Slow uphill and downhill speeds?

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.

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


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.

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).

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.

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).