Upgrade from Kickr Core v1 to Kickr Core v2 feels MUCH harder

Bugs and Support
1

We have recently added a new Zwift Bike to our training room, a V2, and have since then been experiencing a big power discrepancy. The resistance feels much harder, but the wattage definitely does not reflect that. With trainer difficulty set to 0% and the exact same settings as on the V1, the wattage reads much lower than expected. The wattage is also very fluctuating. I have done a few tests to verify this feeling. Erg mode is off in all tests, except the 4x4 Norwegian.

A zone 2 test, same cadence, same settings, good recovery:

V1: 175w avg, 139 HR – V2: 155w avg, 149 HR (The same gear felt significantly harder. It was hard to maintain 90 rpm in my easy zone 2 gear.)

FTP ramp test:

V1: 300w FTP – V2: 228w FTP (72w decrease, same perceived effort)

A norwegian 4x4 workout:

V1: Could finish all intervals, hard as expected – V2: Could not finish one rep of 110% FTP

Apple Watch calorie readings:

I am aware Apple Watch is not perfect at estimating calories burned, but in my experience, it has been quite precise and always within 1-3% of V1 calorie estimates. On the V2, the discrepancy is 20-25%.

A max wattage sprint test:

I could hit 1000-1100w on the V1, but struggling to hit over 800w on V2.

Other observations:

  • The 3s average watts seem to fluctuate a lot. It can easily jump between 300w and 230w, despite maintaining the same cadence and 0% trainer difficulty.
  • Hitting 90 rpm at first is easy, then resistance seems to increase drastically. Riding on the V1 in general seems much more stable and coherent.
  • On one ride out of 6, it felt completely like V1. My training data (HR and wattage) also reflected this. This led us to believe it was fixed, but the next ride, the issue was back. Exact same discrepancy range, 20-25%.

What have we already tried?

  • Fresh spindown calibration
  • Factory spindown, also after proper heating
  • Changed host device
  • Through-axle is tightened properly
  • We have tried both with and without tennis balls under, no real change.
  • Cloning V1’s height settings did not change anything either
  • We have made sure the firmware is up to date
  • On V2, we are using wifi as the connection method and the wifi is strong.

Is there anything we have missed? Anything to tweak? Or could the bike be faulty?

2

What does Wahoo support say about the difference between the trainers?

Dual recording with a set of power meter pedals would allow you to quantify the difference between pedals and trainers, which might provide some insight into whether either the new or old trainer is more accurate.

3

We haven’t contacted support yet. Figured there could be a small tweak that could fix it before escalating. We do not own any power meter pedals either, and it would be expensive to buy just for troubleshooting. It might be the logical next step, though?

4

I would contact the support team prior to making that sort of investment.

5

I’ve always thought bike shops should have pm pedals available to rent by the day.