The Ohlins HD645 is a rear STX 36 twin shock kit developed for Harley-Davidson Sportster XL models. Built around Ohlins damping know-how, it’s intended to improve chassis composure, grip and control without changing the character of the bike. As a twin-shock rear setup, it suits riders who want consistent, tunable suspension behaviour for road use.

Ohlins | Made to race, perfected to ride

Ohlins STX twin shocks focus on stable damping and predictable response over a wide range of conditions. The HD645 is designed as a direct rear twin-shock solution for Sportster XL fitment, aimed at riders wanting clearer feedback and better control from the back of the bike.

Shock design & features

This model uses an emulsion-style damping layout. The STX 36 architecture is designed to deliver consistent damping feel and improved rear-end control, helping the bike stay settled through braking zones, direction changes and uneven surfaces.

Tuning controls

The HD645 provides rebound damping adjustment and compression damping adjustment, allowing you to tailor how the shock reacts both when the rear extends and when it is being driven into the stroke. This makes it easier to balance comfort, support and traction for your load, tyres and riding conditions.

Who this shock is for

Suited to Sportster XL riders chasing firmer chassis control and more predictable rear grip compared with basic OE suspension. It’s also a good match if you ride briskly on back roads and want adjustment range to dial the bike in for your weight, road surfaces and typical pace.

Before you install

Confirm fitment for your exact Sportster XL year and model variant, and inspect linkage and mounting hardware condition before installation. After fitting, set rider sag and then fine-tune compression and rebound in small steps to reach a balanced feel front-to-rear.

Öhlins Motorcycle Suspension Warranty

New Öhlins motorcycle shock absorbers, front forks and cartridge kits supplied by Teknik Motorsport are covered by the applicable Öhlins manufacturer’s warranty against defects in materials and workmanship.

Teknik Motorsport is an authorised Öhlins Service Centre and administers warranty claims in accordance with the Öhlins warranty conditions. The service intervals below form part of the maintenance requirements for Öhlins products supplied and supported by Teknik Motorsport.

This warranty is in addition to the consumer guarantees that apply under the Australian Consumer Law.

  • Registered motorcycles — non-competition road use Five years, subject to correct application, installation, setup and servicing every: 20,000 km or two years, whichever occurs first.
  • Registered motorcycles — adventure and light off-road use Five years, subject to correct application, spring rate, setup and servicing every: 10,000 km or annually, whichever occurs first.
  • Unregistered or competition motorcycles Two years for eligible Öhlins MX and Enduro products, subject to inspection every ten hours and servicing every: 30 operating hours or annually, whichever occurs first.

Compliance with the applicable service interval is a condition of the Öhlins manufacturer’s warranty. Evidence of servicing may be required when a warranty claim is assessed.

A seal leak, loss of damping performance or internal wear arising after the prescribed service interval has been exceeded will be treated as a service or maintenance issue rather than a manufacturing defect.

Warranty repairs

Öhlins suspension products are designed to be serviced and repaired. Where a warranty claim is approved, the normal remedy is repair of the customer’s original suspension unit using genuine Öhlins replacement parts.

Replacement of a complete shock absorber, fork or cartridge kit is not automatic and would normally occur only where the product has suffered a manufacturing failure that cannot reasonably be repaired. This is at Ohlins discretion. 

Öhlins spare parts and service kits

Öhlins spare parts, seals, bushes, service kits, springs, fluids and individual components are covered only against defects present when supplied.

No fixed age-based warranty applies to wear items, service parts or consumable components. Wear, deterioration, contamination, incorrect installation and damage caused by another component are not manufacturing defects.

Öhlins gives the customer a meaningful five-year warranty on products (Units), provided the suspension is maintained as suspension should be maintained. Teknik supports that warranty locally, can inspect the product properly, and can repair it with genuine parts rather than discarding it.

SKU HD645
Model # S36E
Barcode # HD645
Brand Ohlins
Shipping Weight 5.0000kg
Shipping Size 0.300 x 0.300 x 0.500m
Type Units
See our Shipping Information See our Frequently Asked Questions
Position (Front or Rear) Rear Twin
Shock Length Eye to Eye (mm) 296.0
Spring Rate Standard 16.0 - 26.0 N/mm Progressive
Type Code S36E
Stroke Metal to Metal (mm) 71.0
Product Family STX 36 Twin
Fitted Spring 00380-04
Spring Colour Yellow

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