As Tour de France cyclists switch between screens on their bike computers and pause them as soon as they cross the line, you may have wondered what they're looking at and recording.To their detractors, the best bike computers make racing more predictable and diminish the breakaway's chances. But they are here to stay despite a recent ruling by cycling's governing body, the UCI. It announced a restriction on bike computer size, in case riders get distracted by the supposed plethora of data at their fingertips. These fears seem to be overblown based on what we've found out about how professional cyclists use their head units in races. Green Jersey wearer Mads Pedersen might have his averages on a different screen, but one we can see only shows current speed, power, BPM, RPM, distance, ride time, and clock (Image credit: Wahoo)Bigger isn't better for racingUnlike some of the UCI's equipment rules, its ruling on bike computer size isn't set to inconvenience elite riders. Computers such as the Wahoo Elemnt Ace are nowhere to be seen, with most riders opting for smaller models for marginally lower weight and drag.Wahoo told us the WorldTour teams it sponsors tend to use the smaller Elemnt Bolt instead of the larger Roam or Ace. Garmin-sponsored teams also prefer its svelter head units in competition over the big Edge 1040 and 1050. LottoIntermarch's Georg Zimmermann says: "I use the Edge MTB because its the lightest option."Bike computers are a good way for pros to save weight because, being removable, they don't count towards the 6.8kg UCI weight limit. Weighing just 58g, Edge MTB is half as heavy as larger models, making it popular among VismaLease a bike riders too.Some riders, like Netcompany-Ineos' Sam Watson, prefer more data and a larger screen in training than in races. "In training I prefer the Edge 1050 because of its large screen," says the former British road race champion, who was not selected for this year's Tour. "Everything is easy to see, and I almost always ride with maps enabled, as I like seeing clearly where Im going."For racing, I use Edge 850. Because its light and smaller, I like to think theres a marginal advantage in it, and during races Im generally not looking at my screen very often and focus on the race itself."I like to train with the Edge 1050 because the larger display is ideal for navigation and makes all my data easier to read. But in races I keep things simple. My maps screen also displays only distance and time."During training, I switch between several screens: one for structured efforts, one for general riding, and a map screen when I am following a route. When I have my map screen on, I also display power and time."Most riders seem to prefer a map garnished with extra fields to help them navigate tricky descents or technical time trial circuits (Image credit: Wahoo)Mapping for safetyInstead of distracting riders, it seems bike computers have a role in safety. "I always have the map on my screen," says current British road race champion Fred Wright, who races with the Garmin Edge 850. "For me, its important to know how long it is until the next corner, especially at the more crucial points in the race. "Alongside the map, I display power and the elevation profile because I like knowing when the next flatter section of the climb is coming up.Wright's Pinarello Q36.5 teammate Tom Pidcock uses his Edge 850 in a similar way."I always use the same data screen: power, speed, lap time, lap distance, heart rate and cadence," says the Olympic cross-country mountain bike champion. "I also have a map showing lap time and the distance to my destination, so I know how far I still have to go.Zimmermann also displays maps on his Edge MTB and configures nutrition alerts. "During races my main screen shows the map with the GPX course, current power output and a timer," he adds. "I use the map to know where were heading and the time to keep track of my nutrition, so I know when its time for me to eat, which is every 30 minutes, and the power data helps me pace myself.Paul Seixas' screen displays metres climbed, altitude, heart rate and maximum speed (Image credit: Wahoo)Data differencesPaul Seixas, the 19-year-old Frenchman who is fourth in the general classification, also has a map screen, but his is busier than most riders'. We caught a glimpse of it on his unreleased Van Rysel RCR-Pro.During stage 14 from Mulhouse to Markstein Le Fellering, he displayed metres climbed, altitude, average heart rate and maximum speed. The elevation data makes sense on a mountain stage, but the other two readings seem less crucial. The other data screen on his Bolt is also quite crammed. It displays current and average power, speed, BPM and cadence, as well as distance and time.His nine data fields contrast to Mads Pedersen's seven. The Green Jersey wearer might have his averages on a different screen, but one we can see only shows current speed, power, BPM and RPM. The Dane must like keeping track of time, as he has clock and ride duration fields. Alex Baudin has kept the polka dot trim around his Bolt from when he wore the climber's jersey earlier in the race. The Frenchman's data screen has a similar layout to Pedersen's, with additional average speed and altitude. Alex Baudin's polka-dot-themed Wahoo Elemnt Bolt has a similar layout to Pedersen's, with additional average speed and altitude (Image credit: Wahoo)Only the essentialsAnother common theme is that riders are also tracking a few data points during races, such as core body temperature and ventilation sensors, but generally don't look at these metrics while racing. Cofidis rider Jenthe Biermans did have the Core heat sensor connected to his Wahoo on the rest-day recon of the individual time trial, which he crashed out of. But this appears to be on a 'training' data screen. His map screen is sparse, with only distance and distance to go at the top. The breakaway star of the 2026 Tour France, Baptiste Veistroffer, also keeps things simple on his Edge 850, which he likes for the "balance of screen size and data visibility."He adds: "The metrics I pay the most attention to are power and heart rate. The screen I use most often is the map page, with distance and power data displayed at the bottom.