well carhartts really aren't meant to be tightened, but it mainly depends on the stitch around the crotch and how muthafuckin' tight they are. just like any other pant, they'll keep on ripping open if it's huggin your cock too much. i usually just do large u-shaped stitch in the crotch and make sure it doesnt hug my thighs too much, works for me. or just get durable stretchy material ( old mans pant works good) to patch up with and the crotch wont blow out....thats all i got