Unless you plan to always ride by yourself, drafting is an essential skill for the cyclist–both indoors and out. Here’s everything you need to know about drafting in Zwift.
The goal of drafting in Zwift is to conserve energy, just as it is outdoors. The amount of energy saved by drafting is no “marginal gain”–it is literally the difference between winning and losing in every bike race.
Estimates vary, but the number most often thrown around outdoors is a 30% power savings when drafting behind just one other rider.
Example: you could put out 210 watts while drafting and maintain the same speed as the rider ahead of you who is putting out 300 watts–assuming you’re both the same size, weight, CdA, etc.
Riding in a large pack will reduce wind resistance even more, resulting in greater power savings. Scientists studied the draft affect of a large peloton (121 riders) and found that wind resistance in the “sweet spot” of this large group was only 5-10% what a solo rider would experience. Incredible!
Drafting Power Savings in Zwift
Based on our (admittedly limited) tests, drafting in Zwift behind a single rider gets you a power savings of approximately 25%. Using power emulators on a closed course, we had one rider sustain 300 watts while another ride drafted behind. We found a rider could stay in this 300-watt draft at 225 watts while on relatively flat ground.
Changes in pitch effect these numbers, as gravity comes increasingly into play. Using the above power numbers, the front rider will pull away on an incline. But when a decline hits, it will take even fewer watts to stay in the draft.
The draft effect in Zwift is enhanced in groups of 4 or more riders, but due to the difficulty of setting up a test, we don’t have hard numbers to show just what the “group effect” is.
The Challenges of Zwift Drafting
Zwift HQ has done a commendable job with their drafting algorithms to create something that works well in small and large packs for a variety of riders. That said, drafting in Zwift takes some getting used to, even if you are familiar with drafting in real life. Here are the differences:
- No steering: outside you can steer in and out of a draft. There is no steering on Zwift pavement, which means at times the game places you behind someone you are trying to avoid, or doesn’t place you behind someone you’re attempting to draft behind.
- No brakes: when you ride outside, you can tap your brakes to maintain the proper distance off the back tire of the rider in front of you. There are no brakes in Zwift, so your front to back position in the pack becomes a matter of putting down the right amount of power at the right time.
- Limited and delayed sensory feedback: outside you can feel when you’re in the draft: the air resistance decreases and you don’t have to work as hard to keep the pace. On Zwift, there are very limited cues as to when you are in the draft or not, and resistance does not decrease when drafting. Additionally, if you need to modify your power output to stay in the draft, the response (your avatar moving in response to your power change) is not as immediate as it would be in real life.
Zwift uses the visual cue of sitting up (riding with your hands on the hoods instead of the drops) as an indicator that you are in the draft. It can be a little confusing though, since Zwift will also have your avatar sit up at slow solo speeds.
If you are moving at 33kph or more and your avatar is sitting up (on the hoods), you are in the draft.
Your avatar will begin riding on the hoods, but as you speed up to 32-33kph your avatar will move to the drops. If you are in the drops and begin to slow down, your avatar will move to the hoods as you hit 29-30kph.
The Tron bike has no “sitting up” animation, so even though you are experiencing the draft effect, your avatar will never change position on the Tron.
Drafting Tips and Notes
Draft Boost (Van) Powerup
The draft boost powerup doubles the strength of whatever draft you are experiencing for 30 seconds. It only works if you are in the draft, so use it in the pack to save some energy.
Dial It In
Because of how Zwift’s “sticky draft” works, there is a “wattage window” within which you can hold a rider’s wheel. For example: you may be holding a wheel at 240w, but if you reduce your power to 220w you’ll still hold the wheel.
In a small group, it’s worth easing off the pedals to figure out just how much power you actually need to hold the wheel, so you aren’t putting out more wattage than necessary.
Double Draft Mode
Zwift has an event mode called “double draft” which gives riders twice the standard Zwift draft effect. This is only used in particular events or races and has the effect of keeping the pack together while increasing overall pack speed. Read more about it >
Since Zwift steers for you automatically, you may at times find yourself being steered out of the draft. If this happens while you’re attempting to stay in the draft, simply keep your power at a level that keeps you in a good position to get the draft, and Zwift will typically steer you into the draft soon enough.
TT Bikes Do Not Draft
On Zwift, TT bike frames do not experience a draft effect. You can draft behind a TT rider, but the TT rider will not get any benefit from riding behind anyone else.
Flick that Elbow!
Just like outdoors, you can use the elbow flick motion (F1 on your keyboard, or in your list of motions on the Companion app) to signal to other riders that it’s their turn to take a pull.