Trainer Values & Fitness Test

[racerfern]

I've got my KK Pro setup and I downloaded the profile to my Gen3 iAero. Everything seems OK although the wattage numbers seem low. I've been using an FTP of 230 (down 10 at this time of year). The other day I set out to do a fitness test on the trainer to establish a baseline and I had trouble maintaining 205watts! Has anyone "customized" their trainer settings to more closely match what they see on the road (whether up or down) or am I doing something wrong?

FYI, I've done a couple of intervals that I do out on the road and the numbers are also substantially lower.

Finally, how would I adjust the numbers if I attach the 12# additional flywheel. It has a huge effect on the effort required yet the Gen3 only sees the speed so an adjustment is definitely called for.

[pjboyle]

I have an older model KK fluid trainer and see the same thing you observe. It seems that it is about 10% or more harder to ride a trainer. This is not unique to KK, I think this is a universal from what I have read. I have not adjusted the graph but use different reference numbers for a road workout vs. a trainer workout in an effort to equalize them.

Re: the flywheel question, I think the only time this will be a harder effort due to the weight of the flywheel is when you are starting it spinning from a standing stop (where is that physics book?). After it is spinning the main thing it does is make the operation of the trainer and roller smoother, because it has more inertia keeping it spinning. As you are riding the resistance is coming from the resistance head, not the flywheel. The flywheel just represents some added mass, and since it has a larger diameter than the roller itself, it creates more moment and angular momentum. The trainer could operate without any flywheel at all, it would just be more choppy in relation to your pedal action. In my opinion, the heavier flywheel represents negligible additional power and the watts vs. speed curve will be identical to the lighter flywheel.

PJ (not a physicist) Boyle

[racerfern]

Something else to keep in mind is that the Kurt trainers use a power resistance curve based on a 1% grade

But it also assumes a 165# rider and I'm way over that.

I'm satisfied that my outdoor wattage numbers using a Gen3 are accurate. I would like to see indoor numbers that come closer to reality outdoors so I don't need to make other adjustments to things like TSS values.

Many of us have tweaked our profile and now have consistency and accuracy. I guess I would like to tweak my "indoor" trainer profile.

Re: the flywheel question, I think the only time this will be a harder effort due to the weight of the flywheel is when you are starting it spinning from a standing stop (where is that physics book?).

OK, that makes sense. At some point I'll try two 15 minute sessions at the same wattage, one with the extra flywheel. I'll have to judge by HR and PE if there is a difference.

[tyhaar]

I have a Cycleops Mag Trainer and I've got mine dialed in pretty close to my "FLAT" speed effort on the road. With the graph/speed adjustment with IBike 3, I adjusted my trainer profile to match my HR I would do at a normal effort not windy outdoors. I know HR vs. Wattage is not the way to go as your HR can be different for a absolute number of 200W.

You got to remember from what I have read is your trainer profile is a speed based comparision and the sensor's are useless indoors for tilt/wind?

[nreimche]

Tommyturbo said: I agree that a given wattage on the KK seems much harder than outdoors at higher wattages. Might just be that riding indoors is harder, both physically and mentally?

The mental aspect is a definite factor in other areas in cycling, I believe. For instance, in the book: Training tips for cyclists and triathletes (page 21) Chris Carmichael points out that Lance Armstrong can maintain 185 beats per minute for 30 minutes in training, but in competition he can maintain over 190 bpm's for more then an hour.

So riding out doors may release adrenaline even at lower doses, when we are not noticing the increase in performance (aka-increased power). By contrast we know we get a dose of adrenaline when a large dog lunges at us.

[kb1dqh]

Here's the question that comes to me given all of this:

If one knows their road FTP is x (say 280) and they do an all out trainer test that gives them a FTP (based on KK graphs or iBike forumlas) that is lower than their FTP, should they adjust the power to speed formula so the average speed of the workout equals the road power level? Will that be most accurate for using WKO+, etc?

Thanks,
Jake

[tyhaar]

Here's the question that comes to me given all of this:

If one knows their road FTP is x (say 280) and they do an all out trainer test that gives them a FTP (based on KK graphs or iBike forumlas) that is lower than their FTP, should they adjust the power to speed formula so the average speed of the workout equals the road power level? Will that be most accurate for using WKO+, etc?

Thanks,
Jake

Yes, this is what I did by adjusting the power to speed so the average speed will equal my road power levels.... Seems to work for me.

[racerfern]

Yes, this is what I did by adjusting the power to speed so the average speed will equal my road power levels.... Seems to work for me.

I assume you selected your particular trainer, then switched to the "Coefficients" tab. But which value(s) did you change to get a number you were comfortable with?

[tyhaar]

Yes, this is what I did by adjusting the power to speed so the average speed will equal my road power levels.... Seems to work for me.

I assume you selected your particular trainer, then switched to the "Coefficients" tab. But which value(s) did you change to get a number you were comfortable with?

I pick my particular trainer the Cycleops Mag Low option. I played with the "B" setting in the Coefficients to get what I liked at a perceived effort at certain speeds.

[rruff]

FYI, I've done a couple of intervals that I do out on the road and the numbers are also substantially lower. Finally, how would I adjust the numbers if I attach the 12# additional flywheel. It has a huge effect on the effort required yet the Gen3 only sees the speed so an adjustment is definitely called for.

A few things to consider:

1) The tightness of the roller can have a large effect. I keep the rear tire pumped up and turn the screw 2.5 revs after it just touches. You want it just tight enough so it doesn't slip. The Crr of your tire and tube will effect the speed/power also, but this will be minimized if you keep the roller pressure fairly light.

2) It doesn't matter that the KK "simulates" a 1% grade for a 165 lb rider on a calm day. We are just looking at power... calculated from the speed/power curve.

3) A larger flywheel might make things a little *easier* since it does a better job of simulating the inertia you have on the road... but it won't change the power curve... at all. Riding the trainer seems harder to me just because I have apply force more smoothly around the stroke.

4) You can adjust the coefficients in the KK equation to get a more accurate speed/power curve if you wish.

[rruff]

If one knows their road FTP is x (say 280) and they do an all out trainer test that gives them a FTP (based on KK graphs or iBike forumlas) that is lower than their FTP, should they adjust the power to speed formula so the average speed of the workout equals the road power level? Will that be most accurate for using WKO+, etc?

I would say so.

[coachboyd]

Well, I have noticed when I use my Quarq on the Computrainer, both of them read right at the same wattage. But, to do a 10 minute interval at 330 watts on the Computrainer I really have to suffer through, whereas on the road it's not that big of a deal (well, I'm not talking on the phone or anything). But, since the Quarq and the Computrainer agree with each other, then that has to be the watts I am putting out. . .and yes it is much harder that doing it outside.

But a watt is a watt, it's very common to hold 20 watts less on the trainer, but for keeping track of the workouts and kilojoules and TSS scores I would keep the watts the same but just expect to hold less. For my clients I give them two thresholds, one for outside and one for the trainer.

[gregh3285]

I've made a couple posts about trying to find good curves for Cycleops Fluid 2 trainers. After seeing the responses and looking at the problem from a higher level, I think the best way to look at power on a trainer (at least on a Fluid 2) is as a comparison to other trainer workouts (on the same trainer, with the same power curve loaded into my iBike). You may be able to map trainer rides to outdoor rides to absolute power values, but I, personally, don't try. Once I hit the "trainer season," I use power as a comparison to other trainer workouts. I've found that once I got over the "I'm trying to get absolute accuracy" mindset, I strated concentrating on training -- rather than tweaking my bike computer. I do recognize that this is a philosophy issue where others may deeply disagree, so take it as one guy's opinion.

[MultiRider]

Very interesting posts because I, too, put out slightly less power on the trainer. But I've also found that my HR doesn't hit the same levels as it does outdoor. Perhaps it is a motivation thing. I know I'm more motivated to power up a real hill than to really kill myself for the image of Coach Troy and his stopwatch on the TV. Though the suffering (RPE) actually seems to be quite similar between outdoor and indoor, so I am actually trying really hard. I can't put my finger on the cause, but clearly not putting out the same power indoors as outdoors.

On a related topic, I got a RealRide DVD for Christmas and love it! It is like a video game -- the screen shows riders on the right and left and they pass you and you pass them, the walls of a velodrome or trees on the side of the road fly by, all of which is way more interesting than just watching a bunch of people sweating on trainers. Plus, there's a dashboard with Robbie Ventura's HR, rpm, mph, power output, time remaining, etc at the top and bottom of the screen. It is pretty cool to try to get close to Robbie's wattage. I was able to hang with him on some short intervals at 350w (though he is chatting pretty easily and I was working really hard), but at one point he cranked it up to 700w for some period of time (seemed like forever) while I was have a meltdown from getting to (not sustaining) a 500w effort. My watts were dribbling down while he was powering on.

Anyway, the Vision Quest series are very cool! 8 week training program on one DVD!

[rruff]

I can't put my finger on the cause, but clearly not putting out the same power indoors as outdoors.

I don't really know either, but I think part of it has to do with the momentum.... the trainer has a lot less of it than the road. On the road you can coast through the dead parts of the stroke quite easily, but on the trainer the speed slows down slightly... so you have to change your pedal stroke to keep it from getting choppy. I think this altered pedal stroke (ie resistance) is harder for the leg muscles to negotiate, so power output goes down.

I've been looking into virtual reality trainers since I was thinking it would help with the boredom. What I'm reading though is that they all have horrible momentum modeling, and puny flywheels. The CT is the best in this respect, but I read a report from someone who ditched his CT for a Kurt... and claimed it felt way more realistic. I already have a Kurt and I don't like the way it feels so much. If I shelled out the bucks for a VR trainer I'd want it to feel more like road riding. How hard could it be slap a 20lb flywheel on these things? It isn't like you are going to be carrying it around a lot...

[Alex Torres]

Very interesting topic.

I too was looking for ways to "calibrate" my iPro for compatible or relating (so to speak) outdoor-indoor wattage - regardless of RPE or HR. I use a Fluid² trainer, and use it as integral part of my training routine (1 to 3 times a week) in spite of having good weather all year, so that seemed very important to me.

Reading about the possibility of using 2 different protocols for either indoor-outdoor training and testing made me even more confident about going this way, even though it may demand a bit more work and time.

I just have no idea how I´ll deal about the WKO+ side of this (post ride data interpretation and utilization for my training. Maybe coach Boyd has some tips to share! Perhaps create 2 specific profiles for either indoor-outdoor training would be a logical aapproach? If so... how to do that?