Hammer ERG mode not matching TR prescibed watts

I searched and couldn’t find an answer to the problem I am experincing with my Hammer (v1) and TR Erg mode in 10-15 minute intervals the last couple workouts in MVSPB. I suspect the issue is the Hammer, but want to eliminate TR from the equation first. The problem first came up in Picket Guard at the very last Over of the very last over-under interval of the workout. About two minutes in the over, the ERG watts dropped from about 345 to about 290. You can see where I tried to save the interval by increasing cadence, but the trainer then matched the 290 with my faster cadence. TR was reporting that I was off target, so it seemed like TR was broadcasting 345 watts while the trainer decide to interpret it as 290 watts instead. You can see what I am talking about at the link below.
1/23/20: Picket Guard

I thought it was a one-off, until it happened again the next day in Tallac +4 on the last two intervals. 13 minutes into the 2nd to last interva, ERG drop from 300 to 250 watts where I tried to increase the percentage of intensity in TR to save it to no avail. Went back to normal at the rest period and 11 minutes into the last interval before dropping again from 295 to 260 watts. This time I tried to gear up a couple times and it seemed to save the last minute of the interval.
You can see what I am talking about at the link below.
1/24/20: Tallac +4

So, what do you think is going on? My Hammer did not seem any more hot than usual. Why did gearing up seem to correct the issue on last interval of Talac +4? I am in a lower gear for MTB training purposes, and would prefer to keep it that way to better mimic what I ride outside. I use my CX bike on my trainer with a 40 Chainring and 19 cog, which is very close to the sweet spot ratio I like to ride in on my MTB. So, I am not in a drastic low gear to over-run the trainer.

Thanks for the help!

  • Can you be more specific about “gear up”?
  • What exact shifting did you do?

Probably worth contacting support@trainerroad.com, so they can review your logs and see if the app was sending the right power or now. Sometimes TR can mess up.

You could consider trying a small fan blowing on the open vents to increase airflow. They have been known to overheat at times, and your FTP puts it up enough to cause a problem if the room is stale or there is too much warm are in the area.

Depending on those results, a call to Saris could be in order.

My CX bike is a 1x so I geared up from 19 cog gradually ending up on on 11 cog before the power equalized correctly for the last minute. Keep in mind I never ever shift in ERG. I was jsut trying to save the interval and was shocked it worked.

Also, forgot to mention I was using the Beta software. My plan was to go back to official release and see if I still have the same issue. Now that I think of it, I see I should have reported this to support first since it was in Beta.

Either way, I am in recovery week and won’t see a real test of the issue again utnil next week when I start my Speciality Block. I planned on adding a fan to the trainer to test as well even though I am in a basement where the temps and ariflow from my dual Lasko fans should be plenty fo air flow.

I will reach out to support and see what they say.