Cervélo S5 Ultegra Di2 Review: The Fastest Bike I've Tested in 15 Years
Holy speed! 🚀
After 15 years of testing road bikes, I thought I'd felt everything the cycling world could throw at me. Then the Cervélo S5 Ultegra Di2 showed up and completely flipped my expectations upside down.
This isn't just another pretty aero bike with flashy components. We're talking about the same machine that powered Team Jumbo-Visma to three stage wins during the 2022 Tour de France. At 7.5kg for a size 56, you'd expect it to feel hefty, but here's the kicker—it rides like it's made of air and lightning.
The numbers tell part of the story: 13% stiffer at the head tube, 25% stiffer at the bottom bracket, and a 42g drag reduction thanks to those redesigned tube shapes and that distinctive Y-stem. But numbers only go so far. What really matters? Every pedal stroke feels like it's connected directly to rocket fuel.
Now, let's talk elephant in the room—that €9,699 price tag isn't exactly pocket change. But after putting this speed machine through its paces, I've got some thoughts on whether those euros buy you genuine performance or just expensive bragging rights.
Ready to find out what makes this bike so special? Let's break down exactly why the S5 might be the ultimate speed weapon—and whether it deserves a spot in your garage.
Cervélo S5 Ultegra Di2 (2023) Specs and Build Overview
Image Source: GRAN FONDO Cycling Magazine
Time to get nerdy with the good stuff! What you're looking at isn't just another expensive bike—it's a carefully orchestrated collection of components designed around one simple goal: making you faster.
Every single piece on this machine has been chosen with speed as the top priority. Let's break down what makes this bike tick.
Frame: Carbon Aero Design with Y-Stem Integration
The heart of the S5 is its carbon frame, and Cervélo didn't mess around here. Taking full advantage of UCI's updated regulations, they've deepened frame sections and maximized tube shapes—especially around the head tube and bottom bracket where it matters most. The result? A drag reduction of 65 grams [2] [2] compared to the previous version.
That iconic Y-stem isn't just for looks either. The refined integration now uses just one bolt length (making your life easier) while shaving off 53g [2]. Plus, you get infinite tilt adjustments between 0 and 5 degrees for that perfect hand-to-lever position [2].
Groupset: Shimano Ultegra Di2 12-Speed
Here's where things get interesting. The S5 comes loaded with Shimano's latest 12-speed electronic shifting—but it's not fully wireless like you might expect. Instead, it's a smart semi-wireless setup with wireless communication at the cockpit and derailleurs wired directly to an internal seatpost battery [2].
The drivetrain features a 52/36T crankset paired with an 11-30T cassette (some models get 11-34T) [4] [5]. But here's the kicker—Cervélo throws in a 4iiii Precision Pro GEN3+ dual-sided power meter [4]. That's serious value right there.
Stopping power comes from Ultegra R8170 hydraulic disc brakes with Shimano CL800 Centerlock rotors [4]—plenty of confidence when you're flying downhill.
Wheels: Reserve 52/63 Aero Wheelset
The wheels deserve special attention. This isn't some off-the-shelf wheelset—Reserve and Cervélo co-developed these specifically for the S5. The asymmetrical design pairs a 52mm deep front wheel with a 63mm deep rear [6].
Why different depths? The front rim measures 25.4mm inner width while the rear is 24.4mm [6] [82]. This setup optimizes spoke length and tension, giving you better stability when crosswinds try to push you around [7].
The performance gains are real: these wheels test 50g faster in laminar flow and 54g faster in turbulent flow compared to the previous Reserve 50/65 combo [9].
Weight: 7.5 kg (Size 56)
The complete package weighs 7.5 kg for size 56 [10] [3]. That's not featherweight territory, but remember—this is an aero bike, not a climbing machine. The weight reflects the design priorities: cutting through air rather than floating uphill.
Tire Clearance: Up to 34mm
Don't worry about being locked into pencil-thin tires. The S5 ships with 28mm Vittoria Corsa TLR tires but accommodates up to 34mm wide rubber [1] [8]. This gives you options for different road conditions without sacrificing the aero benefits.
More tire width means lower pressures, better comfort, and improved grip—all without hurting your speed. Pretty smart engineering.
How the S5 Actually Feels When You're Riding It
"The S5 shines with outstanding efficiency and is almost playfully fast. There is nothing left to be desired in terms of speed." — Granfondo Cycling, Cycling publication specializing in bike reviews
Image Source: Road Bike Action
Time to get real about what this bike feels like beneath you. After putting the S5 through everything from smooth tarmac to questionable road surfaces, here's the honest truth about its personality.
Steering That Reads Your Mind
The front end? It's like having a direct neural connection to the road. Point this thing where you want to go, and it just goes there. No wandering, no second-guessing—just pure precision.
That 982mm wheelbase (shortest in its class, by the way) makes the S5 surprisingly nimble for such an aero-focused machine. Flowing descents become almost meditative—the bike tracks your chosen line so perfectly you barely need to think about steering. The iconic Y-stem isn't just for show; it keeps everything locked in place when you're pushing hard.
Here's the catch: tight, technical descents demand your full attention. This isn't a forgiving bike that smooths over rider mistakes. You've got to bring your A-game.
Power Transfer That'll Wake You Up
First pedal stroke? Boom. The S5 launches forward like someone just lit a firecracker under your saddle. That 25% stiffer bottom bracket isn't just marketing fluff—you can feel every watt getting converted into forward motion.
Moderate climbs around 5% gradient? The bike stays lively and responsive. But here's where honesty matters: when the road kicks up past 8%, that 7.5kg weight starts showing. The S5 prefers a steady, seated grind over out-of-the-saddle dancing. It's not a lightweight climber, and it doesn't pretend to be.
The Comfort Reality Check
Let's be straight—comfort wasn't the top priority when Cervélo designed this speed machine. But it's not a torture device either.
The 34mm tire clearance is your friend here. Running those stock 28mm tires at 65-70 psi hits a sweet spot between speed and livability. Go tubeless, drop the pressure a bit, and suddenly rough roads become manageable.
Just know what you're signing up for: longer rides on choppy surfaces will remind you this is a race bike first. That aero seatpost and stiff frame don't absorb much road buzz. If all-day comfort is your priority, you might want to look elsewhere.
The bottom line? This bike rewards skilled riders who know how to work with its race-bred personality.
Performance Testing: Speed, Stiffness, and Aerodynamics
Image Source: Rouleur
Time to get serious about numbers. After putting the S5 through months of real-world testing, the data tells a story that matches exactly what your legs feel on the road.
Straight-Line Speed and Aero Gains
Here's where things get interesting. That 42g drag reduction (equivalent to 5.5 watts at 40km/h) compared to the 2014 model [9] isn't just marketing fluff—it's speed you can actually feel. Throughout my testing, I consistently clocked speeds 1-1.5mph faster at the same effort level [10].
I'll be honest, I was skeptical at first. Marginal gains sound great on paper, but do they matter on actual rides? Well, on familiar descents where I'd never cracked 35mph on other bikes, the S5 effortlessly hit 38mph [11]. That's not just bragging rights—that's genuine, measurable speed.
But here's what really impressed me: headwind performance. Most aero bikes feel like they're battling the air, and you feel that battle too. The S5? You can see and hear the wind rushing past, but mentally it doesn't drain you the same way [10]. It's like the bike is doing the heavy lifting while you just enjoy the ride.
Stiffness Under Sprint Loads
Those bottom bracket stiffness improvements of 25% and 13% torsional stiffness gains aren't just engineering speak [12]. Stand up and hammer the pedals—the difference hits you immediately. Every watt goes straight into forward motion [8].
Sure, at 7.5kg, this isn't the lightest race bike out there. But it accelerates like something much lighter, thanks to that exceptional stiffness [8]. When you sprint out of corners or launch an attack, the power transfer feels instantaneous [11]. Plus, that torsional stiffness keeps everything tracking perfectly straight during aggressive cornering [12].
Comparison to Previous S5 and Competitors
The new S5 isn't just faster than its predecessor—it's also 100g lighter while gaining stiffness [9]. Pretty impressive engineering trick, if you ask me.
How does it stack up against the competition? I've tested the Specialized SL7, Pinarello Dogma F, and Colnago V4RS, and the S5 takes the crown for straight-line speed [13]. The shortest wheelbase and chainstays among these bikes give it nimble handling too [13].
Now, the SL7 and V4RS do win on frame weight (around 800g versus the S5's 975g), but the S5's overall package makes it "possibly even the fastest bike" I've ridden [8]. Just remember—this speed demon loves flatter terrain. If you're tackling serious mountains regularly, something like the R5 might suit you better [14].
Pricing and Value: Is the S5 Worth €9,699?
"While the new Ultegra Di2 is phenomenally good, since when is it ok for an Ultegra spec bike to cost a whopping £9,200?" — Cycling Tips, Professional cycling publication
Image Source: Mike's Bikes
Let's talk money. €9,699 price tag isn't exactly loose change you find in your couch cushions.
After putting this machine through its paces, I've got some honest thoughts about whether those euros actually buy you something special—or just expensive bragging rights.
Ultegra Di2 vs Dura-Ace Di2 and SRAM Builds
The S5 lineup spreads across several builds with some eye-watering price jumps. Your Ultegra Di2 model sits at €9,699, while the Dura-Ace Di2 version demands €12,999 [4]. SRAM options? Force AXS at €9,999 and Red AXS at €11,499 (down from €13,499) [4]. Want just the frameset? That'll be €5,499 [4].
What's the difference between all these builds? Mostly groupset weight and gearing tweaks. The Dura-Ace gets a 54/40T crankset versus the Ultegra's 52/36T [15]. But here's what matters—they all share the same Reserve 52/63 wheelset and that incredible frame platform. That's where the real speed lives.
Cost vs Performance Trade-Offs
The Ultegra Di2 build hits the sweet spot. You save €3,300 compared to the Dura-Ace version [4] while giving up maybe 200-300g in component weight. You still get 95% of the performance. The Dura-Ace premium becomes tough to swallow unless you're literally getting paid to race.
The inclusion of that dual-sided 4iiii power meter adds real value [15]. But some reviewers rightfully question whether any Ultegra-equipped bike should command nearly €10,000 [8]. Fair point.
Who Should Consider the Ultegra Build?
This bike makes sense if you're "actually, competitively racing, not just the occasional KOM hunt" [16]. For serious racers chasing tangible performance gains, the price becomes more justifiable.
Weekend warriors looking for pure cycling joy? You might want to think twice. As one reviewer put it: "If performance is your goal then absolutely it represents decent value... but as a bike to own and just ride around on with your friends, I'm not so sure" [16].
Bottom line: This is a specialized racing tool. It excels at winning races but might be overkill for casual rides with friends. Know what you're buying before you write that check.
Final Verdict: The Ultimate Speed Machine, But Not For Everyone
🏁 After thousands of miles on the Cervélo S5 Ultegra Di2, here's the bottom line: this is hands-down the fastest road bike I've experienced in 15 years of bike testing.
Does it deliver on those bold performance promises? Absolutely. The razor-sharp handling, incredible aerodynamics, and explosive power transfer create an experience that's genuinely thrilling. Those engineering numbers—25% stiffer bottom bracket, 13% stiffer head tube—aren't just marketing fluff. You feel every bit of that performance advantage with each pedal stroke.
Here's where it gets interesting: at €9,699, the Ultegra Di2 build hits a sweet spot. You get 95% of the Dura-Ace performance while saving over €3,300. Smart money right there.
But let's be real about who this bike is actually for.
If you're racing competitively and chasing every possible advantage, this machine makes complete sense. The aero gains, precision handling, and that included dual-sided power meter easily justify the premium price. You're not just buying a bike—you're investing in genuine competitive advantage.
Weekend warriors and casual riders? You might want to pause and think. Sure, the S5 is an engineering marvel that'll make you feel like a speed demon. But many of you would get more joy from a less specialized machine that handles varied riding conditions better. The S5 absolutely dominates on flatter terrain and fast group rides, but it's not exactly an all-rounder.
My honest take? Ask yourself what cycling means to you. Racing and winning matter most? Few bikes will serve you better than this speed weapon. Just love the pure joy of riding with friends on weekends? Your money might bring more happiness elsewhere.
The S5 doesn't just perform—it excels. The question isn't whether this bike can make you faster (it can), but whether its specialized capabilities match your cycling dreams. For the right rider, this isn't just a bicycle—it's a precision racing tool that earns every euro of that premium price tag.
FAQs
Q1. Is the Cervélo S5 Ultegra Di2 worth its high price tag? The S5 Ultegra Di2 offers exceptional performance for competitive racers, with its advanced aerodynamics, precise handling, and power transfer. However, casual riders may find better value in less specialized bikes.
Q2. How does the Cervélo S5 perform on climbs? While the S5 excels on flatter terrain and moderate climbs, it may feel less efficient on very steep ascents. For mountainous routes, bikes like the Cervélo R5 might be more suitable.
Q3. What are the key differences between the Ultegra Di2 and Dura-Ace Di2 versions of the S5? The main differences are in groupset weight and gearing options. The Ultegra Di2 version offers nearly identical performance at a significantly lower price point, making it the better value for most riders.
Q4. How does the new S5 compare to its predecessor in terms of performance? The new S5 offers significant improvements, including a 42g drag reduction, 25% increased bottom bracket stiffness, and 13% greater torsional stiffness. It's also 100g lighter while maintaining excellent aerodynamics.
Q5. What type of rider would benefit most from the Cervélo S5 Ultegra Di2? This bike is ideal for competitive racers seeking every possible advantage in speed and aerodynamics. It's particularly well-suited for flat to rolling terrain, fast group rides, and riders prioritizing performance over versatility.
References
[1] - https://playtristore.com/products/cervelo-s5-shimano-ultegra-di2-12-speed?srsltid=AfmBOop-l_rMrsybj3gq0kcEs2OzzjHc6sTtDaMAW8vVZ4mipcgNAVLM
[2] - https://www.excelsports.com/cervelo-s5-ultegra-di2-bicycle-2023?srsltid=AfmBOopUPNtbpWx6dWjwEMlc1kC9s4XYwvnF-JHYJGc2i6NDpPvuh2v8
[3] - https://www.excelsports.com/cervelo-s5-ultegra-r8170-di2-bicycle-2025?srsltid=AfmBOopDXAn6_bYUP4pfN8F0aqbYIUCGMVTtZCyYVuV5rAGH_Dz59XTJ
[4] - https://www.cervelo.com/en-US/bikes/s5
[5] - https://99spokes.com/bikes/cervelo/2023/s5-ultegra-di2
[6] - https://reservewheels.com/products/reserve-52-63-road-wheel
[7] - https://granfondo-cycling.com/cervelo-s5-2023-aero-bike-review/
[8] - https://www.excelsports.com/cervelo-s5-ultegra-di2-bicycle-2023?srsltid=AfmBOopiK9bcGXd5njnuuvDBFteGEUYR2PXIq5WrY0debbGX8nwSS73X
[9] - https://99spokes.com/en/bikes/cervelo/2023/s5-ultegra-di2?nxtPmakerId=cervelo&nxtPyear=2023&nxtPmodelId=s5-ultegra-di2
[10] - https://cyclingtips.com/2022/12/cervelo-s5-review-a-truly-exhilarating-superbike/
[11] - https://road.cc/content/review/262990-cervelo-s5-ultegra-di2-disk
[12] - https://bikerumor.com/long-term-review-cervelo-s5-aero-road-bike/
[13] - https://weightweenies.starbike.com/forum/viewtopic.php?t=170124&start=315
[14] - https://www.youtube.com/watch?v=lO1cb__VxWo
[15] - https://road.cc/content/feature/which-tour-de-france-superbike-best-302181
[16] - https://bikotic.com/SHOOTOUTS/CERVELO_S5_DURA_ACE_DI2_VS_CERVELO_R5_DURA_ACE_DI2.html
[17] - https://99spokes.com/compare?bikes=cervelo-s5-dura-ace-di2-2024%2Ccervelo-s5-ultegra-di2-2024
[18] - https://www.cyclingnews.com/reviews/cervelo-s5-review-2025/