Aux belt squeal on cold start

[Cro]

Changed to cup alternator setup recently and put a new aux belt on.

Its just started squealing after a few thousand miles but only for 3 minutes or so while the car warms up and then its gone, even on startup again.

The belt was tightened enough so that it can be twisted 45degrees on pretty much every straight bit.

Any ideas? Loosen, tighten, lube it up ?

 

[-Woody-]

tighten, my knowledge is limited but ive tightened it on 2 previous cars and not had a problem

 

[Reyes]

As above^