# Power on Trainer Vs Rollers



## zakyma (Jan 25, 2010)

Hello all.

I began doing serious cycling about 1 year ago, I used to have Cycleops fluid trainer. After almost 4 or 5 months I switched to E-motion rollers, becasue it was too much fun than the trainner.

I continued training on the rollers for almost another 6 months then I saw the Bushido trainer with PC upgrade where you can have some virtual reality training and real life DVD trainings for different places. I can put a DVD of Germany or France, climb a hill or moutain and the trainer will adjust the resistance based on the slope. If the resistance is too high you can still reduce using the power mode where you can climb comfortably. All this with the beautiful scenery on HDMI screen is really a nice experience.

I want to cut it short but I have to give some of the background. 

The point is that I feel that it is too hard on the trainer than the rollers on the same amount of watts. I have SRM crankset and I feel 200W on trainner is more difficult than on rollers. Some people say that the trainer is a function of resistance and rollers are function of speed.

Just want your opinion if you already experienced the same thing. I am getting used to it now and I am sure on the road I will be putting higher wattage, bit busy these days but I will try and let you know.

Thanks.

Mohammad


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## atimido (Jun 17, 2009)

I have never tried a trainer, but I was wondering the same thing. I personally have Kreitler 2.25" rollers with the killer kool headwind unit. This setups gives me a workout that I am not 100% convinced a rear-wheel mount trainer could. Although, I have heard that trainers are good if you want to sprint and aren't comfortable standing on your bike while on the rollers. I only use the rollers when its pouring rain or I don't have time to go out for a ride due to my work schedule. Otherwise, I like riding on the road.


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## spade2you (May 12, 2009)

I use my rollers for endurance pace and trainer for resistance/intervals, but I haven't noticed one being harder for the same wattage. I also haven't had a power meter very long, so take that for what it's worth. 

Keep in mind through the various stages of our fitness, we can't always hold the same wattage at the same relative PE. Some days, that may seem easier and other days might be a little harder.


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## Gatorback (Jul 11, 2009)

I think power measurement can vary significantly from trainer to trainer. I have a basic, lower end Cycleops trainer and know for certain that my power meter (a Powertap measuring at the hub) is reading lower than the actual power produced. For a 20 minute time trial my power is 15% less on the trainer than outdoors. That trainer does not have a heavy flywheel. 

With my 3" Krietler Rollers, however, I believe the power measurement is probably accurate and I do not see a discrepancy. 

You may be experiencing something similar with your trainer. If you are riding where your power reads say 250 watts, maybe on the rollers it is accurate and comparable to outdoors but when your power meter reads 250 on the trainer maybe you are really somewhere higher such as 280. I don't know what having and SRM affects the analysis--that is obviously a little different than measuring at the hub.


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## Kerry Irons (Feb 25, 2002)

*Flywheel effect?*



zakyma said:


> The point is that I feel that it is too hard on the trainer than the rollers on the same amount of watts. I have SRM crankset and I feel 200W on trainner is more difficult than on rollers.


The only thing that comes to mind is that maybe you have less flywheel effect with the trainer and so your "dead spot" during the pedal rotation is more sudden/intense. Since you're measuring with the same power device and getting the same power, you should otherwise feel the same level of exertion.


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## Alex_Simmons/RST (Jan 12, 2008)

Gatorback said:


> I think power measurement can vary significantly from trainer to trainer. I have a basic, lower end Cycleops trainer and know for certain that my power meter (a Powertap measuring at the hub) is reading lower than the actual power produced. For a 20 minute time trial my power is 15% less on the trainer than outdoors. That trainer does not have a heavy flywheel.
> 
> With my 3" Krietler Rollers, however, I believe the power measurement is probably accurate and I do not see a discrepancy.
> 
> You may be experiencing something similar with your trainer. If you are riding where your power reads say 250 watts, maybe on the rollers it is accurate and comparable to outdoors but when your power meter reads 250 on the trainer maybe you are really somewhere higher such as 280. I don't know what having and SRM affects the analysis--that is obviously a little different than measuring at the hub.


It has no affect on the power measured/reported by an SRM or Powertap. If it says your power is down, it's because it is.

Some low inertia trainers are simply horrible to train on, especially mag resistance units, and many experience lower power for same perceived exertion level on such trainers.

My blog post on this issue:
http://alex-cycle.blogspot.com/2009/01/turbocharged-training.html


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## ZoSoSwiM (Mar 7, 2008)

On my old trainer 220 watts felt much harder than it does outside.. As wattage went up the feeling of disconnect went up as well.

I recently picked up a Kurt Kinetic Rock and Roll and added in the pro flywheel. Now my wattage inside feels exactly as I would expect it to feel. I really believe it has to do with the extra flywheel mass and decreased roll down.

On the old trainer the instant you stopped pedaling speed immediately started plummeting. On the Kurt it doesn't. Wouldn't think it would make a huge difference but it surely does.

As for comparing to rollers it's about the same on the Kurt as my traveltrak rollers. I like to test indoors for better control. I haven't noticed a disconnect between my indoor and outdoor power.


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## zakyma (Jan 25, 2010)

Alex_Simmons/RST said:


> It has no affect on the power measured/reported by an SRM or Powertap. If it says your power is down, it's because it is.
> 
> Some low inertia trainers are simply horrible to train on, especially mag resistance units, and many experience lower power for same perceived exertion level on such trainers.
> 
> ...




Thanks for the blog reference, it was so helpful and proved that there is a difference between trainer and road riding. 

According to Tacx site "The Bushido also has a very powerful braking system with a flywheel that is entirely integrated into the shell. "

Regards,


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## spade2you (May 12, 2009)

Kerry's dead spot theory makes sense in my mind.


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## Infini (Apr 21, 2003)

I have: 
- Low-end magnetic Cycle-Ops trainer
- Sportscrafter rollers with a magnetic resistance unit
- High-end fluid Cycle-Ops trainer


The cheap trainer would vibrate a LOT at anything over 300 wats or so. There was a noticable difference between that and the rollers - it was harder to maintain the same amount of power on the trainer than the rollers.

My fluid trainer is new and I doubt there is as big of a difference, though I and still doing my long power tests on the rollers and not the fluid trainer. 

I believe the main difference in RPE with the crappy trainer is from the vibrations


EDIT -- the crappy magnetic trainer had little inertia, while the nicer fluid trainer has much more


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