Shock Oil
 

What can people tell me the differences in shock oil brands? I am running AE 30 oil in my touring car and people are telling me that to be the same as x-ray 30 I need to go to like a 50wt. This doesn't make any sense to me as oil wt should be pretty consistant throughtout the different brands I would think. Any help or if anyone can point me in a direction of a cross reference chart that would be great as well.