K-Tech KTR-4 Fork with Direct Damping System – Part No. 155-017-770

Built exclusively for the demands of professional circuit racing, the K-Tech KTR-4 fork with Direct Damping System represents the current state of the art in competition suspension engineering. Proven at the highest level — including the British Superbike Championship and the Isle of Man TT — this 770 mm fork delivers the precision, stability and repeatable damping control that separates podium finishers from the rest of the field.

Key Features

• Direct Damping System (DDS) eliminates cavitation and ensures consistent, predictable damping response under sustained racing loads.
• Outer tubes machined from 7075-T6 aluminium for an exceptional strength-to-weight ratio, matched by a 7075-T6 aluminium axle carrier for maximum structural rigidity.
• DLC-coated inner tubes with Superfinish treatment drastically reduce stiction, improving small-bump sensitivity and extending service life.
• Independent compression and rebound circuits each offer 30 clicks of adjustment, allowing fine, repeatable tuning for any circuit or riding style.
• 18 mm of adjustable spring preload accommodates a wide range of rider weights and track configurations.
• Compatible with 290–320 mm brake discs when used with 108 mm centre-mount calipers — genuine flexibility for different circuit set-ups.

Direct Damping System — Why It Matters

Conventional cartridge forks rely on oil passing through stacked shims inside a sealed cartridge, a design that is inherently susceptible to cavitation under rapid, repeated inputs. K-Tech's Direct Damping System routes the oil flow path more directly through the damping circuit, eliminating the air entrainment that causes cavitation and the associated fade in damping force. The result is a fork that behaves identically on lap one and lap thirty, giving the rider and engineer a reliable, repeatable baseline to work from. Independent compression and rebound circuits mean changes to one characteristic have no cross-talk effect on the other — a critical advantage when chasing fine set-up adjustments between sessions.

Materials and Construction

The KTR-4 outer tubes and axle carrier are both produced from 7075-T6 aluminium, one of the strongest aluminium alloys available and the same grade used throughout aerospace and high-performance motorsport applications. The sliding inner tubes receive a Diamond-Like Carbon (DLC) coating followed by a Superfinish process, producing a surface hardness and smoothness that conventional hard-chrome or nitride treatments cannot match. Friction is minimised across the full range of fork travel, so the suspension reacts to even the smallest road or track surface irregularities — essential for maintaining consistent tyre contact and braking stability into fast corners.

Track Use and Installation

The KTR-4 is designed and approved for closed-circuit competition use only. Installation requires specialist ancillary components including aftermarket triple clamps, handlebars and axle inserts. To ensure maximum safety and performance, fitting must be carried out exclusively by an authorised K-Tech Service Centre. This is not a bolt-on upgrade — it is a professional racing component that demands professional installation. Three pairs of K-Tech 36-260-series springs are included to allow immediate spring-rate selection and fine-tuning once the fork is fitted.

Fitment and Compatibility

The KTR-4 fork with part number 155-017-770 (770 mm overall length) is a universal competition fork designed to be adapted to a wide range of race machinery via appropriate triple clamps and axle inserts. It has been used on machinery competing across classes covering Aprilia, BMW, Ducati, Honda, Kawasaki, MV Agusta, Suzuki, Triumph and Yamaha platforms, including but not limited to: RSV4, S1000RR, 1199, 1299, CBR 1000 RR, GSX-R 1000, ZX-10 R, R1 and Daytona 675. Confirm exact clamp and insert compatibility with an authorised K-Tech dealer prior to ordering.

Specifications