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Bike trainer Testing

ryanrenfroeryanrenfroe
in General Training Discussions

 Used my new bike trainer for the first time during the testing.  Is it normal to feel like a harder ride on the trainer?  It seems that I ride slower speed on the trainer at my normal HR zones than on the road.  Also, RPE and HR goes way up when I try to ride normal average speed for the road on the trainer.  Not sure if I have the trainer set up correctly or if it supposed to be this way.  Its a Kurt Kinetic Trainer.  Thanks for any feedback.

Comments

  • wareagledustywareagledusty

    Ryan,



    my $.02 worth is that "Trainer time" is slower than on the road from an MPH perspective. I can do a 2 hour ride on the trainer with similar power output numbers (t doesn't sound like you are using a power meter) and my average pace for the road will be 2+ miles per hour faster than on the trainer.



    On the road you have varying degrees of resistance or assistance depending on surface conditions of the road, wind, uphill/downhill, etc. You can also take small breaks when riding, many times not even realizing you have done so. On the trainer it is constant effort, which is great for getting your body used to riding steady which is one of the key EN focal points.



    They key is to stick to your zones, whether HR, RPE, or power, equally regardless of whether you are on the trainer or the road. Work is work, if you are hitting your target zones on the trainer then don't worry about the speed or distance metrics, those just don't translate to road metrics on a 1:1 basis.



    What you will find is that even though you are riding a slower average MPH on the trainer perhaps, but hitting those zones, that your average MPH over time outside will increase along with your trainer MPH.



    To be honest I don't know that I have ever looked at MPH or Average Speed when on the trainer. If you are using a power meter then the power metrics will become your new best friend and those are the only #'s you will care to look at. 230w of effort is 230w of effort, whether you are going 12 mph into a strong headwind or 30 mph with an awesome tailwind.  Or, in the case of your question, grinding it out on the trainer.



    Hope this helps.

  • ryanrenfroeryanrenfroe

     Perfect!  Thanks for the response and that is helpful.  I did get power with the trainer and will be using it going forward.  

  • MattAaronsonMattAaronson
    The reality is that the "power curve" of every trainer model is different. At a given power output my Kurt Kinetic will allow a "speed" that is different (lower) than my Cycleops. In fact some of the crappier trainers will change their power curve significantly as the fluid warms up. Ignore "speed" and "distance" on the trainer. They are totally bogus.
  • William JenksWilliam Jenks

    +1 with Matt.



    A few years ago when I was just starting out and did a bunch of (long) indoor rides with guys over the winter, I would feel really horrible about going "15 mph" or whatever when they were closer to 19-20. I knew it didn't mean that much, but now I still never get to 20 on that same trainer and I'm eating those guys for lunch. :-)



    All this said, if you are careful about tire pressure and reproducible clamping, you can use the speed as a qualitative indicator for your day-to-day rides as a bit of a stand-in for power measurement. Not perfect at all, but can be qualitatively useful. But if you want it to mean something even one day to the next all things being equal, you have to be careful with keeping the setup constant.

    (BTW, I have a pretty good trainer ("Fluid 2" from cycleops) and it does change its resistance (once) as it warms up...but it's pretty constant after this first 5 min or so.)

  • ThurmanMermanThurmanMerman
    The speed on the Kurt Kinetic won't match outside riding for a number of reasons. I'm always faster on the Kurt than outside because I weigh 50+ pounds more than Kurt's average ride which is about 165 lbs and the wieght of the rider their power/speed curve is based on. They talk about their power curve here http://www.kurtkinetic.com/powercurve.php

    The power unit sold by Kurt is based on speed and is just a formula which is on the link above. I did alot of testing their formula versus what a PowerTap was for the same ride and found the average PowerTap watts were always lower than the average watts from their formula. Weight doesn't matter on the trainer because you're not pushing your weight, you're pushing the trainer's resistance. Watts on the formula are usually around 10% higher than the PowerTap but got alot closer with intervals. I think this was mainly because at the end of an interval if you coast a little, PowerTap watts goes to zero but Kurt's formula is based on speed and you're still holding some speed in coasting.

    Bottom line is it doesn't really matter. If you're trying to improve, do a test, get a baseline, use the same trainer, and if you see the numbers going up from your baseline, you're improving. Just don't expect the watts and speed to match watts and speed of a power meter on an outside ride.
  • RumpoleRumpole
    Posted By Ryan Renfroe on 08 Jan 2013 09:25 PM

     Used my new bike trainer for the first time during the testing.  Is it normal to feel like a harder ride on the trainer?  It seems that I ride slower speed on the trainer at my normal HR zones than on the road.  Also, RPE and HR goes way up when I try to ride normal average speed for the road on the trainer.  Not sure if I have the trainer set up correctly or if it supposed to be this way.  Its a Kurt Kinetic Trainer.  Thanks for any feedback.

     

    Yes.  The trainer is harder for a couple of reasons.  First is inertia (I have a KK as well).  You just don't coast like you do on the road.  No breaks.  The second reason is cooling.  There's no breeze inside, and you'd be amazed at the heat you generate at 200 watts.  

    Speed on the trainer is useless except for one thing: as a proxy for power.  In other words, make sure that your tires are about the same pressure every time, and that your "warm-up" period is about the same every time, and that the number of turns that you give the dial is the same every time.  Although the speed doesn't translate directly outside, that means that holding that 17 or 18 miles an hour=FTP, or tempo, or whatever.  Every time.  And you can use HR and RPE as confirmatory data points.    

    My indoor numbers are 10 percent lower or so than what I can do outdoors.  The work readily translates.  

     

     

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