Question: Can I use bulging lug nuts for the conventional steel wheels? I previously used the closed-end regular width lug nuts on steel wheels. (I used the same lug nuts on aluminum wheels.)
The story: I went to Costco to get a set of winter tires for my 2006 Ford Focus. I drove in with the summer tires on 16" aluminum alloy wheels, and I brought in a set of 15" steel wheels with old winter tires on them. The guys put new winter tires on the steel rims but would not put them on the car claiming that I had “wrong lug nuts.” What they mean was that the lug nuts for the aluminum wheels are different from those used on steel wheels. The holes on the steel wheels look like the conventional conical design, which appear to be the same as the aluminum wheels. (The contact surface on the aluminum wheels are greater, of course.) I had no problem with mounting the steel wheels over the last three winters with the same lug nuts. (I did the tire change over at home, so Costco didn’t have a say in the lug nuts until now.)
Since they refused, (these guys don’t listen that it was O.K. for three seasons.) I had to come home with the winter tires balanced and mounted on the steel rims in the trunk rather than on the car. I did the tire change over at home, but the new hub caps I bought don’t fit, because the closed-end type lug nuts extend too far out interfering with the hub caps. So, now I am looking for open-end type of lug nuts on eBay and found that there are the regular types and bulging types. The overall height (or length) of the bulging type is a little longer, which I think would be better, because there would be more contact surface between the threads. There is no side-to-side restriction for the bulging lug nuts to fit the steel wheels.
I searched the internet but found only that the lug nuts are 12M x 1.5. There was not mention of any other specification, and there was no mention of any difference in lug nuts between aluminum wheels and steel wheels.