Going Aero, Maybe

Hi all,

I’ve been doing some “science” in Zwift based on my efforts in the Zwift TT Club series that wraps up this week. My experiment was done in zone 2 erg mode, 165 watts for me. I used the week four TT route in Watopia on the Tick Tock route. Yesterday I rode it on what was suggested as one of the fastest setups available, which I have been using for the four TTs so far. if you have the points, the Cadex Tri frame and DT Swiss Arc 1100 disk.

With the Cadex Tri/DT Swiss Arc 1100 Disc setup, my time for the Tick Tock segment was 32:06. Today I rode it on my Felt FR (my real-life bike) with Zipp 454 wheels and finished in 32:12. Only six seconds slower. The surprise though, was the Felt FR with the DT Swiss wheels, where my time was 31:59. Seven seconds faster than the suggested best TT setup. I’m going to try the Cadex frame with the Zipp wheels tomorrow and see what sort of time I get. As an FYI, my TT time for the event was 28:10.

So, surprised that my standard frame, the Felt AR, with the DT Swiss TT wheels was 7 seconds faster than one of the recommendations. I think, rather than the Cadex frame, I’ll be riding my Felt for the final TT session. Might try the Felt TT bike to see how it goes.

Hey Bradley. Have you seen: https://zwifterbikes.web.app/

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I hadn’t seen that. Thanks for the link. Seems the Cadex/DT Swiss combo came from the information there. It wasn’t something I came up with. I couldn’t find the power/weight numbers used on the calculations. Based on that info, the Felt FR with the DT Swiss wheels should have been a about a minute slower than the Cadex with the same wheels, not faster.

From ZwifterBikes notes:

All timings and the ranking are estimates based on the standard 75kg rider, riding at 300W, used in the ZwiftInsider performance tests; then churned through a mathematical model that approximates relative flat/climb distances.

…and ZwiftInsider’s notes:


  • Flat tests run on 2 laps of Tempus Fugit at 300 watts steady with an isolated 75kg rider 183cm tall, using basic Zwift 32mm Carbon wheels. This test data is used for all flat results on this page.
  • Climb tests run on Alpe du Zwift using 300 watts steady with an isolated 75kg rider 183cm tall, using basic Zwift 32mm Carbon wheels. This test data is used for all climbing results on this page.
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Thanks for that. Admittedly, I didn’t look too hard. If only I weighed 75kg and rode steady at 300W!

I may have misunderstood the tests your are making - have you taken drafting into consideration for the road bike?


Good question. I did take drafting into consideration. I was in a custom workout for Zone 2, so no drafting.

Looking at the info I found provided by CJ’s links, my Felt FR should have been, if I weighed 75kg and pushed 300 watts, over a minute slower than the Cadex, not seven seconds faster. My thinking is that since I am heavier and pushing fewer watts, I should have been even slower than the numbers from Zwifterbikes suggests to expect.

Just because you are in a workout doesn’t mean drafting stops. If you’re on a road bike during a workout you will still get a draft from other riders.


That’s news to me. I always understood no drafting in workout mode. But Zwiftinsider agrees with you so that muddies the water a bit. Guess I should spent more time here to learn about Zwift because I’ve some clear knowledge gaps even as I approach level 43! Although I can’t say for sure, drafting was intermittent at best. I never attempted to draft, though got caught up in several groups for short periods.

Maybe you’re thinking of workout (WKO) events, which are rubberbanded? ie. everyone goes the same speed regardless of wattage.

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Yeah, could be. Not sure where I got that misunderstanding about drafting in workouts.

Originally, it was stated that there’s no drafting in workouts but I believe it was demonstrated that there is.
You could repeat your test but disconnect from WIFI/ internet.
Everyone else disappears.
Just reconnect when you stop.

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Interesting idea. I’m not all that concerned. I did the testing more out of curiosity and to have a way to pretend to accomplish something as I’m doing the Zwift TT Club series and was wondering how much time the TT setup was saving me over the bike I generally ride that is also my RL bike, minus the super fancy Zipp 454 wheels. Yesterday I rode the Cadex TT bike with the Zipp 454 wheels. The time difference on that frame with the DT Swiss Arc 1100 and the Zipp 454 is 10.64 seconds in Zwifterbikes. Ridibg at 165 watts and 89 kg, seven seconds over Tick Tock in Watopia. Close enough so that I should trust the numbers in Zwifterbikes when deciding on what to ride for an event.