First introduced in May 2019, the Bologna Time Trial Lap course is short but brutal. It’s split into:
- 6.0 km of flat terrain through the historic streets
- 2.0 km climb averaging 9.7%, up to the Sanctuary of San Luca
This makes it close to a 50/50 split of flat and climbing for many Zwifters.
Why Retest?
Since its debut, Bologna TT has been well-studied. But with recent Zwift bike upgrades, earlier conclusions are up for debate. A discussion on the Kaboom Discord prompted this investigation after discrepancies appeared in the ZwifterBikes.web.app.
One Kaboom rider, Eric Brown, found that the app showed a 40-second advantage for the road bikes over TT bikes, which seemed suspicious. Oddly the same rider stats resulted in a different outcome on ZwifterBikes.web.app for myself, with the best TT bike being 10 seconds faster than the best road bike. I’d already established that the TT bike with disk wheels was the fastest setup for my A cat team in previous years’ testing, with a bike swap being a marginal gain with high risk. But I had to know – had the bike upgrade changes shaken things up? This required a test in Zwift to verify.
Organizing the Test
For those that don’t know, Bologna is an event-only world, making testing a little more tricky for those who live in the Eastern states of Australia like myself. It seems that every time I check zwifthacks.com/app/events for events on this course, they are on at “stupid O’clock” in the early morning hours. Luckily, Zwift has a “feature” that accommodates us: I could sign up for an event and then leave my avatar sitting on the side of the road whilst I go to bed and dream about riding away from Pogacar on the queen stage of the 2025 TDF (or the draft gauge being displayed natively in Zwift) and Zwift will automatically place the rider in the event.
I grabbed my morning coffee and greeted my Zwift avatar over a bowl of cold milk and Weetbix drizzled with honey. Hitting the “leave event” icon, I then logged into Zwift on my phone to trigger my original signed-in account in Bologna to be signed out and in a pseudo “offline” mode to ensure I didn’t contaminate my Zwift stats like XP, drops, bike upgrades etc.
WARNING: Despite the notice bar at the top stating stats won’t be counted, your fitness signature is still affected in this mode, so be careful with power durations if you don’t want to impact category rankings.
Test Setup
5 scenarios were tested using different rider profiles:
- 75 kg @ 173 cm @ 350 watts and then a split power 330w on flat, 370w on climb
- 50 kg @ 165 cm @ 5 W/kg and 3 W/kg- 90 kg @ 173 cm @ 250 watts (2.8 W/kg)
Bikes Used
- Road: Level 4 S-Works Tarmac SL8 + Enve SES 7.8 wheels
- TT: Level 5 Cadex + Enve SES 7.8 (Zipp 858/Super9 tested as well in first round in video). Zwift’s Ghost feature was used to compare previous runs and give a good visual guide.
Watch the Video
Results Snapshot
| Rider Profile | TT Bike Time | Road Bike Time | Difference |
| 75kg @ 350W | 16:04.32 | 16:12.17 | TT faster by 7.85 seconds |
| 50kg @ 5W/kg | 15:50.96 | 16:00.09 | TT faster by 9.94 seconds |
| 50kg @ 3W/kg | 23:00.61 | 22:56.60 | Road faster by 4.01 seconds |
| 90kg @ 250W | 22:46.05 | 22:44.01 | Road faster by 2.04 seconds |
“The slower you go, the more time you spend climbing. That makes the road bike more advantageous.” – from the video
Interpretation
- At high power outputs, the TT bike wins thanks to its flat-section dominance.
- At low power outputs, the road bike can outperform due to increasing the ratio of time spent on the climb compared to the flat.
- The differences are small (~9 seconds), and pacing is still a very important factor. As Shane Miller says, “Go hardest when you’re going slowest.”
While TT bikes still hold an edge for strong riders, the Bologna TT course becomes road bike-friendly for less powerful riders. I would estimate that 3.2 W/kg is probably the tipping point where the TT bike starts to see an advantage for most rider sizes. Whilst I did get largely different finish times compared to zwifterbikes.web.app, the predicted time difference between the bikes were within a few seconds. Therefore, I feel that the bike recommendations may well be accurate enough to trust. They seem to line up well with the equipment tests published on Zwift Insider and my previous testing.
Recommendations
- High wattage (3.2 W/kg and above) -> Stick with your TT rig.
- Low power riders -> Consider a lightweight road setup, especially if you spend a long time on the hill.
- Willing to risk it for a biscuit? Try a bike swap: start on a TT bike for the flat and switch to a roadbike after the right hand turn starting the climb. There is potential to gain a large number of seconds for those in the lower categories who are well versed in fast bike swaps.
Your Thoughts
What’s your go-to Bologna TT race rig? Share your thoughts below!
“At high power outputs, the TT bike wins thanks to its flat-section dominance” .. I would rather say, because higher power output means more speed hense more Aero advantage.
The deficit created on the flat is unable to be overcome because the climb is too short for higher power riders. If the climb was twice as long, then the road bike would be the faster choice, just like you see with the lower power riders.
I put out more watts on the climb, so I would try my Aethos with 858 wheels. I can draft the first half of the race so aero is not a big concern. Right?
Sounds like we need a few Tiny Races on Bologna. (road bike, tt bike, tt bikes with draft, then all the way to the top for the fourth race.)
Most TT events are set to no-draft regardless of what bike you’re on.
There are a number of races with draft on Bologna. Then often, your choice is an aero frame or climbing frame. TT bikes are an option at times, but will not get a draft while road bikes will, as stated above.
Definitely choose the road bike if the TT bike won’t get a draft, I do know the WTRL TTT visits Bologna, so TT bike that event given it’s two laps, with a risky group bike swap on second lap climb!
Are the TT Bike times taken with the Enve 7.9 or 858/Super9?
and with the Tarmac on Stage 5, it should be even closer, right?
You’ll see in the video I did the first two runs on the cadex with both wheels, and the time difference was tenth of a second. All subsequent Cadex runs was with the Enve 7.9’s. The difference between the Specialized SL8 level 4 and 5 is a few tenths, possibly a second at most. I may do a follow up if I do a Bologna event in the future to test a level 5 post event.
For a full lap (up & down, or “out and back” if you prefer), I guess the TT bike will win in every case.
For 1.5 lap…you’ll have to run a test to figure out where the break even point is (wrt. power and weight).
It shouldn’t matter what lap you are on, the break even point will be the same, about 3.2wkg is the tipping point for the climb. So for a two lap race simply swap at the bottom of the 2nd climb. Now for very low power riders there maybe an advantage to swapping on first climb at the base and then at the top, I’ve not checked that. The TT bike will maul the road bike from the top of the climb all the way to the finish line and back to base of the climb regardless of power level.
Ive Wished this course to be on demand for years.
Or at least, a workout option. Some Italian climbs would be great also.
Agreed. And also let us setup an event on downtown dolphin as well, for club races.
I’m slow so I’ll stick to the S-Works Tarmac SL8 with my lightest wheels.
Note that zwifterbikes does not appear to understand that multiple laps are an out-and-back and instead treats it as though it was a loop. I think he would need to create a separate course for that case. So just be aware it cannot tell you what bike is best if you have to come back down the hill to the start. I’m assuming we all still believe a TT bike will win in that case….
Little bit odd to test with mixed uphill course, just because it is named “time trial”. Much more important is to know how much faster tt bike is in flat, like in normal tt use. Differences with 150w and 300w is also good information, like use them with all-around wheels against fastest tt-wheels.
The test was purely for this course as it’s featured heavily in TT events. As you can see from the video, there is actually a point where the correct answer for “what bike” changes based on wkg.