Mullet Compatibility

The Nighttrain 170mm frame supports a mullet wheel configuration: 29" front wheel paired with a 27.5" rear wheel. This configuration offers distinct advantages for technical terrain but requires specific component compatibility.

Geometry Changes with Mullet Setup

• Head Tube Angle: 62° (slacker than stock 63°)
• Seat Tube Angle: 76.5° (reduced from stock)
• Bottom Bracket Height: Reduced compared to standard configuration

Correction with Angleset Headset

To maintain stock geometry with a mullet setup, install a +1° angleset headset to bring the Head Tube angle back to 63° (stock).

Front Fork Compatibility

Travel	Offset	Compatibility
170mm	44mm offset	✓ Fully Compatible
160mm	44mm offset	✓ Fully Compatible
190mm Dual Crown	48mm offset	✓ Fully Compatible
200-203mm	Any	✗ NOT SUPPORTED

Rear Shock Compatibility

Compatible Brands:

• FOX: Float X2, Float X, DHX2
• Rockshox: Vivid, Vivid Coil

⚠️ NOT Compatible: Rockshox Super Deluxe

Rear Shock Sizing

Travel	Sizing
170mm travel	230×65mm
160mm travel	230×60mm

Shock Mounting Spacing

• Lower Mount: 10×40mm
• Upper Mount: 10×35mm with 40mm bushing

Bushing Kit Requirements

RMU 33.53/40 FOX Shock Spacing Kit includes:

• RMU spacer (ID 12.83mm / OD 19.05mm / thickness 0.81mm)
• FOX crush washer
• FOX O-ring + white bushings (10x33.53 kit)
• 10x40 FOX sleeve (included with frame, also sold separately)

RMU 35/40 FOX Shock Spacing Kit

Alternative shock spacing kit configuration for different setups.

Bottom Bracket

• Specification: 73mm BSA threaded (1.37" x 24tpi)
• Standard threaded bottom bracket compatibility

Crank Spindle

• Spindle Length: 130–136mm Boost
• Chainline: 55mm

Chainring Interfaces

The Nighttrain 170mm supports RMU-specific direct-mount chainrings only:

• RaceFace/SRAM 8-bolt pattern: Direct mount compatible
• Pivot 3-bolt pattern: Direct mount compatible

Integrated Crank Systems

• Hope cranksets: Fully compatible
• Hope Pivot-compatible chainrings: Fully compatible

Chain Specifications

• Idler Chain Length: 38 links (including quick link)

Brake Cable Routing

• Rear Brake: Internal routing with foam sleeve OR external Moto configuration available
• Foam sleeves recommended to prevent rattle

Derailleur & Dropper Cable Routing

• Configuration: Full internal routing
• Recommendation: Foam sleeves recommended to minimize rattle and cable noise

Seatpost Specifications

• Seatpost Diameter: 31.6mm
• Collar Diameter: 34.9mm

Rear Hub Thru-Axle

• Standard: 190×12mm
• Thread Pitch: 1.0mm

Rear Hub Spacing

• Spacing Standard: 12×157mm Superboost

Rear Disc Mount

• Thread Specification: M6 x 1.0

Derailleur Hanger

• Type: Universal Derailleur Hanger (UDH)

Important: Verify correct torque specifications before assembly. Over or under-torquing can affect suspension performance and frame integrity.

Component	Torque Value	Notes
Shock Lower Bolt	10 Nm	-
Shock Upper Bolt	10 Nm	-
Idler Pivot	20 Nm	⚠️ No axle rotation
CS Yoke / SS Link	14 Nm	⚠️ No axle rotation
Mid Link	14 Nm	⚠️ No axle rotation
Rocker Link	14 Nm	⚠️ No axle rotation

⚠️ Critical: The "no axle rotation" notes are critical footgun warnings. Over-torquing can damage suspension linkage geometry. Ensure bolts are tight but do not force them beyond the specified torque value.

Overview

The Nighttrain 170mm supports a dual-idler chain setup for enhanced drivetrain performance and reduced chain slap. Follow these steps for proper installation.

Chain Length Specification

• Total Chain Links: 38 links (including quick link)
• This is the correct length for proper idler tension and drivetrain engagement

Bottom Bracket Spacing

Setup Procedure

1. Remove existing chain and measure current setup
2. Install chain with 38-link specification
3. Position idler pulleys for optimal chain tension
4. Ensure idler pivots move freely without binding
5. Verify chain alignment with all gears
6. Test smooth shifting across all gear combinations
7. Torque idler pivot bolts to 20 Nm (no axle rotation)
8. Perform break-in ride and re-check tension
9. Inspect for chain slap and adjust idler position if needed
10. Perform final torque verification of all linkage bolts
11. Check for proper cable routing and frame clearance
12. Complete system test with full suspension articulation

Maintenance Notes

• Check idler pivot torque monthly during break-in period
• Inspect chain wear regularly, especially with dual-idler setup
• Clean idler pulleys during regular maintenance
• Re-tension if chain noise develops