My distances/speed seem way off from real life


I have been using my zwift setup for the last week, and its been a ton of fun, but I can’t figure out why the data is so off the real world.

Usually when I bike in RL, I average about 30km in an hour. I normally go at a pretty good pace, but nothing to strenuous, I am a very casual rider (as of now!). I never really pushed myself as I like the long rides (3+ hours) and try and pace myself. I also live in BC, Canada, so tons of hills.

In zwift though, I am biking crazy hard, harder than I ever have in RL, not stopping for a downhill coast or a break for an entire hour workout, legs have never hurt like this before, then at the end it says I only did 15km! No way!

I even cheated the last workout by dropping my weight from 90kg to 70kg, but that only gave like an extra 2km.

I know the fluid2 with a speed sensor isn’t perfect, but I didn’t imagine it being off by almost 2x. Its really frustrating going so slow!

Am I doing anything wrong? Or is zwift just not worth it unless you have a power meter or smart trainer?

Trainer: Fluid2
Speed Sensor:
Tire size set correctly in zwift to 700x25

Hey Steven, when using Zpower and estimation with your Fluid Zwift is calculating your speed based on it’s own in game physics. So it’s not going to be a verbatim representation of your outside workout. Here’s more info on Zpower:

it’s not going to be a verbatim representation of your outside workout.

I didn’t expect it to, but I thought it would be better than 50% error. It’s not even close. It’s not fun killing yourself on the training and biking so incredibly slow in game.

What virtual terrain were you riding on? If you are going up an incline within Zwift your in-game speed will drop.

Speed within Zwift for ZPower is calculated by taking your rear wheel speed and the know power curve of the trainer you selected on the pairing screen and that is converted to watts, with those watts, your weight, in-game virtual elevation changes, in-game bike selected, and in-game drafting your Zwift speed is determined.

What watts are being displayed within Zwift?

My in-game speed and IRL speed are extremely close.

Did you every fix the problem, I’m having a similar issue with my setup. I ride a mountain bike in RL and average about 21/22.5 km/h over 3 hours off road but wide rolling tracks. I’m using a road bike on a Bkool pro 3 smart trainer and not reaching these average speeds.

What are the watts being displayed and what is the route you rode on Zwift?

Please read my post above on of in game speed is determined.

Hi Paul. The wattage varies between 100 and 300 depending on gradient. I weigh 100kg and am 6’2” tall. I’ve only ridden a few routes since December 25th including Yorkshire UCI, NYC 22km course. I’ve set the resistance to 100% which seems to work better on the hills (more realistic feel) But my speed on the flat seems slow and effort required is more intense than RL. I appreciate the speed is calculated through wattage and my average is quite Low, 125/145 depending on course, but I’m not matching my RL speeds on road.

You cannot compare in game speed with IRL speed, there are just too many variables involved.

I would suggest moving the slider for difficulty to 50% and see if that helps.

Thanks Paul, appreciate your response. It has come as a shock to be so slow, but I’ll have to work harder. I bought a cheap old road bike for use on my smart trainer and before putting a training tyre on it, I went for a rolling 64km ride and averaged 28kmh so expected to at least match that speed on a simulated ride. :+1:

Within Zwift do you have it set to metric or imperial?

I have it set to metric although the kms seem to take forever to click over. I may try in imperial, see if there’s any difference in accuracy