Hi -

I have my PowerTap paired with a Garmin Edge 510. I always calibrate it before I start my rides and when I stop and the Garmin shuts off. The calibration readings are usually in the mid 500s. Today, it was in the 300s throughout. I also noticed that my power readings were lower than I would have expected, although not by a ratio of the two readings.

Generally speaking, what is the cause and effect of such an unusual calibration? I don't understand this process at all well.

Thanks

Unfortunately a calibration in the 300s means your Powertap has to be sent in to be replaced by Saris, most likely a damaged torque tube.

Why Saris? Don't they make racks and the like?

Yes. They also own CycleOps which sells PowerTap power meters.

Hi - I have a dreary update to this and - again - perhaps someone can shed a flashlight on this for me.
I contacted Saris through email and have gotten an interminable run-around. First, the guy told me to download PowerAgent and update the firmware, without telling me how this is done. He also told me that my unit should calibrate at 515, which I can assure you it never did (usually it did around 550). Then he told me to send a picture of the unit (again, this is a G3), which I found odd. I opened the unit and sent a picture of the hub, but he replied that he needed a picture of the cap itself.

Now, I'm not an expert on power meters by any stretch of the imagination, but I find it odd that the manufacturer needs me to send it pictures of my unit.

Can anyone gently educate me?

With the G3 they moved the electronics to the cap to allow electronic changes (ex ANT+ to BlueTooth) without sending your wheel back to the factory.

They've made multiple versions and the tech support guy wants to see what you have in case there was a recall, it's under warranty, it's a version with a common fault....

Here's a step by step video from PowerTap: