ULTRON S3 rear
BUILT FOR KONA.
When a disc wheel is not an option, the ULTRON S3 REAR is.
On courses such as Kona, where full rear disc wheels are not permitted, S3 REAR offers a highly aerodynamic alternative — combining three wide carbon spokes with the deep 85–95mm OCT Aero profile.
In stock
World wide shipping in 3-10 days
WORLD-CHAMPIONSHIP SPEED WITHOUT A DISC.
The ULTRON S3 REAR fills the gap between a conventional deep-section wheel and a full disc.
Its three wide aerodynamic spokes and variable-depth OCT Aero rim create a large aerodynamic surface while maintaining a wheel configuration suitable for races where discs are restricted.
From Kona to other disc-restricted courses, S3 gives athletes another way to race at the highest level.
PROVEN IN KONA. BUILT TO GO FAST EVERYWHERE.
Three spokes. Purpose in every profile.
The distinctive shape of S3 reflects its purpose. Three wide, wing-shaped spokes connect the hub to the rim, creating a stiff carbon structure.
Their geometry was developed to reduce aerodynamic drag and make use of airflow at crosswind angles. Every detail matters, from each spoke’s cross-section to the way it meets the rim and hub.
Eight concepts. One final geometry.
During development, we tested eight different spoke concepts. The final design was selected with aerodynamics and sailing effect in mind — two important considerations for a wheel built for triathlon and time trial racing.
OCT Aero. A profile with changing depth.
The ULTRON S3 rim varies in depth from 85 to 95 mm. Its wave-shaped profile builds on the rim technology used in ULTRON 85 and ULTRON 105, bringing it into a three-spoke construction.
On the road, airflow rarely arrives directly from the front. Wind direction, riding speed and changes in the course continuously affect the angle at which air meets the wheel.
OCT Aero was developed with these changing airflow conditions in mind. Variable rim depth works alongside the wide profile and spoke geometry as part of the complete wheel design.
85–95 mm of depth. Engineered with real riding conditions in mind.
A wide platform for modern tyres
ULTRON S3 features a 24 mm internal rim width and a profile measuring up to 34 mm at its widest point. It is designed around 28–30 mm tyres.
Internal rim width influences how a tyre sits on the wheel and its inflated shape. It also forms part of the setup when choosing pressure for your system weight, tyre model and road surface.
For the rider, this means an opportunity to fine-tune the complete combination of wheel, tyre and pressure — the elements that influence comfort, grip and rolling resistance.
Designed around 28–30 mm tyres.
When choosing your tyres, check their actual inflated width and the available clearance in your fork.
Harness the potential of crosswinds
Crosswinds change the way air flows around a wheel. At suitable angles, an aerodynamic profile can generate a force with a forward component. This phenomenon is known as the sailing effect.
ULTRON S3 was developed with this effect in mind. Its wide spokes and deep rim create aerodynamic surfaces shaped to work with airflow arriving from the side as well as the front.
The effect depends on riding speed, wind speed and wind angle. It is an opportunity to gain aerodynamic efficiency under suitable conditions, rather than a constant benefit in every situation.
Product specification
1020g
24 mm
31 mm
34 mm
28–30 mm
Hooked tubeless/ clincher
Disc brakes- centerlock mount
12x142 mm thru axle
2 × Enduro Ceramic
What’s Included
30
DAYS FREE RETURN
2
YEARS INTERNATIONAL WARRANTY
THE FASTEST AGE-GROUP BIKE SPLIT IN KONA 2026.
Lars Wichert — 4:25:26.
At the 2026 IRONMAN World Championship in Kona, Lars Wichert recorded a 4:25:26 bike split riding the ULTRON S3 setup.
The result demonstrates exactly what the S3 was created for: world-class aerodynamic performance on courses where a rear disc wheel cannot be used.
4:25:26 BIKE SPLIT
KONA WORLD CHAMPIONSHIP 2026
ULTRON S3 AERO SETUP
FAQ
Find answers to common questions about our products, orders, shipping, and support.
Can i return my order?
Yes, we offer 30-DAY SATISFACTION GUARANTEE – you can return your order for free.
Do RON ship international?
Yes, we ship all over the world with DHL Express.
Shipping costs will apply, and will be added at checkout.
How long will it take to get my orders?
If your wheels are in stock we aim to have them shipped within 1-3 days. Shipping takes 3-10 days.
Taxes and import duties
All shipments out of EU will incur duties and taxes charged to the end customer via DHL.
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