bearing calculations

[cassian]

l am designing a trolley which is suppossed to carry 5 tones of material, can you help me with the formulars to calculate the bearing sizes

 

[unclesyd]

You need to provide a little more information as to the type bearings, playing ball or roller . Is this a trolley tramway, monorail, etc.
Is it possible to use a Monorail?

If you are in the US this will come under OSHA as a underhung device that requires some specific design requirements.

 

[geesamand]

You will find a good treatment of the basics here:

http://catalog.timken.com/WebProject.asp?CodeId=7.4.4.3&BookCode=tmk09flx#

(It's the Timken bearing catalog, engineering section)