i slapped on the oem coupe 17"s for winter last week and i've been having a problem with a few of the lugs on ONE wheel only keep coming loose. i hope some of you can figure out why since sears who put them on for me (had to do alignment also) did not have the slightest clue.

1. can someone show me what lugs they are using for the oem 17"s? i went from the oem 19"s, did not use the 19" lugs.

2. are the 07+ G35 sedan studs/thread pattern the same as an 07 g35 coupe? the person who sold it to me put the 17"s on his car and gave me the lugs that he used and said it should fit my coupe.

3. can the reason be that sears torqued the lugs to high, and being that the lugs might be different for my studs, cross-threaded my studs?

4. i lost one of my oem wheel locks from this problem. i was wondering can the dealer replace that one lock, or would i have to buy a whole new set?

here's a pic of the lugs i used. the smaller lugs were used on my 19"s, the bigger lugs are currently being used for the 17"s:

 

any ideas? i can't drive anywhere far without stopping and retightening the lugs. ahhhhhhh