Calibration of hybrid bike

Post Reply
tmet
Posts: 3
Joined: Mon Dec 04, 2017 4:01 pm

Calibration of hybrid bike

Post by tmet »

Hi! I'm sorry if my questions are stupid, but I don't quite get it...

I've been trying to set up my new Powerpod with my hybrid bike. I did an O&B ride for calibration. I found power levels to be low on flats and downhills, and figured that this might be due to the upright sitting position and larger tires. During the setup process there was no option available for the upright position and not for my 700 x 40 C hybrid tires either. I changed the CDA 0,0650 and Crr to 0,0065. I choose those values partly by guessing and partly based on the elevation graph in Isaac, getting it to show coasting and braking reasonable from what I could remember from the actual ride.

My questions are:
1. Is this the right way to set up the Powerpod for a hybrid bike. Or is there a better and more accurate way?
2. What values are actually calibrated during the calibration process? Tilt? Cda? Crr? wind scaling?
GooseRider
Posts: 58
Joined: Wed May 10, 2017 10:52 am

Re: Calibration of hybrid bike

Post by GooseRider »

Tilt and wind scaling are calibrated. Tilt by assuming that all slopes add to zero and wind scaling by assuming that wind averages to zero. Those assumptions are both true for an out-back ride with no changes in wind.

There is no way powerpod could know actual rolling resistance and aerodynamic drag. You can measure those through coast downs, but probably easier for velocomp to give you estimates. If you want to do the coast downs, you can see the formulas and in the rolling resistance thread.

Thanks,

Morten
tmet
Posts: 3
Joined: Mon Dec 04, 2017 4:01 pm

Re: Calibration of hybrid bike

Post by tmet »

Thanks for the quick response. That makes sense to me.

My next question would be what is recailbrated a few minutes into the ride? The same numbers? In this case: How is this done as you can't do the same assumptions as for an O&B ride?
tmet
Posts: 3
Joined: Mon Dec 04, 2017 4:01 pm

Re: Calibration of hybrid bike

Post by tmet »

Can someone from Velocomp please give me estimates for Crr and cda?
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Calibration of hybrid bike

Post by Velocomp »

You Crr estimate is fine. Please post a .ibr ride file that illustrates your concern.
John Hamann
Post Reply