Just How Big Are the Biggest Bearings?

I don’t recall a single bearing class where someone didn’t want to know what the largest bearing ever made was. From my stint as a bearing engineer in heavy industry, I gained quite an appreciation these behemoth bearings and the machines that use them. On the engineering side, there really isn’t all that much difference. There are a couple of extra zero’s, but the principles and techniques are fairly transferrable between a 1 inch bearing and a 1 yard bearing.

Chasing down THE largest bearing is tricky…because everyone wants the credit and most of the largest bearings are custom built with only 1 or 2 being built with a couple of replacements. Certainly, we can narrow the field down to some select.

Machinery: Wind turbines, drag lines, continuous miners, mining trucks, tunnel bores and perhaps a little surprisingly, giant Ferris wheels.
We covered a story back in 2007 that is very well in contention from SKF for the Repower Systems 5M Wind Turbine. The 5M’s bearing, with its 1.5-meter inside diameter, weighs 2,700 kg and is the largest of its type ever manufactured by SKF. https://www.powertransmission.com/issues/0207/skf.pdf

Slewing ring bearings are quite an animal that can grow up to 25’ in diameter or more. These are usually assembled on site with the rings shipped upright on a semi. These giant slewing (or turntable) are used under large bases that have to turn; think draglines, steel mill cranes, construction cranes, etc. You can see a 24’ bearing being assembled here: https://www.youtube.com/watch?v=2cA9CuKHg6k. These bearings can easily pass $300k each and insurance companies will usually require that at least one replacement bearing is produced and stored.

There are so many great applications; mining truck wheel end tapered rolling bearings, steel mill multi-row rollneck bearings, crane sheave bearings, the applications are numerous.
What is the largest bearing that you know of? I would interested in finding THE largest bearing ever made.


About Author

Norm Parker

Norm Parker is currently the global senior specialist - roller bearings at FCA US LLC. With his bachelor and master degrees in mechanical engineering from Oakland University (Rochester, Michigan), Parker has developed a keen interest in the academic, commercial and engineering aspects of the bearing industry. Prior to joining FCA, he rose through the ranks of traditional bearing companies and served as bearing technical specialist for the driveline division at General Motors. He is a regular contributor to Power Transmission Engineering Magazine, appearing often in the publication’s popular Ask the Expert feature, as well as authoring a number of bearings-oriented feature articles and The Bearing Blog. The views expressed in this blog are Parker's personal views and they do not represent the views or opinions of FCA in any way.


  1. Carl
    Carl 29 September, 2015, 02:31

    I worked for a bearing distributor in Boston many years ago and when I was working there I saw a photograph of a bearing that was used for mobile caddies that carried, I believe, Saturn rockets and stood them up from horizontal position. It was lying on a floor with a woman standing inside of it and I don’t remember ever seeing a bearing that was larger in diameter. Wish I could find a photo of it again.

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  2. Kristin
    Kristin 15 February, 2018, 14:38

    There is a 17.5-foot diameter ball bearing inside the 140-foot radio telescope at Green Bank Observatory, in Green Bank, West Virginia. When I visited there (almost 20 years ago) they claimed it was the largest ball bearing in the world.

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