2nd Gen Non-Engine/Transmission "Conversion lug nuts?"

[BDaugherty]

I'm helping a friend put some aluminum wheels off a 2500HD Chevy on his 95 Ram 2500. I used a router to open up the center holes and make the wheels fit. Now he wants to use the stock Chevy center caps, but I'm not too sure what the best way is. I've been looking around and it seems that the GM's use M14x1. 5 studs while to old Dodge uses 9/16-18. Leaving out any bias about why he would want to use GM parts on a Dodge, does anyone know where I could get lug nuts with the correct thread on the inside that would also have threads on the outside for the center caps to screw onto? If it makes anyone feel better, the Dodge had trashed/old/ugly aluminum wheels on it with way too much offset when he got it and the GM wheels were a great price with good tires already on them.

 

[HHhuntitall]

Yeaaaaaahhhhhh... ..... about that..... I'm not sure that's gonna work too swell. Those lugnuts are exclusively GM, and have been metric since the concept of their wheel covers. The only thing I can think of that will work is to hammer out your studs and install Metric 14mm studs, instead... ... . Or see if a machine shop can clone them for you, using some bar stock or other quality metal, and then thread with the 9/16. I'm not sure there is enough difference to rethread the nuts to 9/16. You'd have to have someone measure them and see... . I don't have any around, but the 14mm is smaller than 9/16, so there's a possibility. Good luck.....

 

[Road Dog]

The studs are pressed on so you would need a machine shop to drill out the hub for the GM studs.

As an aside, Dodge wheels are mounted hub-centric so the center hole should be be perfectly centered and perfectly round.

 

[BDaugherty]

Yeah. I know it will work fine using the acorn lug nuts currently on the truck, but I was hoping to find something that was already 9/16-18 on the inside and had some sort of threads on the outside. As a last resort, he can run it using the old center caps or even without.

Another thought that I entertained: The current lug nuts are the extra tall ones so I don't think they will clear to caps. But all I have to do is rig some way to hold the caps on while using regular acorn nuts. Maybe use a couple of smaller bolts into the wheel mounting surface like a lot of the aftermarket wheels use. Also, I thought about swapping the studs, but I haven't gone as far as measuring the shoulder of the stud where it presses through the hub flange. I was hoping for a cheaper option, but I guess if it fit right and made for a clean install it might be worth it. Maybe next week I'll take a dial caliper to the parts store and have them pull a couple studs for me to measure.

 

[HHhuntitall]

Ya know, thinking about this, don't those caps have bowties on em? Wouldn't it be easier, and better looking, to find some factory Dodge caps and snap them on over the lugnuts, covering the wheel centers, and eliminating this issue? Just my thought.....

 

[BDaugherty]

I will have to buy lug nuts either way because the current ones are the really tall kind that are completely closed at the end and he does already have the bowtie covers, but that might be much easier. What do you think, 2nd or 3rd gen covers? I bet I could get some from the junkyard or maybe even rock auto. Either one that fit would look fine as long as it was chrome to match. Great thought.

 

[HHhuntitall]

The 3rd gen caps for the chromed wheels will fit flush with the wheel, and I think the chevy wheel is pretty clean, with no lip or ridge, so I'd think 3rd gen..... or the early 2nd gen. And if you find the caps in the boneyard, they should have lugnuts laying everywhere, pretty cheap.

 

[BDaugherty]

I just found a set of lug nuts and center caps off the same year truck. I'll post something when I get the tires swapped and have it all together.

 

[BDaugherty]

Finally got around to messing with it. The factory '95 center caps and lug nuts won't work with the GM wheels. The factory wheels have are steel and have a raised area where the acorn of the lug nut fits. The raised area allows the ring on the inside of the center cap to snap over the shoulder of the acorn. The GM wheels are aluminum and are perfectly flat with a recessed taper for the acorn which keeps the center caps from being able to sit far enough down to snap over the shoulder.
I did discover that 9/16 is larger than 14mm by just a little, but I'm still not too sure about tapping 14x1. 5 threads into 9/16-18 on the inside of the lugs. I might try one and see how clean it comes out just as an experiment. Don't worry, if it isn't nearly perfect I won't trust it. Brakes, lug nuts, steering... pretty important. I may test out some of my 3rd gen caps. . but don't the AAM axles use metric studs, too? Hmmm. Time to tinker and experiment a little. One thing is the GM HD wheels look pretty sharp on the old Dodge with the bowties removed.

 

[HHhuntitall]

Ahhhh, why would you tap 14mm into a 9/16 nut? I would think you would tap the 9/16 into the 14mm nut so it would go on the standard dodge stud..... Then you could use the Chevy cap on the dodge studs, with the Chevy nuts... ... 14mm is slightly smaller than 9/16, so it SHOULD tap out correctly. There actually is not enough metal by industry standards, but it should work... ...



As for the Dodge center cap, I figured on using the later Dodge models, say 99 or later, that had 4 springed holding points. That would fit inside the rim, if I'm not mistaken..... JMO. Good luck.

 

[WalterRyan]

I would not tap the nuts. The pitch is not the same. The M14 X 1. 5 is . 059 between threads. The 9/16-18 is . 0555 between threads. What this means is that as you start the tap it will follow the first thread but the tap will be a little short of each thread. By the time you get to the end of the nut you will be almost a full thread behind. There are other differences between the shape of the two threads but I will not get into that. I will just say that after you finish you will probably only have about 1/3 of the original strength left. It may pull the threads before you get them torqued to spec.

 

[HHhuntitall]

No, and I'm in agreeance to a certain degree... ... Tapping with a 9/16 thread, the ideal theoretical hole size(according to one chart... . they don't all agree, but are all close) is . 5398 to . 5417. 14mm is . 551161. 9/16 is . 5625 If your 14mm threads are small, there is almost enought thread to do it correctly. The thread pitch won't matter, as you will be completely removing the 14mm threads. If they are on the large side... . you will almost be removing most of the 14mm threads... ..... which can lead to thread loss where they undercut each other, which can result in a weak lugnut... ... . :{



The only "safe" ways of doing it would be to take a 1/2" lugnut and drill it out to around . 54, and tap it 9/16, or else source some 14mm studs to go on the Dodge, and use the Chevy lugnuts... ... . That's just my opinion.....