Track forum general chit chat.

[Move Over]

Originally Posted by dparm

It's a good observation but I would be shocked if Core4 hadn't already thought about this.

Tom called me, he said the splines from the stud spline cut the hub as it is pressed in, the hub is a softer metal than the stud.

[derbo]

Originally Posted by Move Over

Tom called me, he said the splines from the stud spline cut the hub as it is pressed in, the hub is a softer metal than the stud.

so, when you replace the press-in studs, one would hope the splines just line up with the carved out hub?

[fsmtnbiker]

Originally Posted by derbo

so, when you replace the press-in studs, one would hope the splines just line up with the carved out hub?

Yeah, they do.

[SYT_Shadow]

when Future Classics took out their F8X front hub conversion for the E9X gen, I pulled the trigger and have continued using the BW Race thread-in studs, no broken ones replacing them yearly. Not that I had many failures before either.

[OG Shark]

Originally Posted by SYT_Shadow

when Future Classics took out their F8X front hub conversion for the E9X gen, I pulled the trigger and have continued using the BW Race thread-in studs, no broken ones replacing them yearly. Not that I had many failures before either.

I've been running those as well and the BW race studs - had good luck with them too. I do have a set of the Core4 waiting to go on the next car though - just wanted to compare the two.

[turbo_joe]

All this talk made me go ahead and order the BW race studs. I have been on the same studs for the last 4 years now so its probably time to replace them

[redpriest]

Originally Posted by tsk94

Unlike rod bearings, it appears the stud 'issue' isn't blown out of proportion. lol

I mean, I've seen 2 E9X M3s blow up on track because of rod bearings and 0 wheels lost on track

[Bartledoo]

Originally Posted by redpriest

I mean, I've seen 2 E9X M3s blow up on track because of rod bearings and 0 wheels lost on track

I've seen zero of each at the track. Both are blown out of proportion

[CorruptCommie]

FEA guy said go MSI over BW Race due to the BW shoulder design causing stress fractures. On my E46M a rear BW Race stud will snap like butter well short of the yearly replacement schedule.

[SYT_Shadow]

Originally Posted by redpriest

I mean, I've seen 2 E9X M3s blow up on track because of rod bearings and 0 wheels lost on track

Originally Posted by Bartledoo

I've seen zero of each at the track. Both are blown out of proportion

I've only seen 1 M3 blow up due to RBs on track, then again I don't track with BMWCCA so I don't see that many M3s. The owner, who had a pristine 2013 M3, also told me he thought it was blown out of proportion right before blowing his engine.

Zero stud related accidents

[DRLane]

I've crewed for a WRL team where fresh BW race studs broke repeatedly over 24 hrs on e36. No other non BMW cars were experiencing this issue. The neighboring clown shoe team was humming along with the Core4 solution.

[tsk94]

Originally Posted by redpriest

I mean, I've seen 2 E9X M3s blow up on track because of rod bearings and 0 wheels lost on track

I've seen the opposite. Many stud failures (across different BMW platforms), 0 rod bearing related motor failures on S65's - but limited sample size.

Regardless, the rod bearing issue is still blown out of proportion. If you factor in the % of cars that actually fail to the number of cars sold, it's a very small percentage. Not saying it shouldn't be done, but people act like it's a time bomb on ALL cars, which is far from the truth in general.

[redpriest]

Originally Posted by tsk94

I've seen the opposite. Many stud failures (across different BMW platforms), 0 rod bearing related motor failures on S65's - but limited sample size.

Regardless, the rod bearing issue is still blown out of proportion. If you factor in the % of cars that actually fail to the number of cars sold, it's a very small percentage. Not saying it shouldn't be done, but people act like it's a time bomb on ALL cars, which is far from the truth in general.

I mean, you're talking to the guy who had a 165k mile car with 60 track days or so before he decided to replace the rod bearings

I've seen stud failures but no wheel falling off in the middle of a turn.

[SYT_Shadow]

Originally Posted by tsk94

I've seen the opposite. Many stud failures (across different BMW platforms), 0 rod bearing related motor failures on S65's - but limited sample size.

Regardless, the rod bearing issue is still blown out of proportion. If you factor in the % of cars that actually fail to the number of cars sold, it's a very small percentage. Not saying it shouldn't be done, but people act like it's a time bomb on ALL cars, which is far from the truth in general.

I think the failure rate of rod bearings is ~1%, maybe less. The item there is the cost vs reward.
The cost of losing an engine is massive. Doing them yourself is ~1500, having a shop do it should be under 3000.

People think the cost of losing an engine is 8k for a new used one, but it is definitely not.
Shops around here charge 5k to remove/replace an engine. So now we're at 8+5.
Then you should factor in doing the rod bearings on that engine, so you're at 8+5+3.
You're also out of a car a good 6 months for the whole event, so you either have a spare car or you'll need to buy one.
You're also going to have to tow your car from wherever it failed to the shop you want to fix it.
So 8+5+3=16k+a car+towing and even then, you'd better hope that used engine you bought off ebay works and doesn't have other issues.

The student I mentioned earlier still didn't have his car up and running 6 months after the event and had to buy a car as that was his DD. I hope saving 1.5k or 3k was worth the epic hassle and 16k he had to pay.


I've seen lots of studs break and have had them break on my own car, but that doesn't translate into 16k of expenses. The vast majority of the time when a stud breaks you find out swapping wheels later in the weekend, not going into a wall.

[tsk94]

Originally Posted by redpriest

I mean, you're talking to the guy who had a 165k mile car with 60 track days or so before he decided to replace the rod bearings

I've seen stud failures but no wheel falling off in the middle of a turn.

That's fair enough.

But what's the difference, really, between one vs. multiple stud failures? It's like comparing 1 spun bearing vs. multiple. Both shouldn't happen, regardless if it's one or many/all.

Worst case scenario, I'd rather my engine blow then my wheel come off at the track. Depending on where it happens, it could very likely be a more expensive incident having the wheel come off than the engine failing and much more potential for injury.

I have friends that have been having stud issues every other track day, and a few people on this forum have been experiencing the same. I'm not hearing of S65's blowing up every other track day due to rod bearing - or if it is happening I'm not hearing about it/seeing it posted anywhere.

The rod bearing problem being blown out of proportional is my opinion, I know some won't agree with me. But, when I say this people seem to think I'm implying you don't need to change your rod bearings. No, that's not at all what I'm saying. I'm a firm believer in preventative maintenance and for the S65 rod bearings are just another maintenance item that needs to be addressed.

[tsk94]

Originally Posted by SYT_Shadow

I think the failure rate of rod bearings is ~1%, maybe less. The item there is the cost vs reward.
The cost of losing an engine is massive. Doing them yourself is ~1500, having a shop do it should be under 3000.

People think the cost of losing an engine is 8k for a new used one, but it is definitely not. Shops around here charge 5k to remove/replace an engine. So now we're at 8+5. Then you should factor in doing the rod bearings on that engine, so you're at 8+5+3.
You're also out of a car a good 6 months for the whole event, so you either have a spare car or you'll need to buy one. You're also going to have to tow your car from wherever it failed to the shop you want to fix it.
So 8+5+3=16k+a car+towing and even then, you'd better hope that used engine you bought off ebay works and doesn't have other issues.

The student I mentioned earlier still didn't have his car up and running 6 months after the event and had to buy a car as that was his DD. I hope saving 1.5k or 3k was worth the epic hassle and 16k he had to pay.


I've seen lots of studs break and have had them break on my own car, but that doesn't translate into 16k of expenses. The vast majority of the time when a stud breaks you find out swapping wheels later in the weekend, not going into a wall.

We've been through this before in the rod bearing thread.

Refer to my previous post, you assume I'm implying not to change rod bearing. I never said that. I'm well aware of the costs associated with a blown motor. They will vary depending on who you get to do the work, but even at the cheap end of the spectrum it's not cheap.

Also, if your wheel comes off due to stud failure, you'd be happy to get away with only a $16k expense if you end up in a wall because of it. You'd be wishing your motor blew instead of some of the examples you see posted on the Core4 site.

[SYT_Shadow]

Originally Posted by tsk94

We've been through this before in the rod bearing thread.

Refer to my previous post, you assume I'm implying not to change rod bearing. I never said that. I'm well aware of the costs associated with a blown motor. They will vary depending on who you get to do the work, but even at the cheap end of the spectrum it's not cheap.

Also, if your wheel comes off due to stud failure, you'd be happy to get away with only a $16k expense if you end up in a wall because of it. You'd be wishing your motor blew instead of some of the examples you see posted on the Core4 site.

I've had multiple engines in my car and am too familiar with the timeline and costs involved, maybe that's why I'm concerned people tend to think rod bearings are insurance against an 8k event

Going into a wall is expensive if you don't have track insurance, and also expensive in terms of risk. Studs shouldn't be breaking all the time, but even when they break they don't result in a wheel coming off.

[redpriest]

Originally Posted by tsk94

We've been through this before in the rod bearing thread.

Refer to my previous post, you assume I'm implying not to change rod bearing. I never said that. I'm well aware of the costs associated with a blown motor. They will vary depending on who you get to do the work, but even at the cheap end of the spectrum it's not cheap.

Also, if your wheel comes off due to stud failure, you'd be happy to get away with only a $16k expense if you end up in a wall because of it. You'd be wishing your motor blew instead of some of the examples you see posted on the Core4 site.

The cost analysis is quite different if you have track insurance - which doesn't cover motor blow up but will cover an incident involving a wheel falling off.

[tsk94]

Originally Posted by SYT_Shadow

I've had multiple engines in my car and am too familiar with the timeline and costs involved, maybe that's why I'm concerned people tend to think rod bearings are insurance against an 8k event

Going into a wall is expensive if you don't have track insurance, and also expensive in terms of risk. Studs shouldn't be breaking all the time, but even when they break they don't result in a wheel coming off.

A lot of the stud related failures are on race cars during races. There's no track insurance available in this situation.

I agree studs shouldn't be breaking all the time, which is why options like Core4, that are proven, are great to have for peace of mind.

When all your studs break on one corner it results in your wheel coming off. Yes this is less likely to happen than just 1 failing, but that clearly doesn't mean it can't happen.

[dparm]

It's hard to generalize about why studs fail -- there's rarely enough data. That's why I don't think there is really a generic solution other than to follow proper procedures with installation, sizing, maintenance, wheel torque, etc. That's all I feel I can do...if they fail despite all of that, then it wasn't my "fault".

[redpriest]

An endurance racing environment is a lot different from an HPDE environment. I'd say the risk of having a stud break when you're changing out wheels on hot rims and studs is a lot riskier than doing 15-20 minute sessions and then cooldown of 1-2 hours between sessions.

I think the core4 hub makes more sense in that situation, and indeed, if you're changing the hubs out anyway, it makes sense too.

[admranger]

I've seen a wheel come off due to studs breaking. Happened to a mod E36M3 driver at turn 8 at willow springs. Car rolled. Later that day my wife was torquing the lug nuts on my race car and said "this one felt funny". I put the torque wrench on it and it broke instantly.

Lucky for me the guy next door had a left handed Matco drill bits and bolt remover kit. I now have one of those as well. Cut through the broken stud like butter.

Does TC Kline still sell stud kits? He had the bullet nosed ones iirc. Seemed like a great set back in the day.

BTW: when I did rod bearings on 3 S-65s in one month, I learned they are a weak link. Mine at less than 30k miles were completely shot. There's pics of them in the rod bearing threads. BEBearings to the rescue.