Oscillating Power

I have been using my Kinetic Rock and Roll Smart Control ( wheel on) with garmin V3 pedals for power and cadence connecting to swift via my iPhone 6S

Starting last week i hd problems following a workout with highish (at )
ftp) intervals. ( see below it could have been over shooting, i was getting unusual wheel slip at the high power and i could not keep up?)

Today I’m following 2x 30 min workouts at a steady 200W at steady cadence

the power is oscillating following a sine wave

power goes up to approx 280 then i feel the resistance drop, it goes through 200W and at about 150W i feel resistance increase, and again it overshoots to 280ish before releasing… repeat

Peak to peak is about a minute.

This makes a joke of workouts and trying to ride at a steady wattage.

Anyone else seeing power fluctuations recently?

This only has recently started happening. Coinciding with the recent software updates?

Hi @SteveK

Shuji at Zwift HQ here. Oscillating power is usually indicative of a flaky Bluetooth or ANT+ connection between the speed / power sensor and the computer running the Zwift game app. Before I talk about that, I want to ask if you saw the tire slippage warning in the game? Did you feel the tire actually slip against the roller, or do you think it was the trainer hiccuping?

I uploaded your (partial) log.txt file from yesterday’s first session to zwiftazlier.com, and there’s an error in both BLE and signals. Image 001|596x500

I’d suggest going through your own log.txt files to diagnose local signal issues. Here’s where to find your logs. These are steps you can take to improve BLE interference.

Lastly - you’re running a slightly older version of the game app, but I don’t think that has any bearing on the BLE issues. But it’s worth trying v1.0.48969, which released April 14.

thanks for your email

it was a game of two half’s…

i had paused to write the report after the first 30 min oscillating 200W interval

at the lower power it was hard to see, but when i re-started and hit the next 200W everything was fine with the small corrections i was used to.

Strange other than the pause and the target change nothing had changed

the full 1hr25 ride data would be there now.

wrt to tyre slippage earlier in the week, no the game did not tell me, i could feel and hear the slip, this was at 295W ( 10-12 week FTP=308) something that normally doesn’t usually happen at the wattage. ( I cleaned the tyre prior to this session, and allowed to dry, i’ve ordered a new tyre, the old one is beginning to shred)

I did not notice any slip on this 2x30min 200 W workout ( even at the 280W peaks)

As i said power was from the garmin V3S pedals, the ERG seemed to get into a funny mode.

I have seen problems like this before after i’ve stopped, re started, and things don’t settle down till a new target is reached.

I thought i was on the most recent game app, as is offered as an update for the apple app store. ( option of 2 guest locations)

(I’ve moved to the iphone version ( to tv via HDMI) because of low frame rate i was getting from my 2007 imac, with companion on my ipad pro)

I’ll look at the logs wrt bluetooth connectivity.

Thanks again, now on L35, so lots of km behind me,

with lockdown here in the uk now doing at least an hour a day.

Stay safe Steve.