Wheels cracking x3

[c4clewis]

Has anyone ever seen a wheel crack like this? This is the 3rd wheel I've had this happen to now.

Trying to upload the photo, but can't seem to find a way to do it. I think I'm paid up!

https://drive.google.com/file/d/0B7RI2LX6aFLSeWhSTVJvaFhOWE0/view?usp=sharing

Coker took the last one back after I told the rep this was the second one to do it, and they have not heard of any problems.
The failures are always on the front wheels, I'm wondering if it's the weight.

Any ideas from the gallery?

[jopizz]

I've never seen a factory wheel crack so it's either poor materials or bad craftsmanship. There's certainly a lot more torque on the front wheels because of the weight. Your picture is not showing up so I can't see exactly where it's failing.

John

[Tbird1044]

Looking at the cracks and their pattern, it makes me wonder if the hole in the center of the rim is large enough to register on the drum and not cause the wheel to create stresses if not. Are your cracked rims always from the same wheel position? I'd seriously look at the mounting surface where the wheel is bolted to.
Nyles

[YellowRose]

Wheels cracking x3

Your Paid Membership expired on 5-28-16. But the first link to the picture of the cracked wheel worked for me. The second one did not, so I took it out, downsized the pic and put it in for all to see.

[c4clewis]

It has been both front wheels that have failed. I am running disc brakes up front, so the wheel does not have an interference-type fit against the center like the factory drums, instead it lays flat against the disc.

I checked both flatness and runout on the hub. It is as flat as my metal straight-edge and runout is less than .015 on both sides.

I'm running as large a tire as I can fit at 16x8 with a 4.5" backspace on Coker chrome smoothies with wide-whitewall radials.

https://www.cokertire.com/smoothie-wheel-chrome.html

I'm giving Coker a call tomorrow (since I won't be at the car show) to see if they saw anything on the wheel that I sent back to them, but I doubt it.

P.S. @YellowRose, I paid up! I seem to lose track of the membership until I try to post a picture or something.

[bird 60]

Hi Mat, from what I can see the cracks are where the bolts are.
I could be wrong but they could be over-tightened. Also are you sure they are the right wheels for the car?

Chris....From OZ.

[JohnG]

for the heck of it, with the wheel off the car, see if you can get a caliper on the wheel, perhaps using the center hole, and see approx how thick the metal is, then compare with a factory wheel. See if there is a substantial difference.

All those bolt holes certainly don't do anything for the strength. Guess it is to allow their wheels to fit more cars - one size fits all.

Did you use a torque wrench when installing?

I would also want to make sure that the contact area between the rim and the brake rotor (you have disks, right?) was appropriate, meaning that as the lug nut is tightened, the rim is not being distorted by being sucked toward the rotor. In other words, it should contact the rotor before the lug nut is ever tightened, to avoid unecessary stress. Since you have all those extra holes, perhaps you could sneak a feeler gauge in and see if there is any gap . . . just my thought. If it turns out there is any kind of spacing prior to the lug nuts being installed, the problem might easily be solved with some appropriate washers on the studs, followed by the rims.

Personally, I would be appalled if these were mine.

[partsetal]

Every OEM wheel I've seen has a sharp flange around the hub opening. I don't see one on this wheel. Perhaps this is the reason the OEM's include it.
Carl

[c4clewis]

Chris,
I didn't put a torque wrench on them, but I tighten them by hand with a star wrench like I have on every-other vehicle I have had without a problem before. I can put on the torque wrench and see if I have gotten hulk strength as I've gotten older!

John,
I am appalled. I have contacted Coker and they will be getting back with me on Monday. I'll have to check for any gaps, but they "feel" like they are seating when I go to tighten them up.

[c4clewis]

John, I think you nailed it!
I checked the torque, and I guess I've got the calibrated arm, all were 90-100ftlbs.
However, I checked behind the good rim like you suggested and there is space. It looks like just the outer edge is contacting the hub and it is indeed getting pulled in.
Now, what's the fix?

[JohnG]

I would visit the hardward store and come back with a bag of washers and go from there. Just enough to take up the gap. Proabaly 1 or 2 might do.

Looking at your original photo, the cracks seem to be beginning at the lug hole. (or someone else might say that they end there, but I don't think so) suggesting alot of stress there.

I actually asked about the torque as there is a school of thought that suggests if lugs nuts are under torqued, there can be play which results in cracks. Not your problem!

do you still have 1 or 2 good rims to work with?

[KENN]

Are The Holes Tapered(beveled) For The Acorn Nuts?

[scumdog]

Obviously there is some sort of mechanical/physical thing going on with the hub/rim however as with all things that have been chromed you have the risk of hydrogen embrittlement causing cracking, just something else to consider here.

[simplyconnected]

...as with all things that have been chromed you have the risk of hydrogen embrittlement causing cracking, just something else to consider here.

Modern thinking includes using 'high-strength' alloys, then they reduce the thickness to save (unsprung) weight.

My observation is that the crack is from flexing away from the lug holes, then it spiders once it migrates to the lug nut holes. The widest portion of the crack indicates the most flexing.

The clean portion of the rotor bears witness that the lug nuts kept the wheel tight against it. I would use bluing ink on the lug holes to see if the nut cones contact the entire diameter of the holes. It appears they are centered properly but it's worth checking. Conical nuts must be torqued in steps and in a cross-pattern to ensure proper centering. We haven't used the center hub for wheel centering in years because FOUR nuts will do the job, save five (ala, the 1990 Mustang w/HO or 351W engine).

All wheels flex, or they would break from being too brittle (hard). Proper alloy and heat treat allows toughness and flexing, at least it has for many decades. No steel wheel should crack. Also check around the welds because failed welds could cause excessive flexing. - Dave

[Yadkin]

Those wheels are defective and dangerous. Get your money back