Lag in changing resistance of smart trainer

Just wondering what Zwift are doing about the lag that many of us experience with our smart trainers in changing resistance. For example, ride up the escalator in London. When you get to the top and on to the flat you still get the resistance of climbing the hill for 3 - 4 seconds before it changes. Similar things occur with the S’s in Watopia. The lag really spoils the experience.

What is your ping times? The higher the ping time the more lag you will have.

Hi Nigel, 

This isn’t a cut and dry issue.

-Trainer lag is primarily a hardware problem. Different trainers have different lag times, and some ramp up quicker than others

  • It could also be internet based. A high ping time will lead to a lag. 

More often than not, it’s a combination of things. Thing that we can control, like working on lag time, we definitely are. However, there are some limitations that are out of our control. 

Hi Guys

I’m in New Zealand. My ping time to a server on the west coast of the USA is about 240 - 250ms. Obviously slower than if I was in the USA. I’m on a fibre connection and wired network in my house.

What I can’t understand is why the program can’t have a terrain lag control slider where you enter in how far ahead either in distance or time you want the slope of the terrain to be read from. 

Just on ping time. I can’t see why having a slow ping time might impact the lag of the trainer responding to terrain changes. Surely terrain data is stored locally? I can after all ride Zwift not connected to the internet provided I first start off connected. I’ve done unconnected rides a few times in motels when I’m on limited bandwidth.

You can use Zwift while disconnected from the Internet (but you do have to log in first). So ping time has nothing to do with the lag. Not sure why the Zwift employee brought it up.

Hello, Interesting thread.

I’ve really noticed that top of the subway climb after increasing my Gradient slider. It is the location I use to find my sweet spot of 7/8 on the slider. Going any higher makes that lag at the top almost un-rideable.

I think the lag is just part of Zwift. I see it every time I shift gears going up hill. Someone with a slider at 50% just shoots up a hill and I have to develop a technique to prevent it so I don’t fall behind other riders. It is just something that needs to be done, similar to speeding up when passing a slower rider when you are in a draft. If you don’t, you get stuck to the slower rider.

There is definitely an issue. Whether it is a bug or just part of your smart-trainers logarithm, who knows?

Reaction times of smart trainers might possibly not be fast enough for Zwift changes.

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One more thought on the subject…


Are you zooming up the incline? Move that gradient slider up and ride it realistically in a proper gear. Reaction time is not so bad, though noticeable.