What stud conversion is every one running

[bjz!]

I've used Bimmerworld, Turner, APEX, and Vorshlag. I've never hand an issue with a Vorshlag or Bimmerworld stud. Except for BW's ridiculous instructions to install the stud into the wheel hub and torque to 70 ft/lb.

My buddy has had 2 sets of turner studs break. I had an Apex stud break after 6 months.

I stick with Vorshlag just from my personal experiences.

In my e36 i have apex studs, since they start the company atleast and, 0 problems. What melodramatic the people.

[CrookedCommie]

In my e36 i have apex studs, since they start the company atleast and, 0 problems. What melodramatic the people.

Tell me you've never lost a wheel on track without telling me 😂

[Tbonem3]

Ya, I think the stud thing is overblown like everything else. I really don't understand how m12x1.25 stud is any much different than a m12x1.25 wheel bolt.

I've got 5 years & 9k on my apex studs. If it's a track car, I see the point in annual replaacement (if you go 10/10, over curbs, every month or multiple days per month), but I'd also then say to get new wheel bolts too.

[CrookedCommie]

Stress risers on the shoulder where the threaded stud meets hub cause eventual failure. It's not an if it's a when.

Street cars are probably fine on any wheel studs, track and race cars should look at either MSI or core4.

[George Hill]

Why are screw in studs inferior....

https://www.core4motorsports.com/tech

[Tbonem3]

Stress risers on the shoulder where the threaded stud meets hub cause eventual failure. It's not an if it's a when.

Street cars are probably fine on any wheel studs, track and race cars should look at either MSI or core4.

Looks like my studs have extra material where the studs meet the hub face - wonder if that helps? A wheel bolt enters and sits in the rotor/hub the same as studs do, so why wouldn't a wheel bolt be subject to the same "stress risers"?

The difference I do see is a second point of fastening, which is the nut on the stud whereas a wheel bolt head is a part of its stud. Simpler is better.

And I think one of the most important factors is to never touch the lug (bolt or nut) when hot. Undo or check torque only when cool.

[CrookedCommie]

The problem is exactly that, the extra material where the stud meets the hub is there because it's a threaded stud, but it expands and contracts at a different rate than the hub, and gets repeatedly stretched until failure. Look at the picture George linked above you can see they will snap right at the shoulder. MSI somewhat alleviates this by having that shoulder be cone instead of flat to meet the hub, but it's a band-aid. Pressed in studs don't have this issue, and should last as long as the wheel bearing does, at which time they can be serviced again.

[Tbonem3]

Got it. What about a stock wheel bolt - why is not subject to the same stress? Or it is, and you would also say to change stock wheel bolts annually as well?

[CrookedCommie]

The bolts don't develop the same stress risers as it's a straight fastener between the wheel face and the hub - no shoulder. With enough stretch cycles (think torquing the wheels), they too will need replacement, but the time frame is much longer.

Hopefully I've explained it correctly, I'm not a mechanical engineer, Tom from core4 is and we've had some lengthy discussions. I've been snapping these things for a decade, last endurance race I drove ten studs and a damn wheel off the car 😂

[Tbonem3]

Ya no worries. It doesn't seem to be intuitive though - I would assume extra material (shoulder you call it) would increase strength, not lead more quickly to stress/failure. Wonder if that means that a stud with no shoulder (just threaded the whole way through) would be equal to the stock wheel bolt?

Either way, like most stuff, make your decisions based on the car's usage...

[bigjae46]

I have never lost a wheel. Although every time a car loses a wheel on track...it has been a BMW. I remember I asked why the track was shut down. My buddy told me a car lost a wheel. I said, "It's a BMW". He was like how do you know that? And....a silverstone E92 M3 on the flat bed with 3 wheels.

I've seen studs and lug bolts fail. It comes down to taking care of them. Stuff like dragging the wheel over the threads, torqueing and then re-torqueing, over-torqueing with a long torque wrench, and not keeping the mating surfaces on the hub and wheel clean.

[George Hill]

I have never lost a wheel. Although every time a car loses a wheel on track...it has been a BMW. I remember I asked why the track was shut down. My buddy told me a car lost a wheel. I said, "It's a BMW". He was like how do you know that? And....a silverstone E92 M3 on the flat bed with 3 wheels.

I've seen studs and lug bolts fail. It comes down to taking care of them. Stuff like dragging the wheel over the threads, torqueing and then re-torqueing, over-torqueing with a long torque wrench, and not keeping the mating surfaces on the hub and wheel clean.

Was this a couple years ago at a texas track? Likely my clients car that I am literally putting Core4 hubs on today.

[M9Seth]

I opted to use the Core4 Motorsports bolt through MSI studs. I was in the process of replacing my wheel bearings anyways and sent them my new front and rear hubs. This bolt-through design eliminates the failure point in the standard design and these same studs are used in NASCAR.

On a side note, what is is the highest quality stud nut on the market?

I too am using Core4, they also manufacture lug nuts, pricy but worth it. https://www.core4motorsports.com/pro...core4-flug-nut

[elbert]

The problem is exactly that, the extra material where the stud meets the hub is there because it's a threaded stud, but it expands and contracts at a different rate than the hub, and gets repeatedly stretched until failure. Look at the picture George linked above you can see they will snap right at the shoulder. MSI somewhat alleviates this by having that shoulder be cone instead of flat to meet the hub, but it's a band-aid. Pressed in studs don't have this issue, and should last as long as the wheel bearing does, at which time they can be serviced again.

Another key difference is "12mm press-in studs have 44+% larger cross-sectional area at points of peak stress at the hub than thread-in studs and bolts"

[eacmen]

I doubt you guys take almost half bad back roads and put tyres outside the tarmac like me, and, still 0 problems. So, stop being dramatic about studs, thanks.

Wow. You’re braking hard from 140 to 60 and taking over 1G lateral over and over again on back roads? Where is this amazing piece of tarmac? I need to experience it.


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