Lower trainer difficulty for racing?

wow, this is a long thread.

I’m still fairly new to Zwift AND riding. So I’m still working on my understanding in both worlds.

If it’s all about adjusting the gears - why don’t you call it like that ?
Wouldn’t it be easier if you ask the user which setup/gear ratio is used?
And if the user wants to adjust that he could choose from a list of concrete numbers - Zwift is doing the math for the simulation…

So i.e.
I’m using my cyclocross bike on my Kickr. 36/46 in the front - 11/28 rear.
I would prefer if Zwift offered me i.e for an AdZ ie a 34 / x & 11/32
or a standard Road setup for flatter routes.

In addition Zwift could suggest which gearing could be best/standard for my chosen route.

No slider at all.
Just a setting to use my actual gearing hardware on the bike or simulate concrete different hardware.

And I wouldnt be disappointed, when I take my bike out to the next climb and am totally surprised that I:m not able to ride it even if I rode AdZ in Zwift.
Not everyone knows all of this.

Just my 2 cents

Zwift doesn’t care what gear you are in. It only cares about the power in Watts you are putting out. It takes that and plugs it into its algorithm as I understand it.

In free ride mode my sensation is that trainer-difficulty-max is more difficult, because that setting forces me to acknowledge inclines–I tangibly sense that if I don’t put out more power, my speed will drop. Trainer-difficulty-zero allows me to ride around casually, putting out a steady power, because (although I can see the incline on the screen) the trainer resistance isn’t forcing me to acknowledge that I’m on an incline; I can pedal along smoothly, but my speed will drop. It’s likely that people riding around in free ride mode with the trainer resistance at zero (I realize it’s a spectrum, but for the sake of argument…) probably don’t care that their speed drops significantly when on an unfelt incline. Their overall sensation is that they are “TT-ing” their way around the course.
In a race, however, the bottom line is how fast are you going? If you’re going faster than I, and if you can average a faster speed than I, you will win. In this situation, the racer whose trainer resistance setting is at zero does not avoid spikes in power output any more than the racer whose trainer setting is at max–(s)he must respond to changes in speed during the race, or (s)he risks getting dropped just like everyone, since speed requires power. As GPLama’s test video clearly demonstrates, in order to achieve X time (given equal weight, aerodynamics, etc) on a segment, you have to put out Y power regardless of trainer setting. I.e. if trainer-difficulty-zero racer does not respond to the spike in power that trainer-difficulty-max racer puts out in order to maintain V speed on an incline, (s)he risks getting dropped. If we imagine that trainer-difficulty-zero racer isn’t experiencing just as many spikes in power output as everyone else, it’s because we are envisioning a casual free ride experience, not a race (where speed, which requires power, wins). Race dynamics force trainer-difficulty-zero racer to experience spikes in power output and effort every bit as much as trainer-difficulty-max racer’s trainer does.

Wrong. Lactates levels and heart rate will go higher and faster with 100% difficulty.
Why? More max effort on legs and numerous changes in your rythme changing gears.

Depends on your gearing and how hard you are pushing at any given moment.

Yes but gear changes are more often done at 100 than 50.
And just that transition time feels much harder and pimp up your heart rate. Just try and you’ll see.

You an also just spin your legs faster and achieve the same result without changing as many gears.

Sure, but spinning faster does not mean hitting harder legs (for strength power and having faster higher lactates levels) and changing gears more often having heart rate going higher faster too.
In theory 50 and 100 is the same I agree, but practically… no wonder why official races are all at 100%

Do official races specify what kind of trainer you can use too?

100% on a flux isn’t the same as 100% on a direto

Different trainers have different max gradient simulation

The ONLY solution is for Zwift to give everyone an identical smart bike as part of their subs and then lockout any configurable gearing and trainer difficulty during races :rofl:


After much consideration and trial It seems to me that yes, sliding the difficulty down to 50% makes the hill 50% easier but also 50% longer, you still have to climb the same altitude but on a flatter slope over a longer distance. it’s pretty clear that the real change is in the gearing and really nothing more than that. lower trainer difficulty means less resistance going uphill and less gravity assistance going downhill. of course you could just go out and install different chain rings and a different cassette but again that’s very expensive and with the difficulty slider you have access to all sorts of different gearing depending on what you want to ride.

It’s also important to note that grinding at lower RPM and high torque is very hard on your tendons and ligaments. This style of riding increases the risk for injury and increases the chances you will experience pain that is not reflective of simple training. It is better for the body for the long haul to spin at high cadence and low torque.
That’s just the opinion of an Ironman triathlete and 55-year-old cyclist who is also a medical doctor specializing in physical medicine and rehabilitation.


It’s not about gears. People say it is because it does have some impact on the gears you use or how often you change them, but it’s actually about the amount of gradient simulation.

One can readily confirm that it’s not all about gearing, since the presumed virtual cassette adjustment isn’t consistent for both up- and downhill. Max setting results in “bigger gears” going uphill, but the opposite for downhill—you can spin out your gearing more easily (big gears should be hard to spin out). Conversely, min setting results in “smaller gears” going uphill, but it’s harder to spin out your gearing on the downhills (small gears should be easy to spin out). Change in gradient simulation explains both scenarios.

lower trainer difficulty means less resistance going uphill

Can anyone articulate an answer to the question, less resistance than what?

These are junk numbers to illustrate the point.

At 100% difficulty - rider doing 100w and travelling at 20kph
The ‘hill’ is a 10% incline, Zwift would place on your avatar a penalty of 50 watts to maintain the same speed. You ride at 150w then same speed is maintained. The penalty of the hill is paid for in watts.

At 50% difficulty - rider doing 100w and travelling at 20kph
The ‘hill’ is a 10% incline, Zwift would place on your avatar a penalty of 25 watts and the other 25w penalty is expressed as a drop in speed of 5kph. You ride at 125w the avatar slows to 15kph. The penalty of the hill is shared between watts and speed.

Less power at a given slope and trainer spindle speed. At zero slope, the power vs spindle speed is identical regardless of trainer difficulty setting. At a given positive slope, the higher the difficulty setting, the higher the power at a given trainer spindle speed (which also means at a given gear/cadence combination).

This does not make it easier to understand, since it’s not clear if you’re talking real speed (cadence times gearing times wheel circumference) or Zwift calculated speed.

I meant Zwift calculated speed. Sorry, I thought saying your avatar made that clear.

As has been debated above the amount of watts needed to get your avatar from point A to point B in a given time is not affected by the trainer difficulty setting but there are different physiological costs.