Enduro Revolution: How the Actofive P-Train MK2’s Variable High Pivot Design Redefines Mountain Bike Suspension

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Enduro racing demands frames that can handle everything from technical climbs to World Cup descents, and the Actofive P-Train MK2 delivers with its variable high pivot suspension platform offering four distinct travel configurations from 145mm to 175mm.

Variable High Pivot Suspension Architecture: The Engineering Behind 145-175mm Travel Options

The P-Train MK2’s variable high pivot point (HPP) suspension design represents a significant evolution in mountain bike kinematics. Unlike traditional suspension layouts, the elevated main pivot location fundamentally alters the rear wheel’s axle path during compression, creating a rearward trajectory that effectively lengthens the bike’s wheelbase under load. This rearward axle movement allows the rear wheel to move backward and upward when encountering obstacles, reducing the impact forces transmitted to the rider. To maintain this sophisticated system, many riders rely on the Park Tool HPG-1 High Performance Grease for pivot maintenance, ensuring smooth operation and longevity of the suspension bearings under extreme conditions.

The single downtube bottle mount on the topside maintains hydration capability despite the frame’s complex suspension architecture. This placement keeps weight low and central while remaining accessible during rides. The maximum tire clearance accommodates up to 29×2.5-inch rubber, providing traction and cushioning for technical terrain without compromising mud clearance or adding unnecessary rotational weight.

This progression from experimental trail bike to World Series-proven enduro race machine demonstrates the P-Train MK2’s versatility. Whether configured as a 145mm trail crusher or a 175mm park destroyer, the platform delivers the progressive geometry, sophisticated suspension, and bombproof construction that modern mountain biking demands. The ability to reconfigure travel and geometry means a single frame can adapt as skills progress, terrain changes, or racing goals evolve—making it a compelling investment for serious riders seeking long-term performance.  The OneUp Components Dropper Post V3 provides the perfect complement to the frame’s aggressive geometry, offering reliable seat height adjustment for technical climbs and committed descents.

CNC-Machined 7075-T6 Aluminum Construction: Two-Piece Hollow Bonded Frame Technology

Actofive’s approach to frame construction diverges from conventional welded or molded designs. Each P-Train MK2 frame begins as solid blocks of 7075-T6 aluminum, an aerospace-grade alloy known for its exceptional strength-to-weight ratio and fatigue resistance. The CNC machining process removes material with precision tolerances measured in hundredths of millimeters, creating a two-piece hollow structure that maximizes stiffness while minimizing mass.

The two-piece design splits the front triangle into strategically engineered halves, which are then permanently joined using structural adhesive bonding. This construction method eliminates the heat-affected zones associated with welding, preserving the aluminum’s temper and mechanical properties throughout the structure. The bonded interface distributes loads across a larger surface area compared to welded joints, reducing stress concentrations and improving long-term durability. To protect this precision-engineered frame during transport or storage, many owners invest in the EVOC Bike Travel Bag Pro, which provides dedicated protection for high-end mountain bikes with its reinforced padding and wheel compartments. 

The hollow internal structure serves multiple purposes beyond weight reduction. Internal cable routing channels are precisely machined into the frame during the CNC process, allowing for clean aesthetics and protected cable runs. The frame tips the scales at 4,300 grams for a size S2 without shock—competitive for a long-travel aluminum frame with this level of adjustability and robustness. The finish options include raw aluminum or nine anodized colorways, with the anodizing process providing both aesthetic appeal and additional surface protection against corrosion and wear.

ADJUSTABLE RIDE° Geometry System: Customizable BB Height, Head Angle, and Chain stay Configuration

The ADJUSTABLE RIDE° (AR°) concept transforms the P-Train MK2 from a single-geometry frame into a highly adaptable platform. This system allows riders to fine-tune five critical geometry parameters: bottom bracket height, rear travel, wheel size configuration (including mullet compatibility), chain stay length, and head angle. These adjustments don’t require frame modifications or replacement parts—they’re built into the design through flip chips, adjustable dropouts, and shock stroke adjustments.

The baseline geometry starts aggressive with a 64-degree head angle and a steep 78-degree seat angle. The slack head angle provides stability at high speeds and confidence on steep descents, while the steep seat angle positions riders efficiently for technical climbing. The effective seat angle remains consistent throughout the suspension travel thanks to the high pivot design, maintaining optimal pedaling position even deep into the travel.  To dial in these geometry adjustments precisely, the Park Tool DAG-2.2 Digital Angle Gauge proves invaluable for measuring and verifying head and seat angles when experimenting with the frame’s ADJUSTABLE RIDE° settings.

Chain stay length adjustability accommodates different riding styles and terrain preferences. Shorter chain stays enhance maneuverability and facilitate manual-based techniques, while longer settings improve high-speed stability and weight distribution for steep descents. The mullet-ready design accepts 29-inch wheels front and rear or a mixed 29-inch front with 27.5-inch rear configuration, further expanding the geometry tuning options. Size options span S1, S2, and S3, with maximum seatpost insertion depths of 215mm, 235mm, and 265mm respectively, ensuring proper fit across a wide range of rider heights.

SRAM UDH and Transmission Integration: Modern Drivetrain Compatibility with Floating Brake Options

The MK2 incorporates SRAM’s Universal Derailleur Hanger (UDH) standard, future-proofing the frame for current and upcoming drivetrain technologies. The UDH system provides a robust, replaceable interface that’s consistent across manufacturers, simplifying maintenance and replacement parts sourcing. More significantly, the frame is fully Transmission-ready, compatible with SRAM’s latest direct-mount derailleur system that eliminates the traditional hanger altogether for improved shifting precision under load.

The optional floating brake mount represents sophisticated engineering to combat brake jack—the tendency for rear brake forces to extend the suspension during braking. The floating brake system decouples braking forces from suspension movement, allowing the rear wheel to track terrain independently of brake application. When equipped with the floating brake, the frame accepts PM 200mm rotors; the fixed brake configuration runs PM 180mm standards.  For either configuration, the SRAM HS2 Rotor delivers exceptional heat management and consistent braking performance, with the 200mm option perfectly suited for the floating brake setup’s demands during aggressive descending.

Cable routing flexibility acknowledges diverse build preferences and maintenance requirements. Riders can choose full internal routing for clean aesthetics and cable protection, external routing for simplified maintenance, or a mixed approach optimizing both concerns. The frame includes ISCG 05 tabs for chain guide mounting, essential for aggressive riding where chain retention becomes critical. The 73mm threaded BSA bottom bracket shell ensures compatibility with a wide range of cranksets while providing reliable, creak-free performance.

Race-Proven Development: From 135mm Trail Origins to EWS-Tested 175mm Enduro Platform

The P-Train’s evolution from its 2020 debut as a 135mm trail bike to today’s 175mm race weapon illustrates Actofive’s commitment to iterative development. The original P-Train CNC pioneered the high pivot concept in the trail bike category when such designs were primarily reserved for downhill applications. This early adoption provided valuable data on suspension behavior across varied terrain and riding styles.

The 2022 season marked a pivotal development phase when Vojtěch Bláha campaigned the P-Train in the Enduro World Series. Racing at the sport’s highest level exposed the frame to extreme conditions—from liaison stage sprints to timed descents that would destroy lesser equipment. The telemetry data, rider feedback, and mechanical stress testing from this campaign directly influenced the MK2’s refinements. Suspension kinematics were adjusted to improve small-bump sensitivity while maintaining mid-stroke support. Frame stiffness was optimized through FEA analysis to handle the lateral loads generated during flat-out cornering, particularly when running aggressive tires like the Maxxis Assegai 29×2.5 WT, which World Series racers favor for its cornering grip and sidewall support during high-speed compressions.

The single downtube bottle mount on the topside maintains hydration capability despite the frame’s complex suspension architecture. This placement keeps weight low and central while remaining accessible during rides. The maximum tire clearance accommodates up to 29×2.5-inch rubber, providing traction and cushioning for technical terrain without compromising mud clearance or adding unnecessary rotational weight.  For optimal hydration during long enduro stages, the Fidlock TWIST Bottle 600 magnetic mounting system works exceptionally well with the P-Train’s downtube placement, offering secure retention over rough terrain while allowing quick, one-handed bottle removal.

This progression from experimental trail bike to World Series-proven enduro race machine demonstrates the P-Train MK2’s versatility. Whether configured as a 145mm trail crusher or a 175mm park destroyer, the platform delivers the progressive geometry, sophisticated suspension, and bombproof construction that modern mountain biking demands. The ability to reconfigure travel and geometry means a single frame can adapt as skills progress, terrain changes, or racing goals evolve—making it a compelling investment for serious riders seeking long-term performance.

BUILDING YOUR ENDURO MACHINE? HERE ARE THE ESSENTIAL UPGRADES FOR YOUR P-TRAIN MK2!

The Must-Have Components for Maximum Performance:

✅ RockShox ZEB Ultimate Fork 180mm The perfect high-pivot companion for aggressive enduro riding ⭐⭐⭐⭐⭐ 4.7/5 (892 reviews) [Check Price on Amazon →]

✅ Fox Float X2 Factory Shock Premium air shock for unmatched adjustability and control ⭐⭐⭐⭐⭐ 4.8/5 (567 reviews) [Check Price on Amazon →]

✅ SRAM GX Eagle AXS Transmission Groupset Wireless shifting perfection for your UDH-ready frame ⭐⭐⭐⭐⭐ 4.6/5 (1,423 reviews) [Check Price on Amazon →]

✅ DT Swiss EX 1700 Spline Wheelset Bombproof wheels built for enduro punishment ⭐⭐⭐⭐⭐ 4.5/5 (738 reviews) [Check Price on Amazon →]

✅ PNW Loam Dropper Post 200mm Maximum drop for steep descents and technical climbs ⭐⭐⭐⭐⭐ 4.7/5 (2,156 reviews) [Check Price on Amazon →]