Hi again, lug nut question

[Xzael]

Hey guys, I know I have asked a bunch of questions here and I appreciate all the answers. Once I get everything (rims, tires, exhaust) all ready on my car I'm gonna post my experience with everything and what I put on there.

My problem right now is that my car (2001 Trans Am WS6) is at the mechanics now, I have the exhaust, tires, and rims. The exhaust was put on and the tires and wheels together and balanced, but when I bought the rims they didn't come with lug nuts!

So I've been hopping from store to store asking what the hell I need for this rim and no one knows! These are after market rims I bought, Z06 replicas.

What the mechanic told me so far is that:

The rims are:

Size: 18x9.5 inch
Bolt Pattern : 5x120.65mm (Same as 5x4.75)
Offset/ET: 57 MM

The lug nut isn't an "acorn" style, its a "shank" style. The lug nut is supposed to fit through the opening of the hole. The hole, or rim, is 9/16ths thick. The lug nut size is "M12 1.5". He said it should be like 1/2 inch long, or 3/4 inch long if it has a washer with it. Which is another problem because no one knows if there should be a washer with it. And if it needs a washer, what thickness and size it should be. I was told if there's no washer though that it would ruin the rim.

I'll post a picture of the rim in a second if I can. Any help would be appreciated.

[Xzael]

Here's the pics guys

[Trash man]

looks like u need a shank or shoulder type lug nuts. i think jegs or summit has them but make sure u get the right length, go a lil shorter (like a toyota pick up has these style lug nuts on the alloys) that way they dont bottom out be4 the rim does. otherwise u will have major issues down the road. yes get the washer that actually helps hold the wheel on. look up toyota lug nuts, they might have the size u need

[Gary94Formula]

Check local auto parts stores. You might be able to find them as they usually sell those style lugs nuts for the old Uni-lug wheels. Just make sure they have the correct depth and shoulder area to hold the rim tight.

[Mark B]

Are those type lug nuts lug-centric? I know the acorn style ones are. If those arent, you need to make sure that the wheels are hub-centric.

[4THGEN Z]

I am suprised that style of rim doesn't use cone or acorn style lugs but anyway here is a site that shown the different shank lengths available..

Shank lugs

[Xzael]

You guys aren't gonna believe this lol...

So after much searching around, apparently what I need is a shank style, flat seated lug nut with a 12mm X 1.50 thread size. Since the hole depth is 9/16" I need a 12/16" (3/4") long shank and a 3/16" thick washer to go with it so it fits properly. This isn't a problem:

http://www.gorilla-auto.com/products...image=5245.jpg

Now here's the kicker...

The standard shank diameter, no matter which company that I check, is 0.685".
This rims have a 0.625" diameter.
Result? I have to take the rims to a machine shop to get the holes bore'd out bigger so they can fit the standard size lug nut!

I bought them off ebay, and I called the guy who was chineese, and asked if I could have the manufacturer of the rim to ask them the exact make and size of lug nut hat will fit my car. He said "You don't need to know." then when I insisted, he said "They're in china, what are you going to call them? They won't understand you."

But yeah, that's gonna cost me $140 to get the holes bore'd out, and if they screw up just one rim, the rest are pretty useless!

[Blazer]

Sell them back on E-bay.End of problem.
Blazer

[Injuneer]

Did you verify that the bolt circle is in fact 4.75" (120.65mm)? They may have been made for something like a BMW with a 120mm bolt circle. When you are having the holes bored out, make sure they put them on the correct diameter circle.

[Xzael]

Did you verify that the bolt circle is in fact 4.75" (120.65mm)? They may have been made for something like a BMW with a 120mm bolt circle. When you are having the holes bored out, make sure they put them on the correct diameter circle.

What's a bolt circle?

[Trash man]

measurement from one lug to the other. in this case, its between two, on at the bottom and one at the top, measure from top of one of the lugs to the middle of the top on a 5 lug car. ill try to find a picture



edit: heres the picture

[Xzael]

Oh yeah... we're already put the rim on the posts and it's fits... just need the lugs

[Xzael]

Okay so i got the lugs on, after a while they became loose though, is this normal for new lugs to do that? Do they need to be "worn in"? They're Gorilla Lugs so they're good quality.

I should probably also mention that there's only 4 lugs in right now (the rest come tomorrow, would that do it?

[Injuneer]

That's an "approximate" way to measure the bolt circle, but its not the correct definition. The bolt circle is the circle that the centerpoints of all the lugs are located on.

Fitting the wheels by slipping them over the lug nugs will not tell you if they have the correct bolt circle, particularly with the holes in the wheel being so oversize for the shank style lugs. We are only talking a tiny difference 120.00mm vs 120.65mm. The shop that drills the holes has to insure that they drill the holes on the correct bolt circle diameter, and that the bolt circle is perfectly concentric with the centerline of the wheel. If they are "off", the wheel will mount lopsided on the lugs, or the lugs will force the studs to deform, subjecting them to bending stress, in addition to the normal shear and tensile stresses.