A high level of false twist in wrap spinning significantly affected yarn appearance and mechanical properties. Yarn spun under these conditions had a tortuous sturcture, whereas yar spun without a false twist crimping mechanism was smooth. False twist and zero false twist wrap yarns had a comparable twist strength relationship; however, the false twist wrap yarns had lower moduli and bending rigidities. Twist contraction of the yarn core during intial wrapping was primarily responsible for the tortuous structure. With the use of a false tiwst crimping mechanism, the yarn core initially contracted. At the same time as the contraction, the yarn was wrapped with a low wrap twist because of the difference in rotational speed between the wrapper balloon and the yarn core. Then, as the false twist was removed from the core and further wrap twist formed at the exit of the false twist crimping mechanism, the core recovered from twist contraction and buckled to form a helix. 15 refs.