Arrow Slip-On Thunder Aluminium Dark – KTM RC 390 (2017-2020) 71860AKN

Engineered with track performance in mind, the Arrow Thunder slip-on silencer in Aluminium Dark delivers a meaningful weight saving and sharper throttle response on the KTM RC 390 — exactly what riders demand when every tenth counts. At just 2.03 kg, the anodised dark aluminium canister replaces the heavy stock unit and lets the RC 390's single-cylinder engine breathe and rev with greater urgency, whether you are chasing lap times or carving road passes.

Key Features

• Weighs only 2.03 kg — reduces unsprung and overall mass for noticeably faster throttle response and more agile handling
• Aluminium Dark canister with carbon end cap — race-derived materials combine durability with aggressive, purposeful aesthetics
• Stainless steel internals — resist heat cycling and corrosion for consistent, long-lasting performance season after season
• E-number road approval — fully street-legal with the removable dB killer included for noise compliance without compromising character
• dB killer included — maintain legal sound levels on the road; remove it at the track for the full Arrow soundtrack
• Expandable to a full system — pair with an Arrow header for a complete performance exhaust installation

Build Quality & Performance

The Thunder canister's Aluminium Dark finish is not merely cosmetic — the treated aluminium alloy shell keeps weight to an absolute minimum while handling the sustained heat loads of hard track sessions. Internal components are fabricated from stainless steel, ensuring the silencer maintains its flow characteristics and structural integrity long after lesser units have degraded. The carbon end cap adds a final race-shop detail that looks at home on the circuit paddock or under scrutineering lights.

The 270 mm canister length has been optimised for the RC 390's exhaust pulse characteristics, promoting mid-range torque and top-end pull without requiring any ECU remapping for a noticeable on-road improvement. The 54 mm inlet and 50 mm outlet diameters are sized to maintain exhaust velocity at the engine speeds this bike uses most.

Installation Note

Fitting the 71860AKN requires the Arrow connecting pipe 71667MI, sold separately. Once the connecting pipe is in place, installation is straightforward and uses the standard mounting points. To build a complete Arrow exhaust system, the slip-on can be combined with an Arrow header/collector pipe for the RC 390.

Please note: the product image shown may have been digitally composed as a fitment reference, since Arrow had not yet released an official photography shot for this specific application at the time of listing. The silencer itself fully corresponds to the specifications described here and is confirmed for the KTM RC 390 2017-2020.

Fitment & Compatibility

• KTM RC 390 — model years 2017, 2018, 2019, 2020
• Requires connecting pipe Arrow 71667MI (sold separately)
• Compatible with Arrow header pipes for full-system conversion

Specifications