The Importance of Bike Selection in Zwift Sprints

We talk a lot about Zwift bike frame and wheel choice here on Zwift Insider. Many Zwifters find it useful that our frame and wheel performance charts present very precise data about how each item in the Drop Shop performs relative to other items in game, helping us all make smart choices for races.

Note: some Zwifters spend lots of time obsessing over their bike choices, while others will tell you it really doesn’t matter. The truth is actually somewhere in between, as explained in “Does Bike Choice Matter On Zwift?”

One topic we haven’t unpacked much here on Zwift Insider is bike choice for sprinting. How much does bike choice matter at sprint speeds? And if it does matter, how should this impact the bikes we choose for races?

Let’s dig in, and ride smarter.

Sprint Test Results

We ran several popular frame+wheel setups through repeated steady-wattage solo sprints on Watopia’s classic Forward Sprint, then averaged the results. Our test bot held 1050W steady (14 w/kg) heading into and throughout the sprint. Results for each particular setup only varied by 2 hundredths of a second or less, meaning test results were precise, with very little variance.

Here are the results:

• Specialized Venge S-Works + DT Swiss Disc: 19.88s
• Tron: 19.95s
• Scott Addict RC + ENVE 7.8: 20.03s
• Canyon Aeroad 2021 + DT Swiss 62: 20.07s
• Specialized Aethos + Lightweights: 20.31s

So you can see that the difference between the two most popular setups for flat/rolling races (Specialized Venge and Tron) is 0.07s, while the difference between the fastest aero setup vs the fastest climber (Specialized Venge vs Specialized Aethos) was 0.43s.

Aero performance in our steady-state flat tests at 300W is an accurate predictor of sprint performance. That is, the most aero bikes at 300W are also the most aero bikes at 1050W.

We did some test sprints at lower power as well (600W, or 6 w/kg). Time gaps between each setup grew a bit due to slower overall speeds, with the Specialized Venge and Tron being 0.09 seconds apart with sprint times of 26.61 and 26.7 respectively. The math is fairly simple here: if sprint length increases by X%, the time gap between setups also increases by X%.

Sprint Time Gaps

Now that we know the basics of time gaps between bike setups, we need to know how much those time gaps matter. Or to put it another way: how much does bike choice factor into winning or losing crucial race sprints?

First, we looked at sprint segment data from a recent set of ZRL races. The Alley Sprint Reverse segment was analyzed since it is similar in length to Watopia’s forward sprint. We looked at the time gap between 1st and 5th place in the segment times for all four categories in Division 1 of three different timezones. Here are the results:

The average gap between each place for all races and categories above was 0.38s.

Next, we picked a handful of scratch races that ended in pack sprints, and analyzed the average gaps between the top 5 finishers in each race. Here are those results:

The average gap between each place for the scratch races was 0.2 seconds.

Losing Sprints Due To Bike Choice

Based on sprint speed test results and our admittedly lightweight analysis of ZwiftPower data, we can say that, on average, bike choice is only going to cost you at most one place in a sprint ranking.

That is, assuming you have a decently fast race bike (not a pure climber), the amount of time lost with a slower race bike compared to a faster one is less than the average gap between each place in a sprint finish.

And while one place may not seem like much, keep in mind in races like ZRL, the difference between places can be worth up to 5 points!

Of course, this is only talking about averages, since this is the only way we can sensibly talk about the data. In actuality, sprints can be won or lost by 1/1000th of a second, and thus it’s possible that running a slower bike setup could cost you more than 1 place. Of course, the opposite is also true: you may lose a sprint by several seconds, meaning a faster bike wouldn’t have helped you one bit.

Implications for Bike Choice

How should these sprint findings impact our Zwift bike choice? I would summarize my thoughts this way: if you think the race is going to come down to a sprint, and you’re going to be in the mix, then you want a bike and wheelset that sprints well.

When I choose an aero bike for a typical drafting road race on Zwift, it’s usually not because of the watts it saves me while sitting in the pack’s draft for 95% of the race. I choose an aero bike because of the edge it gives me in sprints.

On the other hand, if I’m in a race that includes tough climbs, I need to balance the importance of climb performance vs sprint (aero) performance. And that’s a very personal, situational choice.

Conclusions

There are many factors that combine to determine the outcome of a race sprint. You’ve got your own power, of course, and even that is being read from a power meter that probably has a margin of error of 1-2%. But also how you time that power matters, as well as what sort of powerup (if any) you use, other riders’ behavior, and your choice of bike frame and wheels.

Based on the numbers above, I would say bike frame and wheelset selection are definitely a factor in sprint finishes, but they are one of the smallest factors. I would rank the key factors in order of importance thus:

1. Your raw power
2. Your timing
3. Other riders’ behavior
4. Your powerups
5. Your frame and wheelset choice

Your Thoughts

Have you considered sprint performance in bike choice on Zwift? Do you agree with my ranking of sprint performance factors? Share below!