Built to order, to your spec. The TL-ONE is Thunder Lane US’s track-focused single adjustable coilover system for the BMW F8X M3/M4. Every set is hand-assembled and bespoke-valved to match your tire, aero, grip level, and goals — whether that’s HPDE, autocross, time attack, or wheel-to-wheel.

Included with every order: CVP + PVP dyno graphs, build-to-order spring rate selection, and damping tuned for repeatable performance.

What this kit delivers

• Confidence and consistency on entry, mid-corner, and power-down
• Real low-speed control for tire management and predictable balance
• Usable travel at your target ride height (not riding bump stops)

TL-ONE hardware highlights

• 46mm monotube dampers with advanced piston technology and check valves
• 20-click rebound adjustment for fast, meaningful track-side tuning
• Independent ride height and preload adjustment
• Electroplated bodies for long-term corrosion resistance
• Spherical bearing top mounts for precise response and alignment stability
• 2.5" linear springs with customizable spring rates (Swift optional)
• Rebuildable & serviceable — individual replacement parts available

Spec options (we confirm with you)

• Fitment: BMW M3 (F80) / M4 (F82/F83)
• Spring rates: track-ready defaults or your requested rates
• Valving profile: linear or digressive (based on your use case)
• Top mounts: spherical mounts / camber plates when applicable

FAQ