New bike = Superman Power

I was using a speed/cadence/heart rate sensor combo on a Travel Trac Comp Fluid trainer for a long time, and everything worked fine.
Then, I bought an older bike (same tire size) just to use on the trainer with Zwift. I transferred over the sensors, and now I’m getting super human watts while barely pedaling! I tried un-pairing and re-pairing everything, and made sure the correct trainer was selected, but it’s still out of whack!
Any ideas?

2 speed sensor magnets?

I’m using a Garmin speed sensor on the rear hub, exactly the same as on the other bike. Garmin cadence sensor as well, swapped over.
The only thing I can think of is that prior to the swap, I installed a power meter crank arm on the first bike. I noticed a reduction in speed and power on Zwift using it vs. the speed/cadence setup. I took that bike off the trainer to save wear and tear on the (rather expensive) driveline components, and went back to the speed/cadence sensors. I’m wondering if Zwift somehow is taking the numbers from the power meter into consideration, even though it’s no longer paired?
If I can’t get this straightened out, I’m going to have to cancel my subscription, because I can’t ride with anyone!

I would double check this, even unselect it, pick another trainer and the go bat to your corect trainer.

also what tire are you using now, it can be that you are getting tire slipping.

I’ll try it. At this point, I’ll try anything! I’m using the same tire as before (dedicated trainer tire) that I just swapped over as well.
Here are some pre and post-swap readings of Zwift workouts, at the same cadence:
Compare

What type of speed sensor do you use? do you have a bike computer, can you check what speed does the bike computer measure and note the power number at that speed.

It must be something on your side.

Zwift get the wheel speed from your sensor then calculate power given the Trainer and the predetermined power vs speed curve.

I’m using a Garmin sensor, mounts on the rear hub. I think it may be reading too high now, but I don’t know why. I’m going to play around with it, maybe try the one from my road bike, and see what happens.
I did try selecting a different trainer, and then re-selecting my trainer, and it made no difference. I can’t ride in my target heart zones without getting booted for massive wattage, so Zwift right now is pretty useless to me.

1 Like