KONI 8241-1305SPORT Sport Rear Shock Yellow 16-25 Mazda MX-5 ND Fiat 124 Spider

Vehicle Fitment

• 2016-2025 Mazda MX-5 Miata Sport Soft Top (ND; SkyActiv-G 2.0L, RWD)
• 2016-2025 Mazda MX-5 Miata Club Soft Top (ND; SkyActiv-G 2.0L, RWD)
• 2016-2025 Mazda MX-5 Miata Grand Touring Soft Top (ND; SkyActiv-G 2.0L, RWD)
• 2017-2025 Mazda MX-5 Miata RF Club (ND RF; SkyActiv-G 2.0L, RWD)
• 2017-2025 Mazda MX-5 Miata RF Grand Touring (ND RF; SkyActiv-G 2.0L, RWD)
• 2020 Mazda MX-5 Miata 100th Anniversary Special Edition - Soft Top & RF (ND; SkyActiv-G 2.0L, RWD)
• 2017-2020 Fiat 124 Spider Classica (ND platform; 1.4L MultiAir Turbo, RWD)
• 2017-2020 Fiat 124 Spider Lusso (ND platform; 1.4L MultiAir Turbo, RWD)
• 2017-2020 Fiat 124 Spider Abarth (ND platform; 1.4L MultiAir Turbo, RWD)
• 2019-2020 Fiat 124 Spider Urbana Edition (ND platform; 1.4L MultiAir Turbo, RWD)

Fitment Notes

• Rear shock absorber - position is Rear Left and Rear Right. Left and right units are identical (non-handed). Sold individually (per shock); two units are required for a complete rear axle installation.
• Fits both the Soft Top and RF (Retractable Fastback) variants of the ND MX-5. The RF adds rear body weight compared to the Soft Top, so the correct spring perch position differs between variants - see Spring Perch Positions in Fitment Notes below.
• The Fiat 124 Spider was built by Mazda in Japan on the same ND MX-5 platform with the same rear suspension geometry, making this KONI rear shock a confirmed fitment for all 124 Spider trims including the turbocharged Abarth.
• Spring Perch Positions - Mazda MX-5 Miata:
  • Perch 1 (highest / top circlip position): Factory ride height on OEM springs. Recommended for RF variants paired with aftermarket springs targeting moderate lowering.
  • Perch 2 (middle): Approximately 20 mm lower on Club/Grand Touring springs; approximately 30 mm lower on Sport (base) model springs. Recommended for Soft Top models paired with aftermarket springs.
  • Perch 3 (lowest): Approximately 30 mm lower on Club/Grand Touring springs. Not recommended for Sport (base) model springs.
• Spring Perch Positions - Fiat 124 Spider (all trims including Abarth):
  • Perch 1 (highest): OE factory ride height
  • Perch 2 (middle): Approximately 20 mm lower on factory springs
  • Perch 3 (lowest): Approximately 30 mm lower on factory springs
• Installation note: The shock rod is 12 mm diameter. The factory bump-stop washer has a 10 mm bore - the washer must be drilled out slightly (approximately 2 mm) to clear the shock rod during installation.
• Rebound adjustment direction: CLOCKWISE = Softer; COUNTER-CLOCKWISE = Stiffer. Ships set to full-soft position. Do not use at the extreme full-soft or full-firm limits - set to at least one click off either end before driving.
• Companion front shock: KONI 8241-1304SPORT. Sold per shock - two rear units required for a complete rear axle installation.

Features

• KONI Sport 8241 Series externally adjustable rebound damping - the adjustment knob at the top of the damper allows rebound to be tuned from full soft to full firm without removing the shock from the vehicle, enabling on-car adjustment for street, autocross, and track configurations.
• Circlip height-adjustable spring perch - three selectable positions allow the rear ride height to be set at factory height, approximately 15-20 mm lower, or approximately 30 mm lower using the factory springs, without requiring separate lowering springs for a basic drop. Compatible with aftermarket performance springs for a wider range of setups.
• Covers both Soft Top and RF variants of the ND MX-5 - the multiple perch positions compensate for the different spring loads between the lighter Soft Top and the heavier RF body, making a single part number suitable for the entire ND lineup.
• Twin-tube, low-pressure gas-charged construction engineered for the ND MX-5's rear multi-link suspension geometry, delivering improved body roll resistance, rear axle composure, and more precise handling feedback over OEM or worn replacement shocks.
• Yellow-painted shock body - KONI Sport's iconic finish, and the established benchmark rear shock upgrade for the ND MX-5 and Fiat 124 Spider within the Miata autocross and track community.
• Approximately 100% rebound adjustment range - up to three times the range of competing adjustable shocks - accommodating OEM spring rates through high-rate aftermarket performance springs without requiring a different unit.
• Effective for daily street driving on OEM springs with stock ride height, as well as competition setups with lowering springs and custom chassis rake (one end lower than the other), or coilover-style fixed-perch configurations.
• Re-buildable and re-valvable - extends service life and enables custom valving for dedicated competition builds.
• Backed by KONI North America's Limited Lifetime Warranty for street use in the United States and Canada.

Specifications

• Part Number: 8241-1305SPORT (also referenced as 8241 1305SPORT / 82411305SPORT)
• Product Line: KONI Sport 8241 Series
• Position: Rear (Left and Right - non-handed, both sides use same unit)
• Companion Front Part: KONI 8241-1304SPORT
• Damper Color: Yellow
• Internal Design: Twin-Tube, Low-Pressure Gas-Charged
• Valving Adjustability: Yes - External Rebound Adjustment Knob (adjustable on-vehicle; CW = softer, CCW = stiffer)
• Adjustment Range: ~100% (full soft to full firm)
• Spring Perch: Circlip height-adjustable - 3 positions (factory height / ~15-20 mm drop / ~30 mm drop on OEM springs)
• Shock Rod Diameter: 12 mm (factory bump-stop washer requires drilling from 10 mm to 12 mm for installation)
• Re-buildable / Re-valvable: Yes
• Quantity: Sold individually (per shock)
• Application: 2016-2025 Mazda MX-5 Miata (ND, all trims, Soft Top & RF); 2017-2020 Fiat 124 Spider (all trims incl. Abarth)

Included Components

• 1x KONI Sport 8241-1305SPORT Rear Shock Absorber (Yellow)

Product Description

The KONI 8241-1305SPORT is a yellow-painted, externally adjustable rear shock absorber from KONI's Sport 8241 Series, purpose-built for the fourth-generation Mazda MX-5 Miata (ND platform, 2016-2025) and all trim levels of the 2017-2020 Fiat 124 Spider - including the turbocharged Abarth. Both vehicles share the same ND rear multi-link suspension architecture, as the Fiat 124 Spider was manufactured by Mazda in Japan on the same platform. A single part number covers the entire rear of the ND lineup, including both the Soft Top and the heavier RF (Retractable Fastback), with the multiple spring perch positions providing the necessary ride height compensation between variants. Left and right rear units are identical - two are required for a complete rear axle installation. The companion front shock is KONI 8241-1304SPORT.

The 8241-1305SPORT introduces two key adjustability features that set it apart from a standard replacement shock. The external rebound knob allows the damping to be tuned from full soft to full firm on-car without tools, with approximately 100% of range - from a comfortable daily street setting to a firm autocross or track tune. Turning clockwise softens the damping; counter-clockwise firms it up. The shock ships set to the full-soft position and should be moved off the extreme settings before driving. The circlip height-adjustable spring perch adds a second dimension of tunability: three selectable positions allow the rear ride height to be set at factory height, approximately 15-20 mm lower, or approximately 30 mm lower on factory springs, without requiring a separate lowering spring for a basic drop. This also enables chassis rake adjustment (one end lower than the other) and compatibility with coilover-style fixed-perch spring setups.

Installation requires drilling the factory bump-stop washer from its stock 10 mm bore to 12 mm to clear the shock's 12 mm rod - a minor one-time modification. The perch position for the RF variant should be set one position higher than for a Soft Top with the same spring to account for the RF's additional rear body weight. For the Fiat 124 Spider, all three trims use the same perch positions: factory height at Perch 1, approximately 20 mm lower at Perch 2, and approximately 30 mm lower at Perch 3. The damper is re-buildable and re-valvable, extending its service life for high-mileage street cars and enabling custom valving for dedicated competition builds. Backed by KONI North America's Limited Lifetime Warranty for street use in the United States and Canada.