{"product_id":"ohlins-piston-77-4-55-1-21862-01","title":"Öhlins Piston 77.4\/55.1 – 21862-01","description":"\u003cp\u003ePiston 77.4\/55.1, Öhlins part number 21862-01. Öhlins machines its pistons rather than sintering them, which is why the port edges stay sharp.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eOriginal Öhlins service part\u003c\/li\u003e\n\u003cli\u003eDimension A 77.4 mm\u003c\/li\u003e\n\u003cli\u003eDimension B 55.1 mm\u003c\/li\u003e\n\u003cli\u003eÖhlins part number 21862-01\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFunction\u003c\/h2\u003e\u003cp\u003eDimensionally this is 77.4 mm, 55.1 mm, which is how it is told apart from the rest of the range. Öhlins machines the ports rather than casting them, so the edges stay sharp and the flow predictable. Port area sets how much oil can pass before the shims begin to lift. A worn piston band lets oil past the outside of the piston, which shows up as damping that has gone soft.\u003c\/p\u003e\u003ch2\u003eWhy the Original\u003c\/h2\u003e\u003cp\u003eÖhlins manufactures service parts on the same lines as production parts — there is no second quality. The part is identical to what Öhlins fits in production — same supplier, same specification. Service parts are ordered per piece unless stated otherwise. If you are between two sizes, send us the measurement and we will check it against the catalogue.\u003c\/p\u003e\u003ch2\u003eGetting the Number Right\u003c\/h2\u003e\u003cp\u003eÖhlins identifies this position by the number 21862-01 in the exploded view for the unit it belongs to. Check dimension a 77.4 mm, dimension b 55.1 mm against what you have removed; a close size is not the same part. Twin-tube pistons have separate paths for compression and rebound, which is the whole point of the design. The piston carries the shim stacks and meters the oil; its port layout is what makes an Öhlins damper behave the way it does.\u003c\/p\u003e\u003ch2\u003eFitting and Setup Service\u003c\/h2\u003e\u003cp\u003eAsk us about a full service: as an authorised Öhlins centre we strip, inspect, replace what is worn and set the unit back to its specification.\u003c\/p\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cem\u003eBrand:\u003c\/em\u003e Öhlins\u003c\/li\u003e\n\u003cli\u003e\n\u003cem\u003ePart Number:\u003c\/em\u003e 21862-01\u003c\/li\u003e\n\u003cli\u003e\n\u003cem\u003eCategory:\u003c\/em\u003e Pistons\u003c\/li\u003e\n\u003cli\u003e\n\u003cem\u003eDimension A:\u003c\/em\u003e 77.4 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cem\u003eDimension B:\u003c\/em\u003e 55.1 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cem\u003eCountry of Origin:\u003c\/em\u003e Sweden\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Öhlins","offers":[{"title":"Default Title","offer_id":53652890517770,"sku":"21862-01","price":116.33,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7831\/0410\/files\/21862-01_67a91a72-2caf-439c-b4dc-13536adb49b9.png?v=1788880353","url":"https:\/\/inter-pace.com\/products\/ohlins-piston-77-4-55-1-21862-01","provider":"Inter-Pace","version":"1.0","type":"link"}