The Ohlins KA639 is a TTX RT rear shock absorber developed for the Kawasaki ZX-6R platform, aimed at riders who want consistent damping control and clear chassis feedback. Built around Ohlins’ twin-tube damping concept, it is designed to manage heat and maintain stable behaviour over longer sessions. This unit is suited to both track-focused riding and fast road use where suspension consistency matters.

Ohlins | Made to race, perfected to ride

TTX RT shocks use a twin-tube architecture to keep damping forces more consistent as conditions change. The design prioritises predictable support through corner entry, mid-corner and exit, with a strong emphasis on usable adjustment rather than complexity for its own sake.

Who this shock is for

This rear shock suits ZX-6R riders chasing improved stability under braking, better drive on corner exit, and a more controlled feel when the pace increases. It’s also appropriate for riders who regularly change tyres, ride heights or track conditions and need a broader tuning window than a standard shock typically provides.

Shock design & features

This is an oil/gas separated shock (not an emulsion design), helping maintain damping consistency during hard use. The TTX RT layout separates and balances damping flow paths to improve response to sharp inputs while keeping overall control through longer, loaded corners.

Tuning controls

The KA639 provides external damping adjustments for both compression and rebound, allowing you to tune support and grip balance to suit tyres, pace and surface conditions. These controls are intended to make changes repeatable and meaningful, whether you’re addressing corner-entry stability, mid-corner support, or exit traction.

Before you install

• Confirm fitment for your exact ZX-6R model and year, and check clearance around linkages and any aftermarket exhaust components.
• Ensure your baseline sag and ride height are set correctly after installation before making damping changes.
• If your bike has already been lowered/raised or has altered linkage geometry, factor that in before assessing damping behaviour.

Serviceability/lifecycle

This Ohlins unit is designed to be serviced and re-valved as required. Routine maintenance helps keep damping behaviour consistent over time, particularly if the bike sees regular track use.