Zero watts reading when going up hill

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Trettel
Posts: 2
Joined: Sat Oct 16, 2010 4:23 pm

Zero watts reading when going up hill

Post by Trettel »

I recently purchased an Ipro wireless unit and it seems to be calibrated properly when I'm riding the flats. The minute I climb a hill greater than say 1%, the cadence and watts go to zero. When I view the hill % screen, I notice that the grade seems inaccurate. If I'm on a 6% grade, it shows only 1.5 - 2%. It does show the negative number going down the same way. I've done my tilt several times because something seems wrong with that sensor. I'm going to do a scan to be sure my cadence senor is paired properly but it works fine all the time except on a hill.

Any ideas as to what I need to do?
Joe
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lorduintah
Posts: 642
Joined: Fri Jan 11, 2008 9:37 am
Location: Plymouth, MN

Re: Zero watts reading when going up hill

Post by lorduintah »

You might try the following, if you have the tools and gadgets available.

Lay the iBike on a counter top or other similar flat surface - not in the wireless head. Open up the tilt calibration by holding the top button down to get into setup and hit the same button until you get to tilt.

Now hit the center button to initiate a tilt calibration - rotate, the iBike when told to and then back again when told to. Keep the iBike in the same area on the counter.

Now if you have a protractor or some other measurement device - even an iPhone with an inclinometer app - lay a cutting board down and put something under one end. This will leave the board tilted on the counter. Put the iBike on the board point it to to high spot and see if you get the same reading as the iPhone or protractor. Also - rotate the iBike 180 degrees and see if you get a negative of the previous reading when the unit was pointing up.

You can try this for several different elevations and see if they are all consistent - if not then I would say there is a sensor problem. I have noticed about a 2 % slope difference on mine when doing this at around 25% slopes.

Tom
pjboyle
Posts: 54
Joined: Thu Mar 06, 2008 8:22 pm
Location: Pensacola, FL

Re: Zero watts reading when going up hill

Post by pjboyle »

lorduintah has posted an excellent procedure for checking your tilt functionality. However, cadence should be independent of tilt and no matter how poor your tilt cal it would not affect the reported cadence. Does cadence register when you are descending? Since you say the wireless was a recent purchase, I assume the battery in the cadence sensor is new.

Two possibilities are a) that your cadence sensor is positioned right at the limit of the magnet and the change in effort/slope/weight distribution on the frame causes the sensor to not see enough magnetic field when climbing causing reported cadence goes to zero. Or b) you change your body position when climbing and somehow block the signal between the sensor and head unit. I think a) would be a more common problem. I have gone to rare earth magnets on both cadence and speed and these can cure a lot of sins of sensor setup.

PJBoyle
Trettel
Posts: 2
Joined: Sat Oct 16, 2010 4:23 pm

Re: Zero watts reading when going up hill

Post by Trettel »

Thanks for the reply! I am going to try the tilt calc on the table. The techs at Ibike also ask me to do that. I did do a scan to be sure my sensors were picking up and when I rode yesterday, that seemed to solve the problem but can't be certain just yet. I do notice that by standing up, that was definitely a factor. My cadence seemed to be fine on the flat and on the descent so maybe the movement in body position was the cause. I'll also check my battery because although it was new, it was off eBay so maybe it had been sitting for awhile.

I'll post what I find out. Thanks again everyone!
Joe
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