I have a set of aftermarket wheels just installed on my 2010 RX 350. Both the wheels and lug nuts are Acorn style (which match). Here's my question: I am only able to have the nuts 6.5 turns in the front and 5 turns in the back. Is this okay??

 

i hope i can make this make sense. i had the same issue on my old car with a set of wheels from another car. the basic rule of thumb that ive found is that you need to get at least enough thread engagement equal to the diameter of the bolt. for example if its a 1/2 bolt and the bolts has 13 thread per inch. the nut will have to thread in 1/2" or at least 6.5 thread or 6.5 turns. i don't know what the threads of the rx are. im guessing its metric, but your lug nuts should tell you too, ie m12 or something like that. so you should be able to figure it out.

 

if you are really concerned....Put them on with a torque wrench... Can we see some pics please