First, here's my gear:
Head unit: Garmin 830
Rear Hub: Cycleops G2 Hub
Pedals: Garmin X220
Trainer: Yahoo Kickr Snap
I like riding Zwift (despite the bugs). I've been pushing harder on my failing health lately, so I'm spending more time looking at my numbers than ever. 56 now, I've been riding road bikes "seriously" since I was about 14.
A few days ago, Zwift on my laptop wouldn't detect my trainer. I'm not positive what fixed it, but I disconnected the trainer from power for a few minutes, and connected with it from the Wahoo app on my phone for the first time in ... well, a long time. That fixed it up; I could connect from my laptop again.
After that, the distance recorded by my Garmin head unit hasn't been quite right. Before the reconnect incident, the Garmin was recording approximately the same distance that the in-game route had in Zwift. After it, it's about 15% low ... sometimes worse.
I know that the zwift distance is an imaginary number from an imaginary world, computed based on my input weight and power and the frame and wheel choice in Zwift, and drafting and so on. But the numbers were quite close, and were close for a very long time. What happened in that connection reset to knock them out? And if the trainer is adapting resistance for the course, and being moved by my power, why shouldn't they be pretty close?
Here's the actual data:
| Date |
Course Name |
Garmin |
Zwift |
Ratio |
| 2026-06-11 |
Pacer Group Ride |
14.06 |
14 |
0.43% |
| 2026-06-12 |
|
|
|
|
| 2026-06-13 |
|
|
|
|
| 2026-06-14 |
Pacer Group Ride |
12.41 |
13.1 |
-5.56% |
| 2026-06-15 |
Pacer Group Ride |
13.59 |
14.2 |
-4.49% |
| 2026-06-16 |
Outside |
28.44 |
|
|
| 2026-06-17 |
Volcano Circuit |
7.06 |
7.7 |
-9.07% |
| 2026-06-18 |
Beach Island Loop |
12.79 |
13.2 |
-3.21% |
| 2026-06-19 |
Pacer Group Ride |
12.00 |
11.3 |
5.83% |
| 2026-06-20 |
|
|
|
|
| 2026-06-21 |
Pacer Group Ride |
11.74 |
12.5 |
-6.47% |
| 2026-06-22 |
London Flat |
12.02 |
12.3 |
-2.33% |
| 2026-06-23 |
Greatest London Flat |
17.99 |
17.3 |
3.84% |
| 2026-06-24 |
Temple Trek |
11.27 |
11.6 |
-2.93% |
| 2026-06-25 |
Pacer Group Ride |
11.30 |
11.7 |
-3.54% |
| 2026-06-26 |
Twilight Harbor |
6.86 |
7.1 |
-3.50% |
| 2026-06-27 |
|
|
|
|
| 2026-06-28 |
Castle to Castle |
21.07 |
22.6 |
-7.26% |
| 2026-06-29 |
Beach Island Loop |
10.65 |
10.4 |
2.35% |
| 2026-06-30 |
London Flat |
11.86 |
12.2 |
-2.87% |
| 2026-07-01 |
Volcano Circuit |
5.80 |
6.5 |
-12.07% |
| 2026-07-02 |
Tempus Fugit |
18.92 |
20.2 |
-6.77% |
| 2026-07-03 |
Going Costal |
15.38 |
16.5 |
-7.28% |
| 2026-07-04 |
Hilly Route |
8.34 |
9.3 |
-11.51% |
| 2026-07-05 |
|
|
|
|
| 2026-07-06 |
Going Costal |
16.32 |
16.6 |
-1.72% |
| 2026-07-07 |
Loop de Loop |
14.57 |
14.5 |
0.48% |
| 2026-07-08 |
Bon Voyage |
31.98 |
31.5 |
1.50% |
| 2026-07-09 |
Loop de Loop |
12.23 |
12.7 |
-3.84% |
| 2026-07-10 |
|
|
|
|
| 2026-07-11 |
Croissant |
12.69 |
12.4 |
2.29% |
| 2026-07-12 |
Volcano Flat |
13.81 |
13.2 |
4.42% |
| 2026-07-13 |
|
|
|
|
| 2026-07-14 |
Flat Route |
11.69 |
11.2 |
4.19% |
| 2026-07-15 |
Southern Coast Cruise |
25.07 |
24.1 |
3.87% |
| 2026-07-16 |
Casse-Pattes |
24.71 |
24.1 |
2.47% |
| 2026-07-17 |
|
|
|
|
| 2026-07-18 |
Flat Route |
8.93 |
11.2 |
-25.42% |
| 2026-07-19 |
Flat Route |
9.82 |
11.1 |
-13.03% |
| 2026-07-20 |
Going Costal |
13.07 |
16.5 |
-26.24% |
| 2026-07-21 |
Three Musketeers |
31.54 |
36.1 |
-14.46% |