There was a reality show about NYC messengers awhile back. In one of the two eps that aired,one of the guys had his wheels stolen. He just had the frame locked,the wheels were nutted,and they were taken from out in front of the place where he worked. Considering how many 'fixie tools' out there have a 15mm,I wouldn't consider them to be real security.
Pinhead/Pitlock for quick lockups,otherwise two locks or lock/cable.
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