Technical Studs Keep Shearing Off!

Well it looks to me as though there are several threads showing below where the studs broke. It will be interesting to find out what the OP decides.

 

No the center hole does not fit snugly on the center register. At this time only the lug nuts center the rim.

 

There you are, the wheel isn't designed to center on the lug nuts. The register locates the wheel and support it, the nuts hold the wheel, the wheel is actually held up by the register in the middle. There are companies, Wilwood Brakes for example, that offer machined adaptors that will fill the void and fix the problem.

 

No, they don't, which is the issue.

 

Now you get to either try all four rims on the offending drum or do some measuring....I'm betting some previous owner replaced a worn out drum with an incorrect drum and that is why your studs shear.I bet you will have to replace the drum.

 

It is not the drum it is the hub that is wrong, as the drum has to register on the hub as well as the wheel

Like I said 2 times replace the hub & drum , very simple you just need the right one like is on the other side so you could use it for a sample making sure you get the correct one

Do you have any Veneer calipers then you can measure those holes and know what you have, just buy a cheap pair from Harbor Freight cause they are very handy for checking lots of stuff

 

Had a chevy p/u that would do it with some white spoke wheels but after I put cragars on it never again.

 

I had some talley on my last 54. Had to put washers to move the wheel out just a touch to be able to tighten the lug nuts down. It was the center hole was a bit small for the huge hub. Used thick fender washer.

 

You are right hub and drum....not just drum.

 

Yes from what I see in the pic the drum bells out as it gets closer to the hub judging from the wear circle around the bearin snout the the outer wear circle looks as it is bearly contacting the drum , so I say the wheel is bottoming on its I.D. Before it is able to sit completely flat on drum surface allowing wheel to work just enough to shear studs

 

http://vid58.photobucket.com/albums/g275/plowboy13/Mobile Uploads/20150811_153729_zpsedhabqbu.mp4

 

I believe that the video bears this out.

 

The quickest and dirtiest fix might be a thin wheel spacer under that wheel. Give the wheel a seat to tighten against. Or open up the center hole in your wheels. Or the best would be finding a hub and drum that fits your new wheels. Or even, go back to the wheels that worked fine. Get some Moon disks and be happy.

 

Gonna stop at Tops Auto in the morning and get a drum first. I'll try it with my old hub.

 

Sounds like it was warped. You mustve had some kind of shimmy while driving or braking. Maybe some idiot in the past used an air impact to tighten the lugs one day. I think a new drum will solve the issue.

 

The practice of the hub centering (registering) the wheel didn't begin until after this car was built. There were MILLIONS of cars built that have only the studs registering the wheels, and they aren't breaking studs.

Notice that his hub has a cast finish on the snout. How could a wheel accurately register on that?

 

In a perfect world all OEM wheels would be hub-centric and all OEM hubs would fit all wheels. But, that is not the case and almost all aftermarket wheels, unless ordered hub-centric to your hubs, are stud-centric. That works well as long as:
1) the drum sits correctly on the hub
2) the wheel sits correctly on the drum surface
3) lugs nuts are torqued to proper values in the proper sequence

I do not believe this problem is a hub-centric vs. stud centric problem but a specific hub or drum or wheel problem not allowing the wheel to nest properly.

I have been doing this hot rod thing for more than a few and have never had a problem with stud centric wheels. That is not to say that a concentric ring to make a wheel hub centric is not a good idea. It is, but in most cases it is not necessary.

Lots of good suggestions but the OP needs to work through the issue in a methodical manner eliminating the source. Give him time.

 

So after I drill out the three rivets and remove the hub from the old drum, does the new drum essentially float on the hub? Providing it snugs down over the center bearing housing (register) anyway?
Guess what I'm trying to ask is do I need to replace the drilled out rivets with anything? Or are the lugs holding the wheel on sufficient?

 

Thats how the earlier (6 stud) Chevy hubs were set up as well, when you replaced the drum you would drill out the rivets, remove the old drum and just slip the new drum over the hub.
The wheel nuts would hold everything together.

 

I don't know where the terms hub-centric and lug-centric came from, but I assume they were invented by the aftermarket as some high tech sounding horseshit. In the auto industry, the terms are stud piloted and hub piloted, and its been that way since forever.

How to tell the difference is real simple. Any wheel that uses conical lug nuts is stud piloted. Hub piloted wheels have straight thru lug holes and use 2 piece lug nuts with a captive washer made onto the nut.

If an aftermarket wheel using cylindrical shank lug nuts, like Appliance slots for example, is mounted on a hub that used conical seat lugs from the factory, its still stud piloted regardless of how the center hole might fit on the hub. Among the wheels and hubs any of us are likely to encounter on a car, there are essentially zero wheels that are hub piloted. The most common place you would see an actual hub piloted wheel is on dually pickups.

The only reason the hub is a fairly close fit on the center hole of a stud piloted wheel is for convenience in mounting the wheel. It allows the stud holes to be fairly well centered on the studs so you aren't using the taper of the nut to drag the wheel into position. The center hole could be a quarter inch bigger than the hub pilot and it'll still mount just fine even though you might have to lift the wheel a bit to snug up the first couple of nuts.

Regardless of the type of pilot, and regardless of the fit of the center hole on the hub. the vehicle weight is not carried on the center hole of the wheel or the pilot diameter on the hub. Weight is transmitted from the wheel to the hub via the clamping force of the huts against the face of the hub or drum. Spacers, regardless of whether they're machined from steel or molded from plastic, sold to take up the space between a hub and an oversize center hole are nothing but a marketing gimmick to remove money from your pocket.

Back to the OP's problem....... the video clip shows something definitely isn't right with the hub/drum assembly. One thing that's important to mention is if a couple studs break from a mounting problem then all those studs should be replaced. The studs are breaking due to short cycle fatigue from cyclic loading, and you can never assume the rest of the studs weren't subjected to the same load cycling. They just weren't the first ones to break

The studs are breaking due to inadequate tightening. If a properly designed bolted joint is sufficiently tight, the bolts never see any load variation during operation because the preload is greater than the externally applied load. When the bolts are not sufficiently tight to produce the necessary preload, the tension in the bolts (or studs) is varying continuously. That load variation is the quickest way ever to cause fasteners to fatigue and break..

When I was working in R&D for a major tire manufacturer, we were running about 25,000 highway test miles per day on passenger car tires. Tires were moved from car to car twice a day at the end of each shift to make sure we weren't getting a wear effect from the car itself rather than from the tires. We torqued lug nuts to 75 ft-lbs for 7/16 studs and to 90 ft-lbs for 1/2" studs, and never lost a wheel during the ten years I worked there.

Lug nut torque values are given for clean and dry studs and nuts. If any sort of oil or never seez is used, those values or any values given by a vehicle manufacturer go out the window. Some lubricants require the torque to be reduced by as much as 50% to avoid overloading the studs. Clean and dry is the most foolproof method to use on lug nuts.

 

First thing, measure the center of the hub with calipers then the wheel to see whats going on. You've move the wheel back and used another. Compare left hub to right hub, if ones been replace the center could a bit larger or smaller.

The shine of the hub, shows the wheel to be walking around, not riding the center of the hub and flat against the drum.

It's a pain but pull the hub and have the studs pressed in. If your using nuts and washers to pull the studs in the hub you can damage the stud and sub grade/questionable quality studs compound this problem.

By changing the wheel placement, you've shown it's a problem with the hub or studs.

A smaller hub center would allow all the weight to ride on the studs.

With a small wheel center you should see a bit of a wobble or run out when you spin the wheel and tire.

 

Well the young man on the phone from the parts store was mistaken. They did not have my drums in stock. Will need to source them again.......

 

Any issue with just doing a bit of filing on the area it's hanging up on?

 

Regardless of hub centric vs stud centric......he's got the same wheels on 3 other of the same hubs and no issue. Its this specific one. The hub/stud argument is not the issue.

That specific drum is warped. Replace it and see what happens.

 

Truth. Back in college I did an experiment for an automotive engineering class where I measured bolt preload with a strain gauge at different torques. Pretty boring, every thing working just like the text book said -until I put some WD40 on one. Then I tried water, grease, oil...pre-load was all over the place. My prof didn't believe the results and gave me a "C" -story of my life.

Kelvin

 

Replace the hub and the drum. The wheel should sit flat without rocking.

Quoting this in bold because it's important, and it has been previously (and incorrectly) posted in this thread to lubricate the threads.

 

G'day, My first hot rod was a 55 Chevy and I put chrome steel wheels on it. I promptly broke the wheel studs off first the right wheel and then the left. The left wheel did considerable damage. A friend stopped by and was taking a look at the damage and asked my why I had not taken the rivets off. The rivets prevented an aftermarket wheel from seating flat on the face of the drum and shears the studs.

He took a hammer and chisel, knocked off the rivet heads and I drove thousands of trouble free miles after that.

 

While the torque specs are for new studs and nuts installed dry, only install them dry if you plan to remove them the following day or never want to remove that fastener again! A rusty stud and nut requires higher torque to obtain the same clamping force.

I've too often had the task of trying to remove wheels that had the nuts installed without lubrication and are rusted solid. They either have to be heated, which ruins the wheel and the stud and nut, or hope the stud breaks off without spinning in the hub or axle. If the stud turns in the splines, the hub or axle will need to be replaced.

There's nothing as maddening as being out on the side of the road on a service call at night trying to change a tire that some idiot installed without lubing the studs. We had a 3/4" drive ratchet set with a 6 foot pipe extension handle to try to remove these. It's a reason that we always took the wrecker on flat tire calls as it often resulted in towing the vehicle in.

The preferred way to install studs is to press them in but many have been installed using the nut and a stack of well lubed washers. A ball joint press can sometimes be used to avoid removing parts to press the studs in.

 

Well I was able to get a replacement drum from my friend Todd at Walton Fabrication, and it mounts up to the rim very nice. Also got rid of the push throught center caps in favor of spyder caps. First test drive today-will see how it goes!!!

 

Good luck Bob!