I have a strange questions for the group - I am using Trainerroad for my indoor workouts and I decided to start testing some things. I started recording my power data from my Garmin V3's on my head unit and then comparing them at the end of every ride with Trainer Road and my Wahoo (Kicker) recording its on data.

I started to notice a variance between the two with the Wahoo being higher so what I did was change the Trainerroad settings so that it displays the V3 pedals on the screen but still locks into the Wahoo power and keeps that part consistent.

What I found was at the beginning of the ride the power difference is roughly -7 watts (V3 being lower) and about 30 mins later around -5 watts and then at around 1hr-1:05 it is 0 difference and holds that until 1hr30 but I have not ridden longer yet.

What would be the cause of this you think? Is this a series of the wahoo heating up and the brake getting more "grabby"? I don't have a fan on the wahoo and it is not subjected to any light.

I have calibrated the wahoo on both the app and trainer road, the same with the V3's and I have now tried it both on PC via ANT+ and iOS via Bluetooth and the results are fairly consistent. I also ride in the little ring and fairly high up on the cassette for low "drum" speed.

Thanks everyone for any input, any advice on this and how to correlate this over onto the road when I go outside is a great help!