I rarely use just loops now.. buts here's a quick tip to get your bpm...
now just follow what I do...
sample a ONE bar loop.
goto Trim and trim it so it loops perfectly
Now once that is done... while STILL in the trim window press LOOP(F2) at the bottom of the screen
now once there, hit the EDIT key (F5)
Window will say LOOP FROM START TO END
Press DO IT (F5)
once you pressed DO IT it'll take you back to the TRIM PAGE in LOOP Mode (see how LOOP is highlighted)
Bring your cursor up to where it says LOOP:OFF
Change it to LOOP:ON
Hold your pad down itll show if your ONE BAR loop is correctly trimmed.. but that's not the reason I made you do that...
Now hit the PARAMS button (F4)
Now in the PARAMS window select how many beats your ONE BAR loop is (of course.. 4 beats)
It will display the TEMPO of that loop
Now if your loop is looped up real tight the BPM should be close to exact...
NOW you know how fast your sample is going at... you shouldnt have any problems getting those drums to sync...
ADJUST TUNE: if you want it slower, faster, and/or to match with your current sequences TEMPO
Now this may have seemed liek a lot but once you get it down its a 20 second process, even quicker...