Power Explanation
 

Hello all,

I would like to get an explanation on power mainly 700 watt of power. I am looking at purchasing a Tacx Blue Matic trainer and the specs say it has 700 watt of maximum resistance. I don't understand power and I don't have a power meter so I don't know what power output I can deliver. Is the max 700 watt easily attainable? Do I go for another trainer? Will I out grow, out power this one in the future?

http://www.tacx.com/en/products/trainers/blue-matic

Thanks for the input

700W is fine for any type of training short of sprint training. A Cat 3 or above racer may be able to put out 700W for 1 min. A 5 min interval would be more in the range of 300-500W. Most people wouldn't have any problem exceeding the 700W for a short period but not being able to won't affect your training.

Personally, I prefer a fluid trainer like the KK to a magnetic one.

You can probably achieve 700 Watts without too much trouble, but you probably can't sustain it for more than a minute.

Take from that what you will. If you are using it for base training or long intervals you should be fine. If you are doing short intervals, might exceed 700.

Greg, the only I am looking at Tacx is due to their videos, where they tell you what resistance to set the trainer at. Is there a big feel difference between mag and fluid in comparison to price? I know there are tons of people on here recommending the KK road machine.

Laser, this will be my first off-season of training so I am clueless as to what I will be doing. Looking for videos as well. Have seen tons recommend sufferfest and cyclocore

The big difference in feel between fluid and mag is that fluid trainers have progressive resistance, meaning the faster you go the harder it gets, like on the road. With most mag trainers the only way to increase is with a dial control. I say most because Cyclops has a mag model that has a progressive resistance device built in, but I have never tried it.

As indicated above, if you are just spinning the mag models are ok and economical. But for intervals a fluid model is best, and the KK is the only one with a completely sealed resistance unit.

Don't forget the dial on your bike needs to be set to 400W.

There are lots of videos you can use with a fluid trainer as well. Sufferfest videos combined with trainerroad.com make a decent combination that many seem to like. I just listen to music, but check out trainerroad. With a KK and a Garmin cadence/speed sensor you can get a reasonably accurate virtual power meter to guide your workouts.

I agree that you'll be able to do intervals longer than 1' on a 700W trainer. Note that it's not really a matter of the resistance of the unit, but more a traction limit for the interface with the tire. I tried an 800W 1' interval on a trainer, and it just kept slipping

Best video for the trainer: Breaking Bad. I'm getting close to the end of season two...

All of the mag trainers I'm familiar with are progressive resistance. The difference between magnetic resistance and fluid resistance is that mag is linearly progressive, like tires and bearings. Fluid is progressive like, well fluid (air, water, oil) and progresses quadratically. So, on a mag trainer, twice as much speed requires twice as much power. On a fluid trainer, or on the road, twice as much speed requires eight times as much power.

So, one big advantage to a fluid trainer is that it feels a lot more like the road with respect to minor unintentional accelerations, and you also get more normal gearing behavior vs. effort. Many of them also handle their heat better since the fluid is in contact with more of the resistance unit's body, for better conduction to the fins. Lastly, the fluids used do not change viscosity under normal operating temps (even when it's hot enough to sizzle a drop of sweat).

On a serious note, yes, TrainerRoad. I just use it with Netflix - I don't need to be watching Sufferfest, just give me target power and keep me from getting bored.

Ended up ordering a KK road machine.

KK??? what brand is that?


what about noise???

Kurt Kinetic. They aren't silent, but mine doesn't seem much different from the cycle ops fluid I used to use.

Cool thanks!

Good choice. I'm using the KK's R&R and it's great. Considering you'll end up with the same resistance unit, you'll be ok. It's really hard to spin at a good cadence that 50-12 on it for more than a minute.

Thanks, all the reviews were positive so...My concerns is putting a carbon bike on a trainer, I guess we will see what happens. Anybody else use TrainerRoad? of Sufferfest?

I use my carbon bikes on the trainer all the time, and Sufferfest = good.

I tryed the spinnervals DVD they gave me with the trainer. It's a good training, but it's not entertaining or fun at all. My next step is to try a sufferfest :D. I had the same concern about the frame on a trainer, that was one of the reason I chose a R&R instead of a road machine.

Can you explain why the R&R is more forgiving to a carbon bike than a road machine?
Thanks.

I don't know how valid it is, but the thought is that since the bike can move around it isn't subject to as much stress and/or flexing as a regular trainer that holds the rear ridged.

Well It's how I thought it. As I can stand on the bike and move it left and right, I get some of that force goes into motion and removes stress from the bike. I don't have any "official" info about this. Seams logic to me.

Some more thought should go into this assumption. It's possible that an R&R will increase stress on the frame. On the road, when your bike swings when you are out of the saddle, you are still applying mostly downward force into the pedals and countering with upwards force on the bars, so there is some frame twist. Also, in the saddle, gravity is only applying downward force to the saddle, on-axis.

On an R&R, when you are in the saddle, it's possible for you to lean over. Now you have sideloads going into your saddle that you will never see on the road as the R&R fights to keep you upright. Since it allows the swing, you can get much further off center on an R&R than a Road Machine.

Of course, that doesn't mean anything bad will happen. I haven't heard of anyone damaging a frame in a trainer, ever. This is not a significant problem.