Slow uphill and downhill speeds?

General Discussion
1

I use a kickr snap, and the speeds on flats seems very close to what I would get outside. But On gentle 3-4% grade hills it slows me down to 7-8 mph, even though the cadence and gear stay the same. On the wahoo app i am much faster on 3% grade hills.

Also, going downhill I can’t seem to get over 35 mph. Does it slow people down to make sure we don’t go too fast? Even barely peddling I get up to 35 irl.

Thanks for any advice.

2

Do you have the “trainer difficulty” slider at 100%? Note that Zwift simulates downhill grades at half the indicated grade.

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3

Thanks. It is set at 50%. And I understand how that the descents could be slower. But I still don’t understand how speed uphill is so much slower than it should be. I just bout a speed sensor and I am going to try to pair Zwift with that to see if it helps.

4

The change in speed on slopes is due to gravity. When going downhill , objects will accelerate (go faster), and when going uphill they will decelerate (slow down).

5

Have you perhaps got your weight set incorrectly? If it’s way too high (e.g. you used the wrong units) then that will have a big effect going uphill.

6

The speed shown on the wahoo app is irrelevant to your speed in Zwift.

Zwift uses your power output, your weight, virtual terrain detail (incline/decline) as well as other factors (weight and cd of chosen bike/kit, drafting effects, surface rolling resistance, etc.) to calculate a “virtual speed”. That is to say that the speed of your wheel on your trainer is irrelevant as your Kickr Snap is providing power data to Zwift (not speed).

Adding a speed sensor will not accomplish anything.

Main things to check are:

  • That your trainer is correctly calibrated;
  • That your weight is correctly set within Zwift; and
  • That you are aware of the impact of trainer difficulty settings (noting that setting trainer difficulty to 50% will only reduce the resistance your trainer applies in response to virtual gradient and that the progress of your avatar in-game will be calculated using the actual in-game gradient irrespective of TD settings).
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