If your exercise bike or elliptical cross trainer makes a squeaking or creaking noise, check the following:
Elliptical cross trainer
Check that the inner sleeve is properly attached. It is either sometimes not fitted when installed or this sleeve may creep up into the steerer tube. This brings the frame and tube against each other, causing the squeaking or creaking noises.
Elliptical cross trainer/hometrainer
Check that all bolts are properly tightened. This concerns the bolts of the front and rear legs and of the steerer tube.
Check that the pedals are tightened.