looping that shiit

alright, so i find a dope riff that would be a tight loop.. i sample it onto the mpc.. how should i go about looping it with a beat ? so that the timing is right..

right now im sampling, then editing so it can be looped, then i start it on the first note on a bar, then adjust the tempo so it lines up, and loops..
but then the bpm is too fast, or too slow for the beat ?

anyone got tips for this ?

write a beat to the loop, or slow down or speed up the looped sample, or timestretch somewhere else.

use the tap tempo.

Its a titty bit nipply outside...