Dynamic-boom vs. Fixed-boom Recumbent Bicycle Power Production

Discussion in 'Cruzbike Class (Riding & Refining your Technique)' started by Jim Parker, Apr 10, 2017.

  1. super slim

    super slim Zen MBB Master

    I think that a wheeled indoor trainer should be used so that a power hub (output power) can be used for indoor and outdoor to reduce the reading differences
     
    Jim Parker likes this.
  2. snilard

    snilard Guru of hot glue gun

    Hello, @Jim Parker, I think that your experiment is not perfectly correct. By measuring Vendetta fixed to turbo trainer you haven't simulated fixed boom recumbent on the road. On turbo you have disabled BB movement but also some other dynamic phenomenona what are present while riding on the road. I am not saying that your results are not correct, I also think that with MBB you can produce more power by adding upper body exercise, but I think that your experiment is not correct way to show it.
     
  3. Jim Parker

    Jim Parker Cruzbike, Inc. Director Staff Member

    I agree it's not perfect. But it is pretty simple and approximates the differences. Not everyone, but perhaps most cyclists, can make more power on the road (vs.trainer), but the explanations for why are varied. I feel like I can make more power on the road, and this small test supports that feeling with some data. I think, for me, the main difference in my power production between the road and the trainer is upper body involvement on the road that isn't there on the trainer.
    Do you have another idea for testing the hypothesis?

    It would be interesting to test RWD recumbent cyclists and see if they make more power on the road vs. the trainer. I would predict not so much.
     
    jond likes this.
  4. super slim

    super slim Zen MBB Master

    I know of a very fast Gnome that has 20 recumbents in his Garage, and half of them are RWD!!!
    I would be surprised if he has not already done tests indoor and outdoor on a RWD!

    If you send me a private message, I will send you his contact details, AND the location of his Private testing Track!
     
    Last edited: Apr 16, 2017
    DavidCH and mzweili like this.
  5. snilard

    snilard Guru of hot glue gun

    You should have 2 bikes with same geometry one MBB, one RWD. You should measure power at cranks to avoid drive train loses. And you should have group of cyclists what will train for some time on booth bikes. This is my opinion.
    It is great what you are doing to prove that MBB is better than RWD. In time when I was deciding about my V20 there was only anecdotal evidence that MBB climbs better and Maria's victory in RAAM. So I believed that Vendetta is fast and it is possible to ride it days in row.
    My winter setup on turbo doesn't fix my boom. I have done John Tolhurs's idea of hanging rear of bike from ground by rope. I have got Elite Qubo trainer what allows some movement forward and backward. It is also not perfectly stiff to twist. Only difference from on road riding is that I am not moving my BB but rear of bike with myself what means that I am lifting myself. I can pull on hendlebars on my turbo and it adds power compared to not pulling. But my feeling is that I cannot produce as much power on turbo as on the road. But I haven't measured it. My hypothesis is that main difference from road are head build in my muscles and adrenalin and endorphins what I have on the road but not at room.
     
  6. jond

    jond Zen MBB Master


    Categorically agree anecdotally with Jim. Lol

    Upper body input whilst present on the kickr is not free and unleashed like on road.

    Heck I think the bike would sustain damage possibly if I bridged on the trainer too many times.

    I make power easier on road with cruzbike technique at higher effort levels riding the bikes design.

    Swing that boom pull on that bar and brace all at optimum cadence and technique and thrills a minute.

    You know it works. Solid no flex design swinging in the breeze. Going out for a ride outside in the sunshine
     
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  7. jond

    jond Zen MBB Master

    One other thing. I have spent last six months on the v 20 kickr .

    Going back to the road required relearning upper body technique to see previous power figures

    So yes yes yes upper body contribution is paramount to mid to high performance output No doubt.

    I need no science to confirm how I feel about my power meters. Lol
     
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  8. RojoRacing

    RojoRacing Donut Powered Wise-guy

    I had to re-tighten my bars after I found they were starting to rotate because of the sprint finish efforts on zwift. When I'm about 1000 watts I seriously question just how stiff the front end of the Vendetta is due to the crazy amount of flex that seems to happen. I've seen similar flexing in track riders on a trainer so it could all just be the same amount of flex.
     
    super slim likes this.
  9. ratz

    ratz Wielder of the Rubber Mallet

    a Dead stiff frame and wheels is a slow frame and wheels. :emoji_fist:
     
  10. RojoRacing

    RojoRacing Donut Powered Wise-guy

    I kind of look at it a different way using gym free weights vs machine. If you can bench 200 lbs using free weights then you can bench a bit more using a benching machine because you don't have to control the effort. Same effort goes into both but one moves more weight in the desired direction. I see the vendetta as free weights and the others as machine controlled.

    Now we all know lifting free weights is preferred because it promotes a better overall workout for the body but machine supported gets you the bigger numbers.
     
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  11. LarryOz

    LarryOz Zen MBB Master

    I agree with Jason - I seem to be able to get higher power numbers (especially for longer times) on my trainer.
    I personally think this is because I am able to concentrate all my energy just on turning the pedals. When I go out in the real world and have to balance, turn, concentrate on traffic, road conditions, etc. that takes a certain amount of energy that I can't put into the pedals.
    I'm not saying that I still can't get a quick power boast from using my upper body but that also takes energy from my body - it is not free - I think it gets a great little rest to the leg muscles, but if you aerobic system is already max'd out I am not sure you are going to get more using your arms in that case.
     
    super slim likes this.
  12. jond

    jond Zen MBB Master

    Larry I reckon you see higher numbers on the trainer because you spend so much time there and when you are on the road those mini hamster bars offer minimal leverage.

    Of course it matters not mate with your performances being so impressive.

    But I do wonder how your performance would change were you able to train all year on road. Maybe a move to Florida.

    I guess the differences we see on the same bikes just adds to the overall experience of john tolhursts great bike.

    Then it is a matter of individual technique specific to your physique and ability.

    Fatigue to aluminium frame sets on the trainer has to be higher at same watts compared to on road.

    And we are talking thoroughbred vendetta frame sets. Be careful and check your frame regularly for on road smashfests. You would not want to become a zwiftistic.

    Besides trainers are simulations. Even with apps. ;)
     
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  13. ElyDave

    ElyDave New Member

    Surely the only way to take the variable of the trainer out of this is to use a hub based power meter and rolling road or rollers? It doesn't matter how much power the rider is producing unless it gets to the road?

    I'm doing my own little experiment at the moment in real world conditions, on a 25km loop out of my front door.

    Tuesday, on my Al framed df set up for audax, wind from southwest, 30.7 kmh ave, hr 151average, 167 max
    Yesterday, on recumbent rwd, wind more northerly, 28.7 kmh ave, hr 144 ave, 161 max

    Showed pretty much what I was expecting on hr terms, but I was expecting the speeds to be closer based on audax experience. I suspect the different wind direction and strength had a large influence, seemed stronger yesterday. I'm assuming power was similar, legs similarly knackered.

    Next test is to put twin 700c wheels back on the bent, try and get a feel for how much drag from the dynohub/26" on it now.
     
  14. LarryOz

    LarryOz Zen MBB Master

    It is always best to run test back to back on the same day. Even then the wind may not be the same even if you intervals are short.
    A power meter is also just about a requirement, as your HR can be very fickle.
    Good Luck and waiting to see more testing results.
     

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