[M2guru]

What brand are you running?
What torque?
When do you replace yours?
Related: How often do you hit the track within that time?
What tires (slicks/race or street)?
Any breakage?

[DrKevM5]

Motorsport Hardware. Torque to 140 Nm. https://Motorsporthardware.com. Replace yearly. I run 8-10 events a year. Never broke one in 20+ years, but they can back out, especially when removing nuts. DO NOT use impact wrench. Will cause the nut to cold weld to stud.

[M2guru]

Originally Posted by DrKevM5

Motorsport Hardware. Torque to 140 Nm. https://Motorsporthardware.com. Replace yearly. I run 8-10 events a year. Never broke one in 20+ years, but they can back out, especially when removing nuts. DO NOT use impact wrench. Will cause the nut to cold weld to stud.

Thanks for your response DrKevM5.
How many days is each event typically?
What tires are you using (g's are you pulling regularly)?
Standard 17mm or high-torque 19mm nuts?

[Track/S]

Titanium M14 studs with 19mm nuts
140nm
They have been installed for a year and a half
Around 10-12 events
Semislicks
0 issue

[F87source]

Originally Posted by Track/S

Titanium M14 studs with 19mm nuts
140nm
They have been installed for a year and a half
Around 10-12 events
Semislicks
0 issue

That's actually an incorrect answer.

Titanium studs are actually not ideal for track use due to a strength concern, grade m12.9 studs are a much better option. Titanium is much better for weight savings so roll racing applications.


The reason why this is true despite titanium having a significantly higher tensile strength to weight ratio vs. steel, is because it is strength to WEIGHT ratio. So for 2 similar mass pieces of metal, the titanium one is going to be much much stronger, but you must realize the titanium piece will be much bigger because it is lower in density you will need more of it to reach the same weight.


So when it comes to fixed sized objects like wheel studs, both the titanium and steel studs will be the same size. However, the steel bolts will be much heavier than the titanium bolts. So when you calculate tensile strength to weight, the steel actually will have much more tensile strength because it is significantly heavier. So for the same sized objects the steel option is stronger, this is why you see titanium bolts break on track but you don't see grade 12.9 steel bolts break at the same rate. You also have to factor in the titanium's grade and quality, and since most wheel bolts come from China, we don't see the greatest quality and we don't see the strongest grade of titanium in use. We generally see grade 5 titanium on most bolts, because that is the most common grade of titanium.

Here's a thread about this:
https://f80.bimmerpost.com/forums/sh....php?t=1356233



Now this relation ship between tensile strength and weight doesn't always have to favor the heavier object or lower tensile strength to weight ratio object, it just so happens that the delta between titanium's tensile strength to ratio vs. steel's tensile strength ratio wasn't large enough to make up the difference. But something like carbon fiber (a specific weave and grade of course) can make up the difference and then some, because carbon fiber has a ridculous tensile strength to weight ratio, to the point where it can be significantly lighter yet stronger than a steel part.




So in response to OP's question, you should get grade 12.9 wheel bolts such as motorsport hardware's wheel bolts: https://motorsporthardware.com/ I haven't seen anything better than these.

[M2guru]

Thanks for the responses to my question! I appreciate it!

The reason for asking this question is because I have been having stud problems. Twice within one year of being new, I had 1-2 studs break on my driver's rear. I found out when I went to torque them down by hand. I got to within 10-20 ft lbs and they kept turning until they snapped. I was wondering if it was just a driver's rear problem.

So I did some rudimentary testing by not replacing the other corner's studs. I was expecting to break them by torquing them down and breaking them just like first 2-3 studs. But that's not what happened. On Saturday, I found out the hard way by losing 4/5 studs all at once (or what seemed all at once) during a 70mph corner.

The studs that broke were about 17 months old (time doesn't really matter does it?) and 26 track days (actual days).

I mostly use slicks on the track and only street-drive the car to and from the track. I am relatively very quick on the track and often pull 1.2 to 1.33 g's. The curbs on my local track are not very rough. I use an impact wrench to remove the nuts, but put them back on by hand.

I am trying to figure out if I'll have better luck switching brands or if I should just replace them every year. If I need to replace them every year, the brand I am currently using seems WAY to close to barely making it one year and so I think I might like to try another brand.

Now that I've told you the full story (but not sharing the brand, yet)...any thoughts on this?

[Maynard]

The best solution is Core Motorsports stud replacement package. These are tru thru-hub studs like most other OEM's use, but in better hardware grade. More expensive, but the only real solution.

Second best for safety is to use factory bolts and replace them (yearly). Screw in studs have an inherent stress riser at the mounting hub. No way to get around it, all you can do is replace them on schedule and hope for the best (having lost studs on 2 rear wheels, I'd think you are using up your 9 lives rapidly). If you do use studs, use the best race quality you can get and replace them regularly (many are just for show, or just for adding spacer plates).

[Track/S]

Originally Posted by F87source

That's actually an incorrect answer.

A lot of bible bro....

motorsporthardware use 10.9grade not 12.9.

I already talked about 12.9 a long time ago.

Originally Posted by Maynard

The best solution is Core Motorsports stud replacement package. These are tru thru-hub studs like most other OEM's use, but in better hardware grade. More expensive, but the only real solution.

Where are the bmw motorsport parts that remove all other brands.

M4 GT4 studs or M2 CSR, they are expensive but they have a reason.

[OG Shark]

Originally Posted by M2guru

Thanks for the responses to my question! I appreciate it!

The reason for asking this question is because I have been having stud problems. Twice within one year of being new, I had 1-2 studs break on my driver's rear. I found out when I went to torque them down by hand. I got to within 10-20 ft lbs and they kept turning until they snapped. I was wondering if it was just a driver's rear problem.

So I did some rudimentary testing by not replacing the other corner's studs. I was expecting to break them by torquing them down and breaking them just like first 2-3 studs. But that's not what happened. On Saturday, I found out the hard way by losing 4/5 studs all at once (or what seemed all at once) during a 70mph corner.

The studs that broke were about 17 months old (time doesn't really matter does it?) and 26 track days (actual days).

I mostly use slicks on the track and only street-drive the car to and from the track. I am relatively very quick on the track and often pull 1.2 to 1.33 g's. The curbs on my local track are not very rough. I use an impact wrench to remove the nuts, but put them back on by hand.

I am trying to figure out if I'll have better luck switching brands or if I should just replace them every year. If I need to replace them every year, the brand I am currently using seems WAY to close to barely making it one year and so I think I might like to try another brand.

Now that I've told you the full story (but not sharing the brand, yet)...any thoughts on this?

Do you retorque during the day / in between sessions?

[medphysdave]

Which of the online BMW retailers can sell the BMW motorsports products? Mine can order the CSR wheels, but can't get the sway bar. I didn't insist or get into a VIN conversation. Buying local saves on shipping.

[M2guru]

Originally Posted by OG Shark

Do you retorque during the day / in between sessions?

I do not. Was about to start doing it right before a session when they are cool.

[Track/S]

Originally Posted by medphysdave

Which of the online BMW retailers can sell the BMW motorsports products? Mine can order the CSR wheels, but can't get the sway bar. I didn't insist or get into a VIN conversation. Buying local saves on shipping.

If you have trouble getting it I can send you one.

[medphysdave]

Originally Posted by Track/S

If you have trouble getting it I can send you one.

Thanks!

[F87source]

Originally Posted by Track/S

A lot of bible bro....

motorsporthardware use 10.9grade not 12.9.

I already talked about 12.9 a long time ago.




Where are the bmw motorsport parts that remove all other brands.

M4 GT4 studs or M2 CSR, they are expensive but they have a reason.

It's not bible, it's material science.

If they don't sell grade 12.9 hardware then what's this? https://motorsporthardware.com/produ...-14x125-14x15/

[Track/S]

Originally Posted by F87source

It's not bible, it's material science.

If they don't sell grade 12.9 hardware then what's this? https://motorsporthardware.com/produ...-14x125-14x15/

Yes, a lot of bible and little practice in real life.

I entered the page and clicked the first studs I saw, for m12 they make 10.9 and for m14 12.9, a bit strange....

[Daytona_550]

I use these 12.9 grade https://motorsporthardware.com/produ...ose-stud-kit/, and replace them every two years. 3-4 events per year, 6-8 track days. Thread by hand and torque per instructions. Torque nuts at 140Nm, only when cold. RE71 street tires. No trouble to-date.

[F87source]

Originally Posted by Track/S

Yes, a lot of bible and little practice in real life.

I entered the page and clicked the first studs I saw, for m12 they make 10.9 and for m14 12.9, a bit strange....

Little practice in real life, lol.... I guess you don't understand how engineering works then, because every single part of engineering a car references this "bible" material you speak of. It is impossible to engineer a part without the fundamental science.

[Track/S]

Originally Posted by F87source

Little practice in real life, lol.... I guess you don't understand how engineering works then, because every single part of engineering a car references this "bible" material you speak of. It is impossible to engineer a part without the fundamental science.

I don't have time or desire to be reading bibles, I could write 3.

[dvas]

Originally Posted by M2guru

Thanks for the responses to my question! I appreciate it!

The reason for asking this question is because I have been having stud problems. Twice within one year of being new, I had 1-2 studs break on my driver's rear. I found out when I went to torque them down by hand. I got to within 10-20 ft lbs and they kept turning until they snapped. I was wondering if it was just a driver's rear problem.

So I did some rudimentary testing by not replacing the other corner's studs. I was expecting to break them by torquing them down and breaking them just like first 2-3 studs. But that's not what happened. On Saturday, I found out the hard way by losing 4/5 studs all at once (or what seemed all at once) during a 70mph corner.

The studs that broke were about 17 months old (time doesn't really matter does it?) and 26 track days (actual days).

I mostly use slicks on the track and only street-drive the car to and from the track. I am relatively very quick on the track and often pull 1.2 to 1.33 g's. The curbs on my local track are not very rough. I use an impact wrench to remove the nuts, but put them back on by hand.

I am trying to figure out if I'll have better luck switching brands or if I should just replace them every year. If I need to replace them every year, the brand I am currently using seems WAY to close to barely making it one year and so I think I might like to try another brand.

Now that I've told you the full story (but not sharing the brand, yet)...any thoughts on this?

I twice had a very similar experience to you using Apex studs....Good track wheels, perhaps the studs are better utilized on the street only.

Twice I snapped a driver's side rear stud while torquing the wheels in the morning. Both times, the studs were just shy of two years with a total of roughly 20 track days, mixed as is typical between wet and dry. I was told and hoped that they should last a full two years and at least 30 days. I had installed the first set of studs per Apex instructions while a race shop installed the second set. Didn't notice any issues with them until they snapped.

I run a square setup on NT01s with 12mm spacers up front and 5mm spacers in the rear. I have always run this car with full driver aids off, DCS and ESC. I only torque in the morning prior to the first session and don't torque again unless I take a wheel off for some reason. In terms of pace, I run sub 1 minute at LRP and 2:10 at WGI on good days with a manual OEM powered OG M2.

I have since switched to Bimmerworld motorsport studs on the recommendation of a BMW race shop. This coming September will be a full year, so the jury is still out on how long the Bimmerworld studs will last. Interestingly, Apex had recommended factory torque specs which is ~103 lbs while Bimmerworld recommends 70lbs on theirs.

As a side note, I always change all the suds at all four corners once I see an issue with any single stud. Saw an E92 M3 end up upside down in the carousel at WGI when this rule wasn't followed.

[M2guru]

Originally Posted by dvas

I twice had a very similar experience to you using Apex studs....Good track wheels, perhaps the studs are better utilized on the street only.

Twice I snapped a driver's side rear stud while torquing the wheels in the morning. Both times, the studs were just shy of two years with a total of roughly 20 track days, mixed as is typical between wet and dry. I was told and hoped that they should last a full two years and at least 30 days. I had installed the first set of studs per Apex instructions while a race shop installed the second set. Didn't notice any issues with them until they snapped.

I run a square setup on NT01s with 12mm spacers up front and 5mm spacers in the rear. I have always run this car with full driver aids off, DCS and ESC. I only torque in the morning prior to the first session and don't torque again unless I take a wheel off for some reason. In terms of pace, I run sub 1 minute at LRP and 2:10 at WGI on good days with a manual OEM powered OG M2.

I have since switched to Bimmerworld motorsport studs on the recommendation of a BMW race shop. This coming September will be a full year, so the jury is still out on how long the Bimmerworld studs will last. Interestingly, Apex had recommended factory torque specs which is ~103 lbs while Bimmerworld recommends 70lbs on theirs.

As a side note, I always change all the suds at all four corners once I see an issue with any single stud. Saw an E92 M3 end up upside down in the carousel at WGI when this rule wasn't followed.

You and I are very similar in setup, steps and experience. Since almost dying last weekend but somehow being saved by a lone Jesus-stud, I am going to be replacing studs every year or 25 track days, whichever comes first. I will be changing brands because I don't have confidence that the brand I was using will go a full 25 track days.

[PackPride85]

Titanium studs are a giant waste of money. They are equally as strong and lighter but present their own issues with galling and questionable quality. Get high quality steel ones like MSI and replace every season if you track a lot.

[E90convert]

Originally Posted by Track/S

A lot of bible bro....

motorsporthardware use 10.9grade not 12.9.

I already talked about 12.9 a long time ago.

I agree. Please use 10.9.

If you use 12.9 there is a risk of hydrogen embrittlement that is further sensitive to certain fastener coatings and hardness of the fastener. With the right conditions, your bolt will fracture within a few hours up to a few weeks after tightening.