Early one morning back in October 2024, I drove down to Morgan Hill, California to join a small team from Zwift at the Specialized Win Tunnel. The goal? To spend two days testing various frames and wheelsets in the tunnel in order to establish a realistic delta between the slowest and fastest frames and wheels in Zwift.
You can read all about our tunnel time if you’d like, but you’ll get to experience the result of those tests soon enough: Zwift is rolling out performance changes to frames and wheels in next week’s big update!
Zwift Insider has published mountains of speed tests over the years, so Zwift was nice enough to send over a pre-release game build that allowed us to run our standard tests and publish the results a few days before the release. That’s the post you’re reading now. Let’s dive in!
Why the Change?
Zwifters might wonder: why tweak the performance of all the frames and wheels now, 10+ years into the Zwift journey? It’s a fair question. There are two key reasons why this is happening now:
- Those wind tunnel tests in October showed that the aero performance delta between the slowest and fastest road frames on Zwift was too small, while the delta between the slowest and fastest wheels was too large. This change will make the universe of bikes perform more in line with real-world physics (more on this below).
- With the Bike Upgrades feature releasing soon, Zwift’s game team wanted to make sure they avoided the unrealistic situation of an upgraded slow frame like the Zwift Steel outperforming a fast frame like the Specialized Venge S-Works.
With that out of the way, let’s dive into fresh speed test data for all the road bike frames in Zwift. (We’ll publish separate posts about TT, mountain, and gravel frames in the near future.)
Test Methodology Notes
The following results are from tests done using our standard parameters: a 75kg rider, 183cm tall, without drafting, riding at 300 watts (4 W/kg) steady. If you ride at lower power (and most do!), the time gaps you’ll experience between different frames and wheels will typically be larger than what is shown below.
Flat tests were done on Watopia’s Tempus Fugit since it’s Zwift’s flattest route, while Climbing tests were done on Alpe du Zwift since it’s a long-steady climb.
If you’re interested in comparing these new performance numbers to what’s currently in game, check out our Frame and Wheel data chart pages.
Lastly, an important note about the accuracy of these results. While we present time data with tenths-of-a-second precision, it’s important to understand there is a 1-second margin of error in these results, so it’s probably not worth obsessing over fractional seconds.
Frame Performance Data
Time Savings Over 1 Hour
How many seconds does a frame save over an hour of riding compared to the basic Zwift Carbon frame? (Astute observers may notice that this is a different way of presenting data than our old style of simply displaying raw test results. We think showing the 1-hour time gap is more intuitive.)
Charts are sorted from the best-performing frames to the worst, and you can sort based on flat performance or climb performance.
Sort Chart By:
Flat Performance
Climb Performance
The following bikes are not included in this chart, because they performed worse than the baseline Zwift Carbon frame: Zwift Steel, Zwift Safety, Zwift Atomic Cruiser, Zwift Buffalo Fahrrad.
The following bikes are not included in this chart, because they performed significantly worse than the baseline Zwift Carbon frame: Zwift Steel, Zwift Safety, Zwift Atomic Cruiser, Zwift Buffalo Fahrrad.
Stacked Percentile Rank
This format lets you easily see how frames comparatively perform across both flats and climb. This is useful for selecting the best bike frame for a given race course.
Frame Changes Summarized
The difference between basic and fast frames has increased dramatically in our flat tests with this performance update. Previously (see data here) the fastest frames gained around 19 seconds spread out over an hour. Now, they gain around 75 seconds!
This isn’t because the most aero frames have gotten faster. Rather, Zwift kept the fast frames around the same performance level, but slowed down the mid-range and slower frames.
The performance gap between the basic and best climbing frames, on the other hand, has narrowed a bit. The fastest climbers used to gain about 70 seconds over an hour of climbing, but now they gain 54 seconds.
While most frames didn’t move dramatically in terms of percentile ranking, you may notice a few that did. Two of these are especially notable:
- The Specialized Tarmac SL7 is now a much faster climber, in keeping with the frame’s real-world performance
- The Uranium Nuclear has dropped out of the “fast four” grouping of top aero frames
Wheel Performance Data
Time Savings Over 1 Hour
How many seconds does a wheelset save over an hour of riding compared to the basic Zwift 32mm Carbon wheels?
Charts are sorted from the best-performing wheels to the worst, and you can sort based on flat performance or climb performance.
Sort Chart By:
Flat Performance
Climb Performance
Stacked Percentile Rank
This format lets you easily see how wheels comparatively perform across both flats and climb. This is useful for selecting the best wheelset for a given race course.
Wheel Changes Summarized
In terms of aero performance, the difference between basic and fast wheels has narrowed a bit, from around 72 seconds over an hour (see previous data) to 52 seconds. One big reason for this is Zwift’s new treatment of disc wheels on road bikes, which leads to an interesting performance change you can’t easily spot in the charts above.
Zwift has decided to make all disc wheelsets perform worse on road bikes than they do on TT bikes. They’re still pretty fast on road bikes, as long as climbing isn’t involved. But they are faster on TT bikes. (We’ll unpack this more in future posts.) It’s Zwift’s way of encouraging roadies to use more traditional wheels, while leaving the discs to the time trialists. As it should be.
When it comes to climbing, the difference between basic and fast climbing wheels has halved, from around 16 seconds over an hour to just 8. Zwift has adjusted wheelset weights based on manufacturer’s specifications, so this time gap should be a better reflection of what you’d see IRL.
While most wheels didn’t move dramatically in terms of percentile ranking, you may notice a few that did. Here are the wheelsets we caught that moved up in rank significantly (winners) and down (losers):
- Winners:
- Mavic Cosmic Ultimate UST
- ROVAL CLX64
- ENVE SES 6.7
- Shimano C40
- Shimano C60
- Zwift Tri Spoke
- Losers:
Price Changes
Next week’s big update includes a raft of price changes, and most of those are price increases. Frame prices are holding steady for the most part, but many wheelsets are going up in price.
So if you’ve had your eye on a particular wheelset, you may want to purchase it now – especially if its performance looks strong in the updated charts above.
(On the other hand, there are some new, fast frames being released next week. So you may just want to hold onto your Drops!)
Wrapping It Up
Whew… that’s a lot to digest, right?
There are two things I like about these performance changes. First, I like that we have several high-end bikes to choose from, and their performance varies just enough to make it interesting. Zwift clearly doesn’t want “one bike to rule them all,” and these changes show that.
Secondly, I love that the performance of in-game frames and wheels was modified based on the results of the team’s findings at the Win Tunnel. That means Zwift frames and wheels are performing more in line with their IRL counterparts, which I think is generally what Zwifters want to experience.
We’ll be working on additional posts that dig into the performance of top racing frames and wheels (including their comparison to the Tron bike) in the coming days. Stay tuned, because there’s a lot of news just up the road in regards to bike performance and upgrades.
Questions or Comments?
What do you think of all these performance changes? Got questions or comments? Share below!
