{"id":196,"date":"2026-11-11T08:43:06","date_gmt":"2026-11-11T08:43:06","guid":{"rendered":"https:\/\/www.astroline.co.com\/?p=196"},"modified":"2026-11-11T08:43:06","modified_gmt":"2026-11-11T08:43:06","slug":"main-bearings-vs-connecting-rod-bearings","status":"publish","type":"post","link":"https:\/\/www.astroline.co.com\/index.php\/2026\/11\/11\/main-bearings-vs-connecting-rod-bearings\/","title":{"rendered":"Main Bearings vs Connecting Rod Bearings: Which Set Do You Need?"},"content":{"rendered":"
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English<\/a> \/ Deutsch<\/a><\/p>\n

Main bearings support the crankshaft in the engine block. Connecting rod bearings support the big ends of the rods on the crankpins.<\/strong> They fit different positions. To order the right set, confirm where it goes and the size of the journal it must fit.<\/p>\n

Which part did the workshop mean?<\/h2>\n

\u201cCrankshaft bearings\u201d can be an imprecise description on an estimate. Ask whether the job calls for main bearings, rod bearings, or both. The catalogue may also list thrust washers separately, or use a flanged main bearing to control end play. Ask which arrangement applies and what the package actually includes.<\/p>\n

How to read STD and undersize<\/h2>\n

STD is the catalogue designation for the standard size. An undersize designation generally refers to a smaller journal diameter after approved crankshaft machining; it does not mean the bearing shell is thinner. Confirm the manufacturer\u2019s convention. Some engines also specify selective thickness grades, so \u201cstandard crankshaft\u201d alone may not identify the correct shell.<\/p>\n

Ask for the current measured diameters and size designations of the relevant main journals or crankpins. If machining is planned, ask when the shop can confirm the final dimensions. The main and rod sets need to be checked independently. The workshop must verify the assembled oil clearance to the engine specification.<\/p>\n

What to gather before ordering<\/h2>\n