Your riding speed in Zwift’s virtual world is determined by several factors:
- Watts: this is the main factor determining your speed. The more power you’re putting into the pedals, the faster you will go.
- World: road gradient, draft effects, road surfaces, and air density values in Zwift’s virtual worlds all affect the speed of your avatar.
- Weight: lighter riders will go faster on flats and climbs than heavier riders if both are putting out the same wattage. Heavier riders will descend faster. Just like outdoors! Read “How Rider Weight Affects Speed” for specifics.
- Height: taller riders are less aerodynamic than short riders, so the shorter rider will go faster if two riders are holding the same wattage and everything else is equal (weight, frame/wheels, etc). Read “How Rider Height Affects Speed” for specifics.
- Virtual Bike Choice: the frame and wheelset you choose affects your speed, as each frame and wheelset has a weight and aero (CdA) value assigned to it. See our frame and wheel charts for a detailed breakdown of the performance of each frame and wheelset on Zwift.
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So How Do I Get Faster?
You can’t exactly alter Zwift’s physics or your height, but here’s the fun part: you have control over the other factors listed above!
Are you overweight? You’ve come to the right place. Cycling is an incredibly effective low-impact exercise that lets you burn calories without beating up your body. Couple daily rides with a smart diet and you can shed weight safely and quickly while gaining fitness. (Ride Your Way Lean is a good read covering the fundamentals of weight loss for cyclists.)
Want the fastest virtual bike setup possible? We’ve got all the info you need, and then some.
The biggest speed factor, of course, is power. What kind of wattage can you put out, and for how long? Every body is unique, and we’re not going to dig into training plans and philosophies here. What we will do, though, is recommend the “Build Me Up” training plan in Zwift for anyone looking to gain fitness via a proven training program designed by an experienced coach.
And we’ll recommend these two books – the very best resources available for cyclists looking to train smart with power:
Notes on Speed Mismatches
Zwift speed doesn’t match your Garmin speed? Since Zwift uses a variety of factors to mirror real-world physics, pairing your bike computer to your power meter or smart trainer will return a very different distance number than Zwift’s – and that’s as it should be.
Zwift speed doesn’t match your outdoor speed? Zwift simulates outdoor cycling quite well, but no system can factor in every single outdoor riding variable (think potholes, rider posture, and group dynamics for starters). Because of this, some riders have observed that their speed on Zwift doesn’t match their outdoor speed. But there are plenty of sensible explanations for this!
“Keep Everyone Together” feeling slow? The physics of group workouts on Zwift are modified in order to keep all riders together. For most riders, this results in a Zwift ride that feels slower than normal. Similarly, the “Keep Everyone Together” option in Meetups uses some black magic to keep your group together, often resulting in some riders moving faster than normal, while others move slower.
Questions or Comments?
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I think a lot of the difference between outdoor speed and zwift is down to the fact you never stop on Zwift, no traffic lights, intersections to get through etc., slowing down and acceleration has a big impact, and of course wind !!!! on a calm day I find the flat and climbing speeds match pretty well
Agreed! But I think the biggest factor is that you can be in the draft for much of your ride on a busy day in Zwift… and many riders aren’t used to how that affects your speed outdoors.
See https://zwiftinsider.com/zwift-speeds/
Agree! But even so the CdA numbers used by Zwift are comparable to pro riders with their wind-tunnel-honed positions and their speed suits custom-fit to their bodies. The average century rider is a mess, with clothing flopping all over the place, in comparison. People underestimate the effect of this.
“…lighter riders will go faster on flats… than heavier riders if both are putting out the same wattage.”
I’m assuming this is because the heaviest rider’s size/girth increases wind resistance? If riders were putting out the same w/kg—not pure watts—the heavier rider will go faster than the lighter rider on flats and downhills. For average C riders in a race:
50kg rider @ 3.5wkg = 175w
100kg rider @ 3.5wkg = 350w
I meant B riders. Sandbaggers ruin it for everyone.
I wish you could edit comments after the fact. /sigh
At equal w/kg the heavier rider will always have the advantage. At equal watts, unless you’re going downhill the lighter rider will have the advantage.
This is why, as a lighter rider, I am not a fan of Zwift’s w/kg system since often it tends to put lighter riders at a disadvantage
Not entirely sure I agree with lighter riders being at a disadvantage – being a heavier/taller rider I have to put out more watts to have an equivalent W/kg. Climbing is also much harder on heavier riders. Don’t see many 80+kg riders winning races – although it amazes me how many 60kg and under riders there are on Zwift….
lighter riders are at a disadvantage most of the time, unless its a hill the size of box hill or greater, shorter than that a heaveir rider pretty much can dominate on the flats, and downhills. 350+ races says so
I totally agree.
At 6′ 7″ and 85kg, I obviously struggle to keep up with any lightweights on climbs, and then on the flat, I have to push a higher w/kg to stay in a group than any smaller riders because of their superior aerodynamics.
But it’s a lot easier for lighter riders to have a high w/kg.
good article. thanks
how does Zwift and Zwift Power calculate placing for group rides?
Placing for group rides is based on “first over the line”, just like a race.
I don’t think that’s the case for the timed rides. I’ve been several kilometers ahead of the leader and had him place in front of me. Same thing with a friend in an event: He was at least a click in front and placed 20 positions behind me.
For timed group rides, it’s a complete and utter crapshoot so you don’t want to hang your hat on the results of those kind of events. The events over distance are the ones that are ordered by who goes under the banner (and it’s not always the banner you think it is) first.
Why in the world are you trying to race in timed group rides?
I’m not. I was just answering M. Holden’s question about placing in group rides. Speaking for myself, I just found it interesting that Zwift couldn’t keep the finishing order for the timed group rides. Most times it has been comically incorrect.
Basically low weight riders have disadvantage on zwift
I’d say that depends on the race… just like outdoors.
Correct – not just it depends – given the W/KG system and the fact that the draft is less than real life. Holding onto someone doing 50 watts greater than you is much harder in Zwift than real life.
I think it’s the exact opposite.
I’m 85kg and if I were to do 3w/kg, I’d be putting out 255w.
Then if I were to ride with a 50kg rider, they would only have to put out 150w to get the same 3w/kg.
“Only?” For you but not for them. I’m 50kg. 150w is decent effort for me. Have you considered that we all have the same size bikes too, which we wouldn’t in real life?
I would love to see a chart which plotted w/kg vs. speed for flat courses on Zwift vs real-life. I think lighter riders go too fast for their power output at times in Zwift.
Yeah me too, it’s absolutely not a match at this moment. I get that Zwift uses a power meter to calculate speed, but it’s nowhere near the same speed at the same wattage outside. Never will I be able to make a 40km/h ride outside, but in Zwift it’s “no problem” using a Direct Drive.
There also appear to be spots on various routes where Zwift’s programmers (for reasons best known the themselves) have built in slow spots. There is no change in grade, no change in the type of road surface, but speed just gets reduced for an interval. This is very noticeable on a couple of the Watopia routes and in Richmond as well.
I don’t know of any such slowdowns, except for the hairpin turn on London’s Classique.
All other slowdowns I’ve seen can be attributed to false flats and/or a change in road surface. But I’d love to see some data on this if you’ve got it!
Yeah Eric, if you mean the 1st hairpin bend on Box Hill, yeah I come to a virtual stop and spin out…. This has happened since London was created…. When are Zwift going to sort that out…. I’ve got the Full PRL to do this winter and that means 11 times up Box Hill. 😕 🤔🤔
I wish it were possible – well, I suspect it is possible, but I don’t know how – to see the exact gradient that Zwift is applying and telling the trainer at each moment. I’ve long suspected that there’s more variation than the headline integer 0%, 1%, 2% etc, you can feel rolling ups and downs even on constant 0% sections.
If the displayed gradient is an integer-rounded average over the next 10m or 2 seconds or something but the ‘steep bit’ is very brief that would explain the ‘slow spots’ – they often happen at junctions e.g. on Volcano clockwise when the road from the Villas joins, the Trafalgar Square ’roundabout’ in London, plenty of others.
Gradients displayed in Zwift are rounded to the nearest whole number… so 1.4% shows as 1%, while 1.6% shows as 2%, etc.
So yes, there are definitely more gradient fluctuations than you see displayed!
Hi Eric, Your mention of ‘Air Density’ is something I’ve not seen before: “World: road gradient, draft effects, road surfaces, and air density values in Zwift’s virtual worlds all affect the speed of your avatar.” Do you know if air density is different on each World?
I believe it’s the same on all worlds. But Zwift can configure custom values for particular events.
I would assume that could be their way in a sense of creating a more realistic approach to the bigger climbs since the elevation would play a part in the real world?
I was hoping to see actual equations here… it seems from your rider weight tests up L’Alpe that Zwift isn’t solving the conventional power-speed equations, but rather uses some approximation, for example a linearization to avoid solving a cubic equation. In that test the % reduction in time exceeded the % reduction in body weight, which is inconsistent with the standard equations.
why do you claim in this article that lighter riders are faster on flats than heavier riders at the same w/kg, whereas in this article you claim the opposite..? https://zwiftinsider.com/wkg-tests/
The text in the post says “lighter riders will go faster on flats and climbs than heavier riders if both are putting out the same wattage.”
I’m referring to pure watts, not w/kg. Two very different metrics!
ah, bit confusing, i just assumed w/kg. oops!
‘Then there’s wind, which doesn’t exist in Zwift but plays a major factor outdoors, rarely helping but often hindering our speed. ‘
this is massive. They should simulate wind in Zwift
It would be super cool, but since it would only really affect racing, I’m sure it’s low on the to do list.
This is indeed the major difference between riding in the real world and Zwift. I live in The Netherlands, near the cost, so I am quite used to riding against or with the wind. For training purposes I do not think implementing wind as a factor affecting speed would be useful. While just training it helps when circumstances are identical between rides so you can make proper comparisons.
For racing (which I have not done on Zwift yet) it would add an interesting tactical element. Picking the right time to attempt to break away from a group will be harder, because you have to take the wind into account.
Any chance of doing some analysis into the acceleration of frames & wheels? Both from starting at zero; and also when alternating 180W to 220W continuously. In Real Life, a lighter bike is better on the flat in a group because aero advantage is less relevant – and the shifts in speed to hold position in the group is helped by faster acceleration – which is better on a lighter bike. So should be the same on Zwift… So fastest race bikes may not be the aero ones that do well on constant-effort, non-group rides…
ist that now an updated version because Zwift changed algos?
I recall heavier rider always wins at the same w/kg
I am new to Zwift, have completed about 20 rides and am midway through level 12 after the 1st month. I am a 5’5″, 132lb, 68 yo male who normally logs in about 4k miles per season outdoors. I am perplexed that I am consistently averaging 19-21 mph on Zwift routes, depending on elevation, and have only been able to achieve an average of 14-16 mph outdoors, again depending on the amount of elevation gain. I can’t believe that outdoor wind resistance has this much impact on my average speed. My budget limited me to a lower end Saris wheel on smart trainer. I’m wondering if my trainer is not providing realistic performance readings. Any ideas, recommendations?
It’s possible your power isn’t accurate on your trainer – wheel-on trainers are notorious for overstating power. Make sure you’ve got it set up and calibrated accurately per Saris’ instructions.
You also may find this post useful: https://zwiftinsider.com/zwift-speeds/
Thanks for the advice. I’ll check trainer calibration.
Hi guys,
I assume that the power/weight ratio is leading for rider speed.
When I do a race, sometimes I see people with a lower power to weight ratio higher in the race results. How is that possible?
Thanks!
Niels
Hi guys,
Interesting article – I’ve been using Zwift for just over a month now and have been very surprised by the speeds I have achieved…
Typically I ride outdoors on the flat and average 19mph, but on Zwift I am often averaging over 20mph (which I guess is because I’m not having to slow down for corners, head into the wind etc) but I have done a group ride and a crit race when I averaged over 24mph!!
I wish that were possible in real life!
I’m using a wahoo Kickr and am impressed with the overall experience, just not the average speeds
Thanks
Colin
If you can ride outdoors and average 19mph, you can certainly do a crit and average 24mph. Sitting in the pack out of the wind IRL actually gives you more of a % “discount” than Zwift’s regular draft.
Thanks for the reply Eric – I ride outdoors on my own all of the time so hadn’t particularly considered the effect of having a decent draft. This is a great site for a newcomer to Zwift such as myself by the way!
Niels – it’s about staying in the draft, and riding efficiently overall. It may also be that those riders are on the heavier side…
Read more at https://zwiftinsider.com/lower-wkg/
All else being equal, heavier riders do not descend faster in the real world, and I hope not in Zwift.
Maybe so, but why such a huge difference like 10km/hr on flat smooth pavement? Even when I do speed up, it is nothing close to what my “stationary/road” speedometer measures, and then can be up to 20 km/hr behind; it’s like I never even accelerated.
Regarding group rides; OK you want to keep riders together and therefore modify speeds accordingly, however how about disabling this when doing sprints. It adds a short competitive feature, and if the speed adjust was only during the sprint it would allow the slower riders to catch up and the faster riders time to recover. I did a group ride last night; London flat course; and did the Mall Sprint Reverse twice. My times for both segments were identical at 21s, however the power for the first was 169W (just warming up) the second 454W (close to max effort). Very frustrating to get the same times on both after all that effort.
That’s not how the vast majority of group rides on Zwift work – unless they’ve got the experimental “keep everyone together” option enabled (https://zwiftinsider.com/group-ride-rubber-banding/). Most would have your speed be realistic (tied directly to your watts).
Eric, I did a meetup yesterday for MegaPretzel and we started with 6 of us. We finished with 2. The last 50+ KM we were pegged at 46KPH on any flat or climb. For the descents, the speed would pick up only a few KPH. Ultimately, I “got the EPIC KOM” at 12:22 at a blistering 28.4 MPH. So, some kind of Zwift algorithm anomaly? What is your take on this? The RPE we had did align with our WPK but the speed was waaaay off.
Watts, cadence, gear ratio factor into how fast the rear tire revolves. Tire circumference determines how far you travel with each revolution. Those two variable produce your speed. Higher gears and bigger tires take more Watts to turn but it seems like we should know how fast the trainer is turning without having to estimate that from Watts.
All very interesting, thank you.
Hello Eric
In the studies mentioned in the article, do you have the equations with the diferent factors?
My interest it is only curiosity.
All cyclist know in a slope the weight is an important factor and the relative watts are the key on the time to arrive at the finish. But for me it is not clear when you ride in a plane. With the porcentages showed in the articles my doubts are not answered.
Is it possible you share the equations?
So which is more likely to mimic real life road conditions’ speed/ distance ; Garmin or Zwift?
I’d say Zwift.
Since there is a difference between Zwift and Garmin in computing speed then which one gives a better approximation to real life condition in reflecting speed/distance.
Zwift.
Yo siendo un ciclista practicamente nuevo 1 año, me es imposible llegar a 40km/h por mas de 5min aca en zwift llegara. 40KM/h en plano me cuesta poco y nada. Encuentro que para mi gusto es muy falsa la velocidad. Esta bien es un juego pero deberian crear un algoritmo mejor y mas llevado a la vida real. Aunque lo intentan falla mucho este aspecto, llegara 28km/h en zwift es practicamente mi zona 4 en la vida real. Entonces ahora me pregunto las personas que realmente tienen un FTP mayor, estan moviendo velocidad como los del World Tour en Zwift.