Swiss Side Hadron Ultimate 625: An F1 Engineer’s Carbon Wheel Masterpiece

When an aerodynamicist who once worked with the Sauber F1 team decides to dedicate himself to bicycle wheel design, what kind of product emerges? The answer is Swiss Side. Founded by Jean-Paul Ballard, this Swiss brand brings Formula 1 aerodynamic analysis methods and Computational Fluid Dynamics (CFD) technology into carbon wheel design, and the Hadron Ultimate 625 is the finest embodiment of this F1 DNA.

Product Specifications

Item	Specification
Rim Depth	62.5mm
External Rim Width	29mm
Internal Rim Width	20mm
Weight (Front + Rear)	1,495g (Disc Brake Version)
Hubs	DT Swiss 240 EXP
Engagement Mechanism	Ratchet EXP 36T
Spokes	Sapim CX-Ray
Spoke Count	Front 18 / Rear 24
Tire Compatibility	Tubeless Ready (Hooked Rim)
Suggested Retail Price	NT$65,000-80,000

Transferring F1 Aerodynamic Technology

CFD Computational Fluid Dynamics

Swiss Side relies heavily on CFD simulations to optimize wheel design rather than simply depending on wind tunnel testing. F1-grade CFD analysis can simulate thousands of combinations of wind speeds, yaw angles, and riding positions to identify the most optimized rim profile under real-world riding conditions.

Boundary Layer Management

Drawing on aerodynamic design experience from F1 racing, Swiss Side places particular emphasis on “boundary layer management” in the rim profile design of the Hadron Ultimate—keeping airflow laminar for as long as possible and delaying the onset of turbulence. This is technically more complex than simply pursuing minimal cross-sectional area, but the results are also far more significant.

Real-World Aerodynamic Optimization

Swiss Side’s design philosophy places special emphasis on “real-world” aerodynamic performance rather than merely chasing the best figures at 0 degrees of yaw in a wind tunnel. They argue that in actual riding environments, yaw angles between 5-15 degrees account for the majority of the time, so the design should prioritize optimization for this range.

The Positioning of the 62.5mm Rim Depth

The 62.5mm rim depth of the Hadron Ultimate 625 sits at the intersection of aerodynamics and versatility. This depth provides significant aerodynamic advantages while avoiding the handling difficulties in crosswinds that plague ultra-deep wheels of 80mm+.

Swiss Side’s Product Line Logic

Swiss Side offers multiple rim depth options:

Model	Rim Depth	Positioning
Hadron Ultimate 400	40mm	All-Rounder / Climbing
Hadron Ultimate 500	50mm	All-Rounder
Hadron Ultimate 625	62.5mm	Aero / All-Rounder
Hadron Ultimate 800	80mm	Time Trial / Triathlon

The 625 is the most popular “sweet spot”—enough aerodynamic advantage while maintaining good handling.

The Choice of DT Swiss 240 Hubs

Swiss Side’s decision to pair the wheels with DT Swiss 240 EXP hubs is a very rational one. The 240 hub’s reputation and reliability in the industry need no introduction, and the maintainability and upgradeability of the Ratchet EXP system are added bonuses.

For a relatively niche brand, choosing a proven top-tier hub rather than manufacturing their own ensures convenience for consumers when it comes to after-sales maintenance.

Swiss Side’s Testing Culture

Swiss Side is renowned for its transparent testing data and methodology. They publish complete wind tunnel test conditions and results, and even make comparison data against competitors publicly available on their website. This level of transparency is quite rare in the carbon wheel industry and reflects the rigorous approach of an engineer-led brand.

Real-World Riding Experience

Aerodynamic Performance

The aerodynamic advantage of the 62.5mm rim depth is very noticeable when cruising on flat roads. In the 35-50 km/h speed range, you can feel the Hadron Ultimate 625 “cutting through” the air with efficiency. Compared to carbon wheels in the 48mm class, it saves 3-5 watts at cruising power.

Crosswind Stability

Swiss Side’s engineering prowess in crosswind stability is impressive. The 62.5mm deep rim doesn’t cause unease under typical crosswind conditions, and the lift generated by the rim profile in crosswinds is effectively controlled.

Acceleration Response

At 1,495g, the weight is within the normal range for this rim depth. Acceleration response isn’t as snappy as lightweight carbon wheels, but once cruising speed is reached, the aerodynamic advantage comes into full play.

Suitability in Taiwan

The 62.5mm rim depth serves a fairly specific set of use cases in Taiwan—the West Coast Expressway, flat sections of island round-the-island routes, and criterium racing are its primary battlegrounds. On long climbing routes like Wuling, the heavier weight would be a disadvantage.

Pros and Cons Analysis

Pros

• F1-grade aerodynamic design and CFD analysis
• Transparent testing data and methodology
• DT Swiss 240 hubs are reliable and easy to maintain
• Hooked rim design offers excellent compatibility
• Competitive value among high-end aero carbon wheels
• Swiss brand quality assurance

Cons

• Brand awareness is relatively low
• Limited purchasing channels in Taiwan
• 62.5mm rim depth is not advantageous on Taiwan’s climbing routes
• 20mm internal rim width is on the narrower side
• 18 front spokes may lack stiffness during aggressive riding
• Weight is not an advantage in its class

Purchasing Advice for Taiwan

Purchasing Channels

• Swiss Side official website direct purchase (international shipping available)
• European bicycle parts websites (e.g., bike-components.de)
• A small number of professional bike shops in Taiwan that carry the brand

Who Is It For?

• Data-driven, engineer-type riders who value scientific validation
• Time trial and triathlon athletes
• Riders who frequently ride flat and rolling routes
• Tech enthusiasts who enjoy studying aerodynamic technology

Conclusion

The Swiss Side Hadron Ultimate 625 is a carbon wheelset imbued with engineering spirit. The transfer of F1 aerodynamic technology, transparent testing data, and the rational choice of DT Swiss 240 hubs make this wheelset an ideal choice for data-driven riders. In today’s carbon wheel market, which is saturated with marketing gimmicks, Swiss Side’s scientific approach and engineering rigor stand out as a breath of fresh air. If you believe in data and believe in science, the Hadron Ultimate 625 will not disappoint.

Related Reading

• Swiss Side Hadron: F1 Aerodynamics Applied to Bicycles
• The Complete Guide to DT Swiss Wheels: From the King of Hubs to Carbon Wheel Newcomers
• FFWD RYOT 55: The Dutch Handcrafted All-Rounder Race Wheel
• DT Swiss ARC 1100 DICUT: Swiss Precision Engineering in Aero Carbon Wheels