There are theories to support tighter and looser crosses.
Ramon highlighted the tighter cross theories above - crosses increase main tension so cross needs to be tighter to keep up with increase to main.
Others say crosses should be lower because 1. it is a shorter string and doesn't need as much tension to feel as stiff, and 2. dropping approximately 2 lbs on the cross allows the mains to slide more easily.
Finally, some say it doesn't matter and just use the same tension.
I will offer an opinion that pros seem to like the crosses a bit lower than the mains in general. From what I have observed this seems more common. This opinion is just based on pro stringing logs I have seen on TT and other web sites.
Then hybrid stringing with a poly and soft gut/syn gut/multi brings in a whole range of other questions. I like stringing the soft gut/syn gut/multi 2-5 lbs tighter than the poly. I do this if poly is in the mains or the crosses - I always increase the soft string 2-5 lbs - maybe +2-3 lbs if the soft string is in the crosses and +4-5 lbs if the soft string is in the mains.
For non-hybrid stringing, I like cross -2 lbs below mains. But, try it both ways and decide for yourself is the only real way to know.
Last edited by TennisCJC; 06-19-2013 at 05:24 AM.