the range on either side of the TR curve because the sample set used to generate it was much larger than our two!

So yes, I agree with your assessment that the OP should really get a power meter on his to generate a baseline power range, because an 80w swing is too wide to take seriously.
Agreed, yes I should get a power meter. Thing is, I don't have one and wanted to get some kind of idea of power for this particular workout interval.
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Old 12-14-14, 11:46 AM
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Originally Posted by carpediemracing
As I mentioned in my comment above I think that my power numbers are very rough. I think that borrowing a PowerTap wheel or having a friend try a powermeter equipped bike would be the best way to "measure" your trainer. Just to give you an idea I was absolutely anaerobic hitting those numbers and I struggled to hold the camera steady because I felt like I was being asphyxiated doing the efforts. The lens also got foggy from my hands.

Nokons - I got them because I had to turn my bars a lot to get the bike in my car. I blew out Campy shifter housings within a few months, maybe 50-70 total trips. After I blew out a second set of Campy housing I decided to get a segmented housing made from solid cylinders of metal. THe Nokons fit the bill. The early versions, from the mid 2000s, had finish durability problems, but the ones now I've been using for a couple/few years and they're good.

Quick advantages:
- cable housing can't blow apart and in fact the segments basically don't wear unless they're rubbing something like your frame.
- housing doesn't compress at all, although you have to "seat" the housing initially (meaning against themselves).
- you can lengthen housing if moving cables to a different bike or if you're installing a different bar or stem.
- lighter (although it's not much)
- you can seal most of the housing (I run the liner for most of the cable so the cables aren't really exposed to moisture)
- very flexible so you can do some crazy tight turns with the housing.
- reusable (the blue I got in 2010, black in 2011, silver ones under the tape I got in 2007?).
- easy to get even lengths, just count segments. I do this for the shifter housing from the lever to the downtube.
- reparable since you can replace one segment if necessary. I have all my extra segments in a small take out container with a lid.

Disadvantages:
- cost more - typically sold for brakes only or derailleur only, so be careful if you see a good price for "a set".
- requires 1.1 mm derailleur cables (skinny)
- doesn't hold shape as well as regular housing due to the incredible flexibility of the set up.
- if you are tall or have full length housing (like internal top tube brake cable or disc brakes) then you may need to buy additional segments. I've bought 3 sets over the years and I use most of them on two shorter height bikes. Black one has full length internal brake cable housing. Both bikes are longer, 56.5 cm top tubes, so about the same as a 56-57 cm frame. If you have a 60 cm or size XL then you're realistically going to be very short on the segments.

Some thoughts on Nokons.

A picture from my set up before I dropped the clamp point by 3 cm. Note the front brake cable housing curve, which is much worse now that the tops of the bars are 3 cm lower. You can see the transition to black near the tape, and under the tape I run my very beat up silver housing. I also run the silver inside the top tube.
Thanks for the info on the cables.

OK, if anybody is interested....as I am 54 y/o, 185 lbs. with probable max heart rate of low 190's (last checked several years ago at 195) I was riding 53x19 for 30 min. at 88 rps. It typically took about 26 min. or so to cross into 160 bpm range. Today, after warming up the Fluid 2 to get max fluid resistance, I set out to ride 53x17 at 88 rpm. At only 3 min. 20 sec., I crossed over 160 bpms. At 5 min. I was at 168 bpm. It was getting to be quite painful and that's were I pussed out and backed off. As a recognized rationalization, the Frito scoops and dip started calling my name. I reckon I could have made it to 7 or 8 min. tops had I chosen to suffer on but again, it was getting hard.

CarpeDiem, if I might trouble you once more, could you try 53x12 at 57 rpms and see what kinds of numbers you get i.e. speed and power? I'd like to mash some and see what kind of approximate power I get and how long it takes my heartrate to go over 160 bpm. Thanks again for all your help!
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Old 12-14-14, 11:57 AM
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Originally Posted by whitemax
Agreed, yes I should get a power meter. Thing is, I don't have one and wanted to get some kind of idea of power for this particular workout interval.
As CDR suggested, you could borrow one, but short of that, I don't see why you wouldn't simply use the TrainerRoad power curve estimate. If you read the link I provided, it's built off a lot more study than you, CDR, or I have put into it here, and by virtue of the large sample set, I think is much more accurate than baselining off CDR. But, if you just want your numbers to sound good...
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Old 12-14-14, 12:46 PM
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Originally Posted by chaadster
As CDR suggested, you could borrow one, but short of that, I don't see why you wouldn't simply use the TrainerRoad power curve estimate. If you read the link I provided, it's built off a lot more study than you, CDR, or I have put into it here, and by virtue of the large sample set, I think is much more accurate than baselining off CDR. But, if you just want your numbers to sound good...
So it looks as if their estimates are based off of mph only and do not take into account what gearing is used. Am I reading that correctly?. It seems that the legs would tire out quicker using a bigger gear versus spinning faster with lighter gear to keep the same speed.
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Old 12-14-14, 01:27 PM
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Originally Posted by whitemax
So it looks as if their estimates are based off of mph only and do not take into account what gearing is used. Am I reading that correctly?. It seems that the legs would tire out quicker using a bigger gear versus spinning faster with lighter gear to keep the same speed.
Yes and no.

The power required to turn the wheel over at a particular speed at a particular resistance is independent of cadence. Meaning on a trainer you should use mph only for power comparison. The amount of work required to go, say, 21 mph, is the same whether you're pushing a gear or spinning a gear. The work done is the same.

Your legs will fatigue a bit quicker (but your heart rate won't climb as quickly initially) but the net results are typically the same. In other words if you do a big gear effort or a low gear effort for 10 minutes you'll end up at a similar heart rate. It takes me longer for my heart rate to climb using a big gear but in the end it all washes out. If I start with smaller gears (loading my aerobic system) then as I fatigue I can revert to stressing the muscles more. Or I can start using the muscle side more but I'm overall more fatigued when my heart rate catches up. This is why racers tend to spin most of the time and might use bigger gears for shorter attacks and such.

To illustrate in a different way - Right after I got my power meter I was experimenting to see if I could use different pedaling speeds to climb a particular hill faster. For me it's a 6:30-8:00 effort, it's really steep, and the second half I'm always just trying to keep going, there's no thought of "I need to accelerate". Therefore the bottom of the hill is where I thought I could make the difference.

I tried using bigger gears, smaller gears, longer and shorter cranks, and the end results were close enough that I couldn't factor out one particular variable that was more important than another.

Mind you, this is on a multiple minute hill.

On a 30 second hill then there are some ways to utilize leverage or spinning, depending on what you do well. I'm more a leverage person with high peak power but not much endurance. On such 30 second hills I'm much better in a big gear, roll it over the hill, and I'm good. Other riders are better sitting and spinning. There's one hill in particular that I use as a benchmark as I raced it 5-7 weeks a year for 22? years, typically doing 30-50 laps a week with about 3-4 years where I was doing closer to 80 laps a week. On that hill, for me, I found that using longer cranks and bigger gears really made a difference, even as I got out of shape and heavier. When I'm super fit I can sit and spin but since I have a relatively weak aerobic system and a relatively strong muscular system, it's better for me to load my muscles for short, intense efforts.

However…

There's the whole aspect of training to consider. Cycling isn't like motorsports, where an engine is typically optimized for a particular rpm range. In cycling you train your engine (i.e. your legs) and although there's a coarse "optimal range" (80-100 rpm I think, biomechanically), you can really improve your cycling ability diversity by training at different cadences. For many years, and even now, I'll do low rpm big gear work, like 40-60 rpm in massive gears (53x12, 53x11). I focus on different aspects of the pedal stroke since I can actually think/coordinate my muscles at very low rpms. I also do higher cadence work, typically when my pedal stroke has disintegrated, trying to average 120 rpm for an hour, or doing peak rpm sprints (with virtually zero load). These drills help me smooth out my pedal stroke partially because I'm focusing on smoothing out my pedal stroke. In races I've sprinted at cadences from 70 to 130 rpm, I generally hold 95-110 rpm when sitting in, and, depending on the situation, I'll make efforts at 80-120+ rpm. This is on the road, of course, so with gearing and such. On the track (I've only raced one full season on track) I found myself really limited at the top end and had to make up for my lack of leg speed by using bigger gears. Other riders were much, much, much better than me with pedaling speed and technique.
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Old 12-14-14, 01:42 PM
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Originally Posted by whitemax
Thanks for the info on the cables.

OK, if anybody is interested....as I am 54 y/o, 185 lbs. with probable max heart rate of low 190's (last checked several years ago at 195) I was riding 53x19 for 30 min. at 88 rps. It typically took about 26 min. or so to cross into 160 bpm range. Today, after warming up the Fluid 2 to get max fluid resistance, I set out to ride 53x17 at 88 rpm. At only 3 min. 20 sec., I crossed over 160 bpms. At 5 min. I was at 168 bpm. It was getting to be quite painful and that's were I pussed out and backed off. As a recognized rationalization, the Frito scoops and dip started calling my name. I reckon I could have made it to 7 or 8 min. tops had I chosen to suffer on but again, it was getting hard.

CarpeDiem, if I might trouble you once more, could you try 53x12 at 57 rpms and see what kinds of numbers you get i.e. speed and power? I'd like to mash some and see what kind of approximate power I get and how long it takes my heartrate to go over 160 bpm. Thanks again for all your help!
I don't mind, esp since I'm planning on riding tonight.

However, as suggested above, my data may not correlate well with your trainer's actual resistance. The numbers are just numbers, and being artificially high can be really discouraging when you learn the reality. For example, before I had my power meter, I did some sprints with a powermeter-equipped friend. He told me excitedly that I must be hitting 1600-1800w in my sprints since he was hitting 1200 and I was just annihilating him. Then a brand new racer told me he was hitting 1550 on his new power tap. I finally got a powermeter, ripped out a few sprints, and I was incredibly disappointed to barely hit 1200w. Eventually, when I was a bit better on the bike and it was warmer out, I was hitting 1250-1400w and a couple times hit 1550. However my expectation was that I'd be in the 1800w range and that just never happened. I've won pretty competitive field sprints without breaking 1200w, and I won a race without breaking 900w (in the rain).

Likewise, after having my powermeter for a while, I went to a local gym with my sis-in-law. She wanted me to ride the stationary bikes with her and give her an idea of how real the numbers were as she'd been using them for a while and she was wondering how accurate they were (her friend is a top level triathlete in the area). On a typical training ride I average 150-170w and in races I might hit 200w avg but typically am so tired at that point I can't sprint. Yet on the exercise bike I was holding 400w for long periods of time and did almost 300w for something like 45 minutes. I told my sis-in-law that she should knock a good 30-40% off the numbers, minimum, to get a real wattage. She was really disappointed.

btw I'm 7 years younger, my max HR is realistically in the 180-185 range (I don't know but I haven't hit 187 in something like 10 years and I haven't broken 180 in at least 3-4 years), and 4 weeks ago I was virtually the same weight as you.
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Old 12-14-14, 02:30 PM
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I don't know how much you can trust trainer power curves from the Web. For my Cycleops MAG+, web curves are off literally by a factor of 2 (the trainer eats 200 watt at 20 mph at the highest resistance setting, as measured by the power meter; the only available web curve claims that it should eat 400 watt.)

From general principles, viscosity of the fluid in a fluid trainer drops off rather dramatically with temperature (if it's anything like typical motor oil, viscosity would drop in half for every 30 F), and resistance at constant speed would drop as well as the fluid heats up. So, resistance would vary depending on what you did during the workout, and even on the little things like room temperature and having or not having a fan near the trainer. A short interval at 21 mph with cool fluid would present more resistance than sustained 21 mph. Motor oil also has substantial specific heat capacity: assuming there's ~1 liter of oil in the trainer (complete guess) and there's no heat loss, it takes 1.5 minutes at 300 W to heat the oil by 30 F.
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Old 12-14-14, 05:35 PM
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21.5 mph on the Kurt Kinetic reads about 260 to 280 watts on my Stages powermeter, depending on tire pressure and how hard I crank the clamp down.

That's pretty close to the published curve.


Why don't you just look up the power curve for the trainer you own?
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Old 12-14-14, 06:10 PM
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@f4rrest I take it, from the color, that's Kurt's published power curve? For the record, TrainerRoad say their power curve matches up very nicely to Powertap tests they've done as well:

"In our unscientific tests with our PowerTaps and Kurt Kinetic Road Machines we were within 3 avg watts for our intervals...so pretty darn accurate. You can get a run down on the Kurt Kinetic Virtual Power Curve here."

I don't quite understand what the basis is for reasonable skepticism of "web power curves" either... unless the same gross level of discernment that is suggested by "web power curves" indicates a similar kind of sloppiness in reading and understanding what the charts say.
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Old 12-14-14, 08:33 PM
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Yeah, it's hotlinked https://kurtkinetic.com/files/kurtki...luidPCurve.jpg
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