Strange Results - CycleOps vs Kurt Kinetic Fluid Trainers



cpurx

New Member
Sep 20, 2011
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I have two background statements, a little history, and my question.

1. I’ve been riding a CycleOps fluid trainer for about two years and have loved it. There’s nothing wrong with it and it has totally changed me as a rider. I’ve read and heard all about the Kurt Kinetic Road Machine and have wanted to try one. I didn’t want to spend the money when my CycleOps is working fine. I ran across a deal I couldn’t pass up and bought an older KK Road Machine (blue not green). I reasoned that it has a lifetime warranty, perfect power curve, looked near new, and for $80 how could I go wrong.

2. I’m doing The Time Crunched Cyclist program from Carmichael Training Systems. January, 2013, it will be a full year in the program, and I recommend it. January 2012 I took what CTS calls a field test and another the first week of October. In January I used a Garmin 305, cadence sensor, heart rate monitor, and the CycleOps. In October I did it with a Garmin 705, cadence sensor, heart rate monitor, and PowerTap. A friend and I were talking about training and he asked me what my power numbers were and my response was of course that I didn’t know. I train by heart rate (HR) and cadence. He wanted to know and asked if I would use his equipment, I wanted to know, and obliged.

I’m in a off period much like what you would do to build base miles. I’m scheduled to ride endurance miles (EM), one hour twice a week, and 2.5 hours on both Saturday and Sunday. Based on my October field test, my EM range should be 80-146 BPM HR, or 110-184w for a power range.

To me, these are very strange results.

Tuesday on CycleOps:
Average RPM, 92
Average Wattage, 163
Average MPH, 14.91
Average HR, 152
Gearing, 39/19

Wednesday on Kurt Kinetic:
Average RPM, 93
Average Wattage, 155
Average MPH, 16.57
Average HR, 142
Gearing, 39/17 I couldn’t believe how much smoother the KK was compared to the CycleOps. It was so smooth and easy I had to go down a gear from the night before. Also, it was quieter but I didn’t feel like I worked as hard, even going down a cog. I was completely thrown off by the difference in numbers and rate of perceived exertion. Tuesday I felt like I went a little too hard but Wednesday felt much better, almost not hard enough, even in a bigger gear and higher cadence. I normally find that my cadence falls toward the end of the hour. If it doesn’t, my HR climbs out of range.

I worried that something wasn’t calibrated properly. I thought about a simple test that might make me feel better about the numbers. I figured I could use the RPMs to see if the millage matched. So I used Sheldon Brown’s Gear Calculator to get a good approximation and the numbers seem about right if you adjust for the high RPM.

Gear Calculator:
Crank, 172.5
Chainring, 39
Cassette, 12-25
Tire, 700/23
RPM, 90
Results:
39/19, 14.4mph
39/17, 16.1mph

So my questions are, what causes this and should I redo my field test, or is one of the two trainers bad?

Thank you for your feedback.
 

vspa

Well-Known Member
Jan 11, 2009
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All trainers have different resistance, thats all. There is no standard way to build them, you have to stick with one of them if you want the ability to compare different workouts,
 

tommyrod74

New Member
Sep 13, 2010
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Originally Posted by vspa .

...you have to stick with one of them if you want the ability to compare different workouts,
Not necessarily. Just ignore all metrics except power (and HR if you care about it). Watts are watts.

Speed on a trainer is about as useful as, well, speed outdoors... that is, not very much at all. Especially if you have a metric like power.
 

tommyrod74

New Member
Sep 13, 2010
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Also, what you are experiencing is going from a trainer with very little inertia (small flywheel) to one with more inertia. The KK is going to feel much more like riding on the road due to the flywheel.

Try a Lemond Revolution if you really want to see how poorly the Cycleops approximates outdor riding.
 

vspa

Well-Known Member
Jan 11, 2009
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tommyrod74 said:
Not necessarily. Just ignore all metrics except power (and HR if you care about it). Watts are watts.
thats not good advice, very shallow way of looking at it,
 

tommyrod74

New Member
Sep 13, 2010
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It's all the advice he needs, actually.

The differing resistance curves between trainers means that the ONLY way to compare between them is by directly measuring power output.

If you can tell us exactly how peadling at 200 watts (for example) on a Cycleops fluid trainer is somehow different from pedaling at 200 watts on a KK trainer, I'd love to hear it.
 

daveryanwyoming

Well-Known Member
Oct 3, 2006
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Originally Posted by tommyrod74 ....The differing resistance curves between trainers means that the ONLY way to compare between them is by directly measuring power output....
Exactly!
 

bansidhe

New Member
Mar 17, 2013
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HI, I know this thread is a bit old but I wanted to chime in and possibly get some feedback.

I have been training on my CycleOps (old, OLD CycleOps) since december as a way of getting back into shape after ACL reconstruction. The only way I can make time go by is with Spinervals DVDs, plain music or a movie just doesnt do it for me.

Anyway, I can get nowhere near the gearing/cadence suggested and have my HR stay within range. And I have noticed that
as I warm up, I will feel a sudden and dramatic increase in tension. Anyway, After reading this I would consider getting a KK. This is not because it is "easier" but because it will give me a wider range of gearing to work with and stay in the prescribed HR zone.

I figure this could actually be a benefit. For example: in the recharge DVD, one starts
in big ring x 23, then big ring by 21, the big ring by 19. Since I cannot push these gears as a recovery ride, I start with small ring 17, hen go to smallx16, then smallx15. but I cannot do small x 15 at 90 rpm and keep my HR down. I have to stay around 16 and even then I need a break...

This does not give me much wiggle room for going down in gears as I am already near the bottom. I figure with the KK if the resistance is actually less per gear I would have a greater range of gears to use. I did notice in the DVDS I have, that the KK's are being used. I am not sure if that is why they are suggesting that gearing or not...


Any feedback?

thanks

bansidhe