AeroPod, PowerPod and Newton

I splurged on a new bike and got a wireless mount for my existing Gen III iBike. Went through calibration rides and headed out for my first ride.

The disturbing thing is that cadence went to zero every time I was standing on a hill. My background in RF engineering notes that the HR sensor is only 6 inches or less from the unit mounted on my stem when I'm standing. The speed sensor is twice as far, and the cadence sensor more like 30 inches - maybe more.

Is my HR sensor signal so strong that the unit can't read cadence when I'm standing on a hill? Cadence and power readings return as soon as I sit down. I *think* I was able to vary position (weight forward vs weight back) while standing on flatter ground to either receive or lose the cadence sensor.

Is there anything I can do to maintain power reading in these circumstances? The PC analysis "tools - fix missing cadence" puts power readings back in these segments after-the-fact.

Charlie

Gee - I think standing means you are not pedaling - no cadence is the correct response in this case. If you are just in an upright position and pedaling on the hill, you may be blocking the signal. Check the location of the speed and cadence sensors and the wireless mount pickup line of sight - also how good are the batteries - if they are weak - weak signal - say only showing 2.7V with a DVM and no load.

Tom

If your cadence is below 33rpm give or take one or two rpm, the cadence will not register. At that point power will go to zero because if the unit thinks you're not pedaling then you're not making power. Was it that low?

This 32-33rpm cutoff is typical of most power meters, not just the iBike.

Hmm. I was cranking over 400 Watts at about 60 to 75 rpm at the time the reading cut out. Blocking line-of-sight? Well, it's a stem mount, so it's not really line-of-sight when I'm sitting, either. Low batteries? It's newly installed from the box. That's possible, but it would not be my first thought.

I haven't had another ride to test it, yet, but it really seemed to be associated with leaning out over the handlebars climbing a steep grade. Stand a little upright (can't do this at 10%), and the meter records cadence and power OK.

Charlie

Beginning to sound a little different - The guys who use this BB a lot tend to think in their terms of use and not how you do - so when you write something out - it gets taken literally - we are slow to figure some things out. We ask dumb questions or make dumb responses to get to the bottom of the issue -

A good battery - before you ever use it will read around 3.1V or higher - depends on brand. After a few hours of use (not at freezing temps) this may go to around 2.9. Anything that reads 2.75V or less is a recycle candidate - unless it was used in Winter. The voltages may vary, but they all read higher outside of the units because there is no loading and so you are reading open circuit (OC) voltages. The iBike reading is under load - so a 3.2V OC could read 2.9V in the iBike, for example.

Are you bumping into the iBike and moving it when standing - or the bracket? You might be lifting it ever so slightly that the contacts are disengaging on the mount... A twist could do it, too.

Tom

I've got a couple more rides, now. I can ride with my wristwatch HRM in place of the iBike HRM and the iBike power readings are fine, whether I'm standing over the unit or whatever. I only get the dropouts on the iBike power reading when I'm using the iBike HRM strap. This may not absolve position and battery readings, but it points more to a RF dynamic range limit on the three input sensors.

Charlie

Now that is truly interesting and a new twist. Would you mind removing, flipping and reinserting the HRM battery. This will create a new wireless code for the HRM so you'll have to scan for sensors within the iBike setup screen.

It's easy to do and you've got nothing to lose.

Hi,
Had exact same thing happen recently. Solved the problem by moving the cadence sensor a but closer to the magnet. Presumably under high load the frame/pedal is flexing sufficiently to make the dist between sensor & magnet too large.

Cheers, c

I had to reset the iBike for other reasons - I'd messed up profiles between the wired mount and wireless on two different bikes. Today's ride (same route, same hills) with the wireless worked OK all the way, even when standing with the iBike HRM.

In the meantime, it's possible that the cadence sensor has been moved closer to the crank. It's possible that high torque on the crank was the source of my problem.

For now, the problem isn't present - at least for one ride.

Charlie