Easton EC90SL: The Ultimate Carbon Clincher?

When considering a high-performance bicycle wheelset, particularly one crafted from carbon fibre, several factors immediately come to the forefront of a discerning rider's mind: weight, stiffness, aerodynamics, durability, and crucially, braking performance. For a long time, carbon clincher wheels were often viewed with a degree of scepticism, primarily due to concerns surrounding heat build-up during braking, which could lead to reduced performance or, in extreme cases, catastrophic failure. However, Easton has been a brand consistently pushing the boundaries, and their EC90SL carbon clincher wheelset is a testament to this dedication. This article delves into what makes the EC90SL stand out, addressing its compatibility, technical innovations, and its position in the market.

What is the Easton EC90 ACC?

Before we dive into the EC90SL, it's worth noting the broader context of Easton's EC90 range. The Easton® EC90 ACC, for instance, features a full carbon sole designed to offer the stiffness required for everything from demanding Grand Tours to challenging gran fondos. Its ultra-low 6.5mm stack height promotes a direct connection to the pedals, enhancing power transfer. Furthermore, the inclusion of an adjustable SuperNatural Fit footbed allows riders to fine-tune their fit and arch support, aiming for an unparalleled blend of performance and comfort. This indicates a brand-wide commitment to high-performance cycling components.

Is the Easton EC90SL the Best Carbon Clincher?

The question of whether the Easton EC90SL is the *best* carbon clincher is a subjective one, but the evidence strongly suggests it's a leading contender. The core innovation lies in Easton's ThermaTec coating, a proprietary material moulded directly onto the rims. This coating is engineered to dissipate braking heat far more effectively than traditional carbon clincher designs. This is a critical advancement, as heat build-up has historically been the Achilles' heel of carbon clinchers.

James Huang, a renowned cycling journalist, highlights that the EC90SL clincher rim is not only built to handle braking heat but also allows for the use of external nipples. This design choice, while perhaps a slight compromise on ultimate aerodynamics, significantly enhances user-friendliness for maintenance. The wheelset also features Easton's R4SL hubs, which offer versatility with four freehub options: Shimano 10-speed, Shimano 8/9/10, SRAM Red only, and Campagnolo. These hubs are equipped with Grade 3 ceramic bearings as standard, front and rear, contributing to smooth rolling performance.

Addressing the Heat Issue: Easton's Six-Year Journey

Easton's approach to developing a no-compromise carbon clincher was a lengthy and meticulous process. They recognised that a viable carbon clincher had to overcome the heat-related issues that plagued earlier iterations from various manufacturers. These issues ranged from accelerated brake pad wear and compromised braking control to, in the worst-case scenarios, rim sidewall failures. Easton's commitment to solving this problem spanned six years, evolving from hybrid carbon and aluminium designs to the all-carbon EC90SL.

The breakthrough came with the development of a specific carbon laminate combined with the aforementioned ThermaTec heat dispersion coating. The result, as demonstrated in extensive field testing, is a wheelset that exhibits zero issues with heat, even under prolonged and demanding braking conditions, such as those encountered on steep, mountainous descents. Easton's goal was to create a carbon clincher that could be ridden without compromise, and based on performance data, they appear to have succeeded.

Field Testing: Pushing the Limits

To validate their claims, Easton put the EC90SL clinchers through rigorous field tests. One notable testing scenario involved a four-month period in Colorado, from December to March, a time when conditions could be challenging. The test route was a demanding five-mile out-and-back climb followed by a technical descent featuring numerous switchbacks. Speeds on the descent ranged from slow, controlled cornering to rapid 40mph tucks.

Initial rides involved cautious braking, gradually increasing the duration and intensity to monitor rim temperatures. This iterative process confirmed that even when braking for extended periods, the EC90SLs maintained significantly lower temperatures than other carbon wheels tested, including both clinchers and tubulars. Over 20 descents of the test course, equating to over 40,000 feet of descending, yielded no problems, instilling significant confidence in the wheelset's capabilities. This real-world testing provided concrete evidence of the ThermaTec coating's effectiveness.

Braking Performance: Modulation and Wet Conditions

The ThermaTec coating not only manages heat but also contributes to exceptional braking performance. The EC90SLs are noted for their excellent modulation, allowing riders to control braking power with precision. This performance is further enhanced by the use of SwissStop's Yellow King brake pads, which Easton includes as standard. These pads are specifically designed to work optimally with carbon braking surfaces.

However, it's important to note that while braking power in dry conditions is excellent, it remains slightly lower compared to traditional alloy rims. In wet conditions, the performance is adequate but requires an adjustment in braking distances. The water that can accumulate on the rim surface needs to be displaced by the brake pads before effective braking can occur. Despite this, the rims maintain their ability to modulate power effectively, even when wet.

Stiffness and Handling

In terms of stiffness, the EC90SLs perform admirably. They offer predictable handling during hard cornering and strenuous climbing efforts. Lateral stiffness was also put to the test, with attempts to induce flex or instability during hard sprints proving futile. For lighter riders and those who aren't aggressive sprinters, the wheels are considered exceptionally solid and stiff. Vertical compliance is on the lower side, meaning larger impacts can feel more pronounced. However, on rougher surfaces like washboard dirt roads, the wheels seemed to absorb some of the vibration, offering a surprisingly compliant ride in certain situations.

Hubs and Durability

During testing, a bent spoke was encountered, which predictably pulled the wheel out of true. Crucially, the rim itself did not fail and was easily trued. This highlights the inherent durability of the carbon rim structure. Easton's R4SL hubs, while generally reliable, did exhibit some quirks. In cold temperatures (below 40°F or 4°C), the freehub mechanism could become sluggish due to the viscosity of the grease. This occasionally led to minor chain derailments, particularly during backpedalling, though this issue was not present in warmer temperatures. Easton does offer lighter grease for riders who frequently encounter cold conditions.

Freehub engagement was consistent and solid, with an average engagement speed. Over the course of the testing period, both the front and rear hubs required adjustment, with the rear hub needing attention three times and the front once. While not a deal-breaker, this indicates that regular maintenance checks are advisable.

Easton's Solution to the Heat Problem: A Deeper Dive

Adam Marriott, Easton's wheel product manager, elaborated on the development process. He recounted how early hybrid carbon wheels, when tested by professional teams like Astana, failed due to heat, leading Easton to halt the launch and reassess. This spurred the development of a more robust testing protocol. Engineers created a simulation involving a rider carrying extra weight, descending a hill with the front brake applied, forcing them to pedal intensely to maintain speed, replicating the failure conditions experienced by pros.

By incorporating thermocouples and infrared sensors, Easton gathered crucial data on temperature build-up. This information allowed them to develop a standardised lab test that accurately replicates real-world stresses. Marriott explained that this testing allowed them to analyse their own wheels, competitor offerings, and aluminium wheels, identifying strengths and weaknesses. The outcome was a hybrid wheel that has performed without issue for four years and, more importantly, the development of a carbon laminate designed to draw heat through the system, coupled with the ThermaTec coating for heat management. Easton's testing indicated that only one other competitor's wheel was still rideable after their rigorous heat tests, underscoring the effectiveness of Easton's solution.

Weight, Price, and Durability: The Trade-offs

While the EC90SLs excel in many areas, potential buyers must consider the trade-offs, primarily concerning weight and price. The 38mm-tall EC90SL clincher wheelset weighs approximately 1,506g (actual weight), which is heavier than comparable tubular wheelsets like Easton's own EC90SL tub (1,224g). Marriott explained that achieving the same weight as tubulars with clinchers necessitates a stronger structure to withstand heat, hence the weight difference.

For comparison, Easton's EA90SLX aluminium wheelset (21mm front, 24mm rear) weighs a claimed 1,398g, while the EA90Aero aluminium set (28mm front, 32mm rear) weighs 1,603g. The aerodynamic advantage of the 38mm EC90SL rim over these alloy options is difficult to quantify without wind tunnel data, but it's likely to be a factor at higher speeds.

The price is another significant consideration. At approximately £1,449.99 ($1,799), the EC90SL carbon clincher wheelset is considerably more expensive than comparable alloy offerings from Easton. However, this higher price point is partially justified by the wheelset's durability. The carbon rim is robust, arguably overbuilt compared to the tubular version, and designed for longevity. Unlike metal rims that can bend or dent, carbon rims are generally either perfect or broken; there's little in-between. If a spoke breaks or bends on the EC90SL, and the rim remains intact, it's usually possible to replace the spoke and true the wheel back to its original state. Easton's testing suggests the carbon rim can withstand impacts magnitudes higher than their alloy counterparts.

Nipples: External vs. Internal

A point of contention for some is the use of external nipples on the EC90SL, which are more user-friendly for spoke maintenance. Easton opts for internal nipples on their tubular wheels. The rationale provided by Easton is that tubular rims would require significant reinforcement to support external nipples, leading to a heavier rim. For the EC90SL clincher, the choice was made to use a lighter rim construction and external nipples for ease of maintenance, a practical decision given the clincher design.

Final Verdict: A Top-Tier Carbon Clincher

In conclusion, Easton's EC90SL stands out as an exceptional carbon clincher wheelset, arguably the best available on the market for riders seeking this specific technology. Its revolutionary approach to heat management, combined with excellent braking modulation, stiffness, and user-friendly external nipples, addresses the historical shortcomings of carbon clinchers. While the weight and price are higher than some alternatives, the durability and performance benefits are substantial.

The ideal evolution for this wheelset would be a reduction in weight and the integration of tubeless compatibility, which would undoubtedly solidify its position as a five-star product. However, as it stands, the EC90SL is a wheelset that inspires confidence. For the discerning rider who desires a carbon clincher without performance compromise, the EC90SL represents a leading, if not the definitive, option currently available.

Frequently Asked Questions

Q1: Is the Easton EC90SL compatible with my bike?
The Easton EC90SL is designed to fit standard road bike frames with the correct axle spacing and hub compatibility. It comes with options for Shimano (8/9/10, 10-speed) and Campagnolo freehubs, so ensure your drivetrain cassette is compatible with the chosen freehub body. Always check your frame's dropout spacing and ensure it matches the hub's specifications.

Q2: How does the ThermaTec coating work?
The ThermaTec coating is a special material moulded onto the rim's braking surface. Its primary function is to absorb and dissipate heat generated by braking friction more effectively than standard carbon composites, preventing overheating and maintaining braking performance and structural integrity.

Q3: Are the EC90SLs good for climbing?
Yes, the EC90SLs are known for their stiffness, which translates well to climbing. Their predictable handling and efficient power transfer allow riders to put down power effectively when ascending gradients.

Q4: How do they perform in wet conditions?
In wet conditions, braking power is adequate but slightly reduced compared to dry conditions. Riders may need to allow for longer braking distances as water needs to be cleared from the rim surface. However, the modulation of braking power remains good.

Q5: What is the main advantage of the EC90SL over other carbon clinchers?
The primary advantage is Easton's innovative solution to heat management through the ThermaTec coating and specific carbon laminate, which significantly reduces the risk of overheating and rim failure, a common issue with earlier carbon clinchers. They also offer excellent braking modulation.

Q6: Are these wheels suitable for everyday riding or just racing?
While they are high-performance wheels suitable for racing, their durability and improved heat management make them a viable option for serious everyday riding, especially for those who tackle challenging terrain with frequent descents.

Q7: Can I use different brake pads with the EC90SL?
Easton includes SwissStop Yellow King brake pads, which are optimised for these wheels. While other carbon-specific brake pads might work, using the recommended pads ensures the best performance and safety. Always consult Easton's recommendations or a qualified bike mechanic.