Öhlins STX 36 Twin Shock Absorber Harley Davidson Dyna Fat Bob FXDF (2007–2017) – HD 817⟲ 360° — drag me
02 · Data & docs

The facts.

Technical data
BrandÖhlins
Part NumberHD 817
FitmentHarley Davidson Dyna Fat Bob FXDF (2007–2017)
Road ApprovalABE (Germany)
Length305 mm
Stroke61 mm
Spring Rate32 N/
Piston Diameter36 mm
Spring Part Number21180-01
Product LineSTX 36 Twin
DescriptionThe whole story▼

Öhlins developed HD 817 around the Harley Davidson Dyna Fat Bob FXDF (2007–2017) — its weight, its linkage and its geometry. The difference shows up in the second half of a fast road, when the standard unit has warmed through.

Key Features

  • Monotube damper layout
  • 61 mm of damper stroke
  • Adjustable rebound damping via the knob above the lower eyelet
  • Öhlins fits a 32 N/mm spring to this application
  • Gas-pressurised monotube damper with the reservoir integrated into the body
  • Spring part number 21180-01 fitted
  • Built to 305 mm installed length
  • Direct fitment on the Harley Davidson Dyna Fat Bob FXDF (2007–2017)

The Dyna Fat Bob FXDF in Particular

Öhlins covers the 11-year production run of this generation with a single part number, which means the mounting and the linkage stayed unchanged across it. Short travel and substantial mass are a hard combination: there is little room to absorb anything, so damping quality matters more.

Construction and Material Quality

Service parts stay available for years after a part number leaves the current price list. Machining, anodising, assembly and testing all happen in the same building rather than across a supply chain. Every unit is dyno-tested against the curve held for its part number, not sampled from a batch.

Damping Performance

Damper stroke comes to 61 mm on this number. Öhlins specifies 36 mm for the piston on this number. Öhlins supplies spring 21180-01 with this unit. Öhlins builds it to 305 mm between the eyes for this chassis. The two adjusters do genuinely separate jobs, which is what makes methodical setup possible. Adjustment is by click rather than by feel, so a setting can be written down and returned to.

About the STX 36 Twin Range

Twin-shock machines share the load between two units, and that changes everything about how each one is specified: half the load, but also half the leverage and often a steeper mounting angle. Twin-shock installations load each damper differently from a monoshock, and Öhlins specifies the pair accordingly. Öhlins offers several body and spring finishes in this range because the shocks are visible on the machines that use them.

Fitment and Compatibility

This listing covers Öhlins part number HD 817 for the Harley Davidson Dyna Fat Bob FXDF, 2007–2017. Nothing about it is generic — the mounting dimensions alone rule out a different model.

Road Approval

Road approval: ABE (Germany) for the Harley Davidson Dyna Fat Bob FXDF. That means no TÜV appointment and no entry in the registration document — the paperwork comes in the box.

Specifications

  • Brand: Öhlins
  • Part Number: HD 817
  • Fitment: Harley Davidson Dyna Fat Bob FXDF (2007–2017)
  • Road Approval: ABE (Germany)
  • Length: 305 mm
  • Stroke: 61 mm
  • Spring Rate: 32 N/mm
  • Piston Diameter: 36 mm
  • Spring Part Number: 21180-01
  • Product Line: STX 36 Twin
FitmentWhich bikes this fits▼
  • Harley Davidson Dyna Fat Bob FXDF (2007–2017)
07 · Support

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