{"product_id":"cuscinetto-serie-sterzo-fsa-1-3-8-is-2-138-acb-36-x45-dual-seal-mr031-nero","title":"Fsa 1-3\/8'' IS-2-138 ACB 36°x45° dual seal MR031 headset Bearing - Black","description":"\u003cdiv class=\"data item content\" id=\"description\" role=\"tabpanel\"\u003e\n\u003cdiv class=\"product attribute description\"\u003e\n\u003cdiv class=\"value\"\u003e\n\u003ch3\u003eFSA 1-3\/8\" Headset Bearing IS-2-138 ACB: Performance and Reliability\u003c\/h3\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eFSA 1-3\/8\" headset bearing\u003c\/strong\u003e is a high-quality technical solution for modern bicycle steering systems. This \u003cstrong\u003esealed bearing\u003c\/strong\u003e is designed with 36° and 45° contact angles, ensuring optimal load distribution and directional stability while riding. The dual seal configuration effectively protects against dirt and moisture, maintaining mechanical performance over time. The \u003cstrong\u003eCr-Mo balls\u003c\/strong\u003e provide superior wear resistance and reliability in a wide range of riding conditions, from road rides to more demanding trails.\u003c\/p\u003e\n\n\u003ch3\u003eDimensional Specifications and Component Composition\u003c\/h3\u003e\n\n\u003cp\u003eThe inner and outer dimensions are calibrated to ensure compatibility with next-generation \u003cstrong\u003eIS-2-138 headset systems\u003c\/strong\u003e. With an inner diameter of 37mm and an outer diameter of 48.9mm, this \u003cstrong\u003eball bearing\u003c\/strong\u003e offers a compact height of 6.5mm, ideal for precise integration in the steerer tube. The \u003cstrong\u003e36°x45° angular geometry\u003c\/strong\u003e optimizes resistance to lateral and vertical forces. The 22 Cr-Mo alloy balls, each with a diameter of 1.8\", distribute forces evenly, reducing concentrated stress and extending the component’s service life.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Advantages and Applications\u003c\/h3\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eACB design\u003c\/strong\u003e (Angular Contact Ball) is the standard for high-performance headset bearings, preferred by professional builders and mechanics. The \u003cstrong\u003edual sealed protection\u003c\/strong\u003e keeps internal lubrication in place even in damp or dusty environments, reducing the need for frequent maintenance. This headset bearing is suitable for road bikes, gravel and mountain bikes with head tubes compatible with the IS-2-138 standard. The reliability of the \u003cstrong\u003eMR031 bearing\u003c\/strong\u003e makes it a trusted choice among cycling enthusiasts looking for durable, high-performance components, with smooth rotation and precise steering guaranteed over time.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Features\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eHeadset standard: \u003cstrong\u003eIS-2-138\u003c\/strong\u003e 1-3\/8\".\u003c\/li\u003e\n\u003cli\u003eInner diameter (ID): 37mm.\u003c\/li\u003e\n\u003cli\u003eOuter diameter (OD): 48.9mm.\u003c\/li\u003e\n\u003cli\u003eHeight (H): 6.5mm.\u003c\/li\u003e\n\u003cli\u003eContact angles: 36° (inner) and 45° (outer).\u003c\/li\u003e\n\u003cli\u003eNumber of balls: 22.\u003c\/li\u003e\n\u003cli\u003eBall diameter: 1.8\".\u003c\/li\u003e\n\u003cli\u003eBall material: \u003cstrong\u003eCr-Mo\u003c\/strong\u003e (chromium-molybdenum steel).\u003c\/li\u003e\n\u003cli\u003eProtection: sealed \u003cstrong\u003edual seal\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003eModel: MR031 FSA.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Fsa","offers":[{"title":"One size","offer_id":54681454215514,"sku":"160-6753","price":24.9,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0532\/7139\/6534\/files\/137494-406572292-mr031.webp?v=1788340689","url":"https:\/\/www.all4cycling.com\/en\/products\/cuscinetto-serie-sterzo-fsa-1-3-8-is-2-138-acb-36-x45-dual-seal-mr031-nero","provider":"All4cycling ","version":"1.0","type":"link"}