The TIME ATAC XC 2 [paid link] pedals and the Shimano SPD M520 are both popular choices among cross-country and gravel riders seeking durable, clip-in pedal systems for all-weather reliability. However, while they serve a similar purpose, the design philosophy, engagement mechanism, and long-term performance differ significantly between the two. This guide provides an expert-level [paid link] comparison to help riders make an informed decision when choosing between these two renowned pedal models.
Design and Construction
The ATAC XC 2 [paid link] pedals feature TIME’s distinctive Auto Tension Adjustment Concept (ATAC) mechanism, known for its self-cleaning engagement system and generous float range. The composite body reduces weight while maintaining stiffness, making it a strong entry-level [paid link] model for competitive cross-country use.
In contrast, the Shimano SPD M520 uses a dual-sided steel retention system with an aluminum body and chromoly spindle. The design prioritizes proven durability and a predictable feel underfoot. While heavier than the ATAC XC 2, the SPD M520 has a reputation for withstanding years of rugged use with minimal wear.
Where TIME emphasizes biomechanical freedom and mud-shedding ability, Shimano prioritizes tight engagement and longevity under load.
Engagement and Float Mechanism
The most noticeable difference lies in how each pedal engages and releases the cleat. TIME’s ATAC mechanism provides a self-cleaning interface that ejects mud and debris automatically as you clip in. The engagement angle is broad and forgiving, allowing easy entry even in challenging trail conditions. The ATAC XC 2 offers ±5° of angular float and 6 mm of lateral float, which helps reduce knee strain and allows a natural pedaling motion.
Shimano’s SPD M520, on the other hand, offers a tighter engagement feel with adjustable release tension. It provides 4° of float, slightly less than the ATAC XC 2. Riders who prefer a firm, locked-in sensation during sprints or climbs often gravitate toward the SPD design. However, it can feel restrictive to riders seeking a more fluid pedaling motion.
Weight and Efficiency
Weight plays a critical role for cross-country riders aiming to minimize rotational mass. The ATAC XC 2 pedals weigh approximately 151 grams per pedal, while the Shimano SPD M520 comes in at around 185 grams per pedal.
This 30–35 gram difference per pedal may seem small but can influence acceleration responsiveness and climbing efficiency. TIME’s minimalist composite body design achieves lower weight without compromising pedal stiffness, giving it a slight advantage for riders focused on racing or long-distance performance.
Maintenance and Durability
Maintenance requirements differ significantly between the two systems. The ATAC XC 2 features a sealed steel bearing and bushing system that resists contamination. Its open architecture prevents mud buildup, minimizing the need for frequent cleaning or relubrication. Routine inspection of the spring and engagement mechanism ensures optimal longevity.
Shimano’s SPD M520 pedals use cup-and-cone bearings, which require periodic adjustment and greasing. This design allows for complete serviceability, but it also means more frequent maintenance intervals, especially in wet or muddy conditions. For riders comfortable with mechanical upkeep, the SPD’s serviceable bearings may extend lifespan.
Overall, the ATAC XC 2 offers lower maintenance demands, making it appealing for riders who prefer a “fit and forget” system.
Mud Shedding and Off-Road Performance
The ATAC XC 2’s self-cleaning mechanism is its standout advantage in off-road conditions. TIME engineered the retention system to expel mud automatically, which maintains consistent engagement even in sticky or clay-heavy terrain. Riders who frequently encounter wet trails, cyclocross conditions, or gravel events benefit from this superior debris management.
Shimano’s SPD M520, although reliable, can accumulate mud and require manual clearing before clipping in. While its spring tension can be loosened to aid entry, it rarely matches TIME’s automatic self-cleaning efficiency.
Cleat Design and Compatibility
The ATAC XC 2 uses TIME’s proprietary ATAC cleats [paid link], which provide generous float and are made from brass for improved wear resistance. Cleat setup is straightforward, and replacement cleats are widely available. However, these cleats are not cross-compatible with SPD shoes or pedals.
Shimano’s SPD cleats are the industry standard, compatible with a wide range of cycling shoes and pedal systems from multiple brands. This universality makes them easier to replace and ideal for riders with multiple bikes using SPD-compatible pedals.
For riders prioritizing freedom of movement and knee comfort, the TIME cleat system offers a clear advantage. For those valuing universal compatibility, Shimano’s SPD system remains more practical.
Ride Feel and Pedaling Dynamics
Riders often describe the ATAC XC 2 as offering a natural, fluid pedaling sensation. The combination of lateral float and flexible engagement promotes smooth power delivery, especially over uneven terrain. The forgiving entry and release motion also make the pedal ideal for long rides where comfort is paramount.
In contrast, the SPD M520 provides a snappier, more mechanical feel. The engagement is crisp and definitive, ideal for riders who prioritize direct power transfer and a locked-in pedaling platform. This characteristic benefits aggressive riders who prefer precision and minimal pedal movement during sprints or technical climbs.
Customization and Adjustment
The ATAC XC 2 pedals do not include adjustable release tension, as the ATAC mechanism automatically adapts to the rider’s cleat position and wear. While this limits customization, it also eliminates setup errors and ensures consistent release tension throughout the pedal’s lifespan.
Shimano’s SPD M520 features a manual tension adjustment screw on each side of the pedal, allowing fine-tuning of engagement resistance. This flexibility lets riders modify the pedal’s feel based on terrain, shoe stiffness, or personal preference.
For cyclists who appreciate simplicity and consistent performance, the ATAC XC 2’s auto-adjusting system excels. Those who prefer full control over engagement force may find the SPD M520 more suitable.
Price and Value
Both models fall within the budget-friendly segment of clip-in pedal systems. The ATAC XC 2 typically retails slightly higher than the SPD M520 due to its lighter construction and self-cleaning design. However, the maintenance savings and improved float mechanics may offset the initial cost over time.
Shimano’s SPD M520 offers exceptional long-term value through robust serviceability and widespread parts availability. For riders prioritizing affordability and proven reliability, the SPD M520 remains a strong choice.
Final Verdict: Which Pedal Should You Choose?
The TIME ATAC XC 2 and Shimano SPD M520 both deliver dependable performance, but they cater to different rider priorities.
- Choose the TIME ATAC XC 2 if you value:
- Lightweight construction
- Superior mud clearance
- Increased float and knee comfort
- Minimal maintenance requirements
- Choose the Shimano SPD M520 if you prefer:
- Adjustable tension control
- Universal cleat compatibility
- Maximum durability and serviceability
- A firmer, locked-in pedal feel
For riders who spend long hours on unpredictable terrain, the ATAC XC 2’s self-cleaning design and forgiving engagement make it the more technically advanced option. However, for riders who prioritize durability, adjustability, and cost-effectiveness, the SPD M520 remains a benchmark of reliability.
Ultimately, your choice should align with your riding style and maintenance preferences. Both pedals represent the pinnacle of their respective design philosophies—TIME focusing on ergonomic performance, and Shimano emphasizing enduring dependability.