The facts.
| Brand | K-Tech |
|---|---|
| Part number | FSS-021 |
| Seal manufacturer | NOK |
| Inner diameter | 43.00 mm |
| Outer diameter | 55.10 mm |
| Height (1) | 11.00 mm |
| Height (2) | 14.00 mm |
| Quantity | 2 oil seals (pair) |
| Fitment | Aprilia RSV4 / RSV4 1100 Factory / R / RR / RF (2009–2026) |
DescriptionThe whole story▼
Suspension integrity on the Aprilia RSV4 and RSV4 1100 begins with seals that can handle the demands of both road and track. The K-Tech FSS-021 oil seal kit is manufactured by NOK — the supplier of choice for leading Japanese suspension manufacturers worldwide — and brings that same engineering rigour directly to your fork service. When only factory-grade materials will do, this is the kit that delivers.
Key Features
- NOK-manufactured seals, chosen by premier Japanese suspension OEMs for their exceptional durability and consistent sealing performance
- Direct OEM-equivalent replacement — precise dimensional match ensures no compromise in damping characteristics or seal life
- Supplied as a complete pair so both fork legs are serviced simultaneously, maintaining balanced suspension action
- Precision dimensions of 43.00 x 55.10 x 11.00/14.00 mm guarantee a factory-correct fit in the RSV4 fork tubes
- Effective dual-lip construction keeps fork oil in and road contamination out, preserving smooth, consistent damping over the long term
- Covers all RSV4 and RSV4 1100 variants — Factory, R, RR and RF — across the full 2009–2026 production span
Build Quality and Materials
The defining characteristic of the FSS-021 kit is provenance. NOK is not a generic aftermarket supplier; they are the original-equipment seal manufacturer behind many of the world's most respected suspension units. Their production process demands tight dimensional tolerances and compound consistency that cheaper alternatives cannot match. The result is a seal that seats cleanly, resists premature wear and maintains its lip profile across temperature cycles — from cold pre-dawn warm-ups to sustained track sessions where fork temperatures climb significantly.
For the Aprilia RSV4 platform — a chassis known for precise, reactive front-end feel — this level of manufacturing quality is not a luxury. A weeping fork seal introduces unwanted variables into suspension behaviour and contaminates the brake disc if left unaddressed. Fitting seals of this calibre during a fork service eliminates those risks and restores the front end to the condition it left the factory in.
Installation Note
Installation of fork oil seals requires specialised tools and a working knowledge of suspension servicing procedures. K-Tech recommends that fitting is carried out by an authorised K-Tech Service Centre to ensure full performance and safety of the product.
Fitment and Compatibility
The K-Tech FSS-021 seal kit is designed as a direct replacement for the following Aprilia models:
- Aprilia RSV4 R — 2009 to 2015
- Aprilia RSV4 Factory — 2009 to 2015
- Aprilia RSV4 RR — 2015 to 2020
- Aprilia RSV4 RF — 2015 to 2020
- Aprilia RSV4 1100 — 2019 to 2026
- Aprilia RSV4 1100 Factory — 2019 to 2026
Specifications
- Inner diameter: 43.00 mm
- Outer diameter: 55.10 mm
- Height (1): 11.00 mm
- Height (2): 14.00 mm
- Quantity: 2 oil seals per kit
What's includedEverything in the box▼
- 2x K-Tech fork oil seals for Aprilia RSV4 / RSV4 1100 Factory / R / RR / RF (2009–2026)
FitmentWhich bikes this fits▼
- Aprilia RSV4 / RSV4 1100 Factory / R / RR / RF (2009–2026)
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