Are bigger bearings better?

[RainbowsParticipant @rainbows]

Say I wanted taper roller bearings to fit over a 30mm shaft.

If I go to Wych bearings looking through the Timken brand ones I can get a bearing with a 55mm OD and 17mm thickness or I can get a bearing with a 72mm OD and 28.75mm thickness. There are also sizes inbetween ofcourse.

I checked the bigger bearings because I thought that larger parts might be easier to manufacture thus have lower prices but the biggest is twice the cost of the smallest.

Anyone know how much better a larger bearing is in what ways? I'm assuming they can take stronger forces but I don't know where I would get a data sheet with the different maximum loads and such.

[RainbowsParticipant @rainbows]

[Chris Evans 6Participant @chrisevans6]

I think it is a case of what do you intend to do with them. The bigger ones may just "Over Engineer" the project. I use Simply Bearings on a regular basis with good service/web site.

[Keith LongParticipant @keithlong89920]

Rainbows – the load data and everything else is readily available, try sticking "Timken bearing catalogue" into Google and go from there. You can have the data as pdf, fully interactive on line etc.

[AjohnwParticipant @ajohnw51620]

The basic data is given on Wych when specification is clicked. Much like SimplyBearings.

Really it all depends on what the 30mm shaft is for but in general the larger the od the thick bearing and the larger the rollers and the bigger the load they can take usually with some effect on max speed.

John

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[Tim StevensParticipant @timstevens64731]

'Great engines move slow, but are not so soon put out of joint.'

I can't remember who (famously) said that a long time ago, but it applies to bearings, too. What it doesn't say is that lightness is the most important factor for many applications, and high speed for others.

So, it all depends what your 30mm shaft will be used for. If a handle on a well, anything will do, but inside a turbocharger for an aeroplane … well too big and too heavy will not do at all.

Cheers, Tim

[John McNamaraParticipant @johnmcnamara74883]

Hi Rainbows

Bearing design is part art part science.

This is a fairly easy to read get you started paper.

**LINK**

or this Google search

**LINK**

Regards
John

[John ReeseParticipant @johnreese12848]

Timken has load capacity vs life information available. Generally a larger bearing has increased load capacity.

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