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Calibrating Powerbeam Pro without a Joule

Nemo BrauchNemo Brauch
in General Training Discussions

I gave myself a new Powerbeam Pro for Christmas (yes, I opened the box early ),  I hopped on for the first time yesterday to try out a TrainerRoad workout and realized that the calibration is waaaaaaay off (as in, my Garmin reading the PowerTap hub on the back wheel says I'm at 80 watts while TrainerRoad says the Powerbeam Pro is at 180 watts).

So I figured I need to do a "rolldown" to calibrate it, right?  The only trouble is that to hit the required speed (18-20mph +) according to the Powerbeam Pro, I need to be going at something like 250+ watts according to my Powertap!  There's just no way I can hold that kinda wattage for that long (recovering from surgery or not- my FTP has never even reached 200).

I opted not to buy the Powerbeam Pro with a Joule because I already have more than enough computers and planned to use the trainer with TrainerRoad almost exclusively.  

Any ideas for how I can get this resolved beyond begging one of my guerrilla sized roadie friends to come over and do the rolldown for me?

Comments

  • Paul HoughPaul Hough
    I have a Powerbeam and two G3 Powertap wheels, but I don't use the latter wheels on my Powerbeam. I just do the rolldown every once in awhile and don't worry about it. Nor do I hit 250 watts on the roll-down. I just stay in the 18-22 mph range on an easy gear for 2 mins and then stop while it rolls down. If it comes back calibrated then press. I don't use Trainer Road so I can't imagine why the two are so different. Just going by feel, the Powerbeam seems spot on to what my PowerTaps say at the same level of work out doors.
  • Nemo BrauchNemo Brauch

    The trouble is, to hit 18-20mph I have to be pushing 250+ watts

  • Paul HoughPaul Hough
    I don't get it, cause I don't have to push anywhere near that amount. I haven't even been cognizant of the watts during a rolldown and don't even recall whether it shows them while I am in the rolldown. All I focus is on the speed which is easy to hold in a spin gear. Maybe it's something on the newer Powerbeams. I will have to do a rolldown this week and see what it shows.
  • lancelsulancelsu

    yeah, I don't have to hit 250 watts on mine either?  Do you have it tightened too tight in the back? 

    I love my powerbeam but have no clue how accurate or inaccurate it is on the watts.  I mainly go off of RPE and heart rate when hitting the intervals.  It's nice to have a barometer for training purposes though

  • Brad MarcusBrad Marcus
    @Nemo - call customer support at Saris. Ive had my power beam for almost 2 years and they have helped me on countless occasions. Best to call them while you have access to the trainer. Agree with above re 250 watts - never even close on the roll down!

    I don't use trainer road, so maybe that's where the problem is. My garmin and the joule give identical readings for power.
  • Nemo BrauchNemo Brauch
    FYI- I think I figured it out. I believe I had the tension on the flywheel too tight. The instructions said to keep turning until you hear 2 clicks- but that was way too far. Seems to be working much better now and I can hit 18mph without subjecting myself to a P5 test
  • Brad MarcusBrad Marcus
    @Nemo- Glad you figured it out. Out of curiosity, how do you adjust the power on your trainer without have the joule to control it? Reason I ask is that I just broke the control on my joule and if I don't pre-program my wko prior, I can adjust the power tension by using the joule at this point.
  • Paul HoughPaul Hough
    @ Nemo - I am glad you got it covered, but I did do a rolldown test before my workout tonight. I have an old Joule 3.0 which I use exclusively with the Powerbeam since it has such a large display. I have the Joule for the bike, but it is only a back up because I use a Garmin Edge 500 outdoors. When I start the rolldown, it does not show power, just the coutdown and the speed. The 2 min countdown will not start until I get into tne 18-22 mph band. Then all I see is the speed and the time left until I start the coast. I estimate my power for the test to be something between Z1 and Z2. I do the test in 39-15 gearing. I have a dedicated wheel with Ultegra 12-25 and a trainer tire. That way I can change the wheel on whatever bike I stick on the trainer which is a zillion times easier than changing a trainer tire. The trainer tire has MUCH better grip on a metal roller than a regular tire so I don't have to have much tension at all to get a good grip.
  • Nemo BrauchNemo Brauch

    @Brad- I use TrainerRoad running on my PC to control the Powerbeam Pro.  I've mostly been following workouts but I believe you can use it to adjust watts as you go as well.

    @Paul- That's an interesting benefit to using a trainer tire that I had not considered.  Unfortunately for me swapping the wheel doesn't work because my TT bike has 650c wheels and the road bike has 700s.  I just stick the TT bike on the trainer for the winter and ride the road bike (also has a powertap wheel) outside whenever I can.  

    By the way, the rolldown on TrainerRoad doesn't display power either- just time and speed.  But I happen to have a Powertap wheel on the bike as well, so I can use my Garmin 910XT to display watts from the Powertap Wheel during the rolldown and that's how I knew I was pushing something like 250 watts just to barely hit 18mph.  

    The lesson for me here is- I really don't need to tighten the flywheel very much at all. 

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