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05-18-2020, 04:01 PM | #23 |
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I'm curious for people that have experienced stud issues/failure on the E9X M3 using the 12mm studs. Are you guys not running hub centric wheels or non-hubcentric spacers? I don't quite understand how so much stress could be put on the studs if you were running hub centric wheels and/or spacers. If you are indeed not running hub centric, then I understand how the failures can occur.
My experience with this platform is quite limited, I come from E36 land. But on my previous car, a E36 M3 race car, I never experienced stud issues. In fact, in ~10 years of racing the car and multiple lapping days a season on top of racing, I never once had a stud fail, OR even need to be replaced. I was always running hub centric wheels though. And it's not like this car was cruising around on a leisurely laps, it was driven hard - it won regional championships 5 times and held lap records. So I'm curious to hear what some of you have to say. Are you those that experienced stud failures running hub centric wheel/spacer setups? Does this chassis, somehow, stress the studs that much more??? |
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05-18-2020, 05:09 PM | #24 | |
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05-18-2020, 05:20 PM | #25 | |
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My understanding is that on a hub centric wheel, the load or force is transferred onto/through the hub since it's perfectly contacting the wheel bore. On a non hub centric wheel, since the hub and centre bore of the wheel aren't making contact the studs bare all the load and stress. Maybe I'm wrong, but from what I've read this is my understanding. Hearing of all these people complaining of failures and upgrading to 14mm studs has me a bit paranoid, but also confused. |
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05-18-2020, 05:30 PM | #26 | |
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I'm telling ya----there's just something about our platform once you get enough power, grip, aero, braking and reduce the lap times........something is up. Let me tell you this story: My friend and I have the same car---E90 M3. Same suspension. Same wheel widths---10.5" square. Same tires---Pirelli DH 305. Same rear wing. Very similar front aero. Both cars supercharged. We used to have the same AP brakes until I moved to Essex AP. Same brake pads. These two cars are very similar. The biggest difference is that my car is gutted and caged and his is not.....just a light stripping. He uses different studs and nuts than me. He uses a different torque wrench than me. And we use different alignment shops with slightly different settings. In early 2019, we were at the same track event at Chuckwalla. During that event, we both broke studs on the same corner of the car---front driver side. Chuckwalla has a banked bowl that is particularly punishing to the front driver side. I mean.....c'mon....we both broke studs on the same corner of the cars at the same event...... And for me, over 90% of the stud breaks are exactly the same----they break inside the hub, which is exactly what kind of break he had. And my stud breaks have occurred with different brands of studs. And they've broken regardless of whether it was me installing them or a shop. Pleeeeeeeease don't tell me it's just simple clamping force and that we're doing something wrong. I'm not a race team mercilessly gunning nuts on and off while everything is molten hot in an endurance race......Something is up. Since I put the 14mm threaded studs in the front, I've had zero problems. I'm really looking forward to the 14mm press-ins now.
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05-18-2020, 05:36 PM | #27 | |
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Something I'll have to look into more. Don't want to deal with stud failures - doesn't sound like fun. |
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05-18-2020, 05:53 PM | #28 | |
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I love your build that you put together. I highly recommend either the Core4 press-ins in 14mm or the Future Classic threaded 14mm hubs. It's cheap insurance. There's literally NO downside to running 14mm studs. I've been running 14mm on the front for a year (via drilled out hubs with the Rogue Engineering jig kit). You just torque them down to a higher ft lbs than 12mm. Ok, so your arms get a little more workout...... (I promise, I do not gain anything by making these recommendations. I have no ownership stake, don't get any commissions or free stuff from any of this. I'm just a guy who is god damn tired of breaking studs and begged Core4 to make a 14mm solution for me. Now that he did the homework and produced them, everyone else can buy them too.)
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05-18-2020, 06:34 PM | #29 |
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We've been reading broken stud stories for as long as there have been stud conversions for multiple manufacturers, not just BMW.
Not trolling, genuinely curious - has anyone seen a broken OEM bolt from track use? I don't see how the benefits could possibly outweigh the drawbacks to using thread-in studs nor why the various suppliers keep selling them. |
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05-18-2020, 07:12 PM | #30 | |
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Other then on the E9X chassis, the studs have been pretty bullet-proof on the BMW chassis from my experience - assuming you aren't treating them poorly. Zero issues with them on both a E30 and E36 race car personally. |
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05-18-2020, 08:45 PM | #31 |
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Thanks everyone this is all great info. I tracked / club raced an e36 m3 from 1999 to 2008 and probably had over 50 track days on one set of studs. I think I changed the nuts a few times.
The whole thing with the e92 and breaking studs makes me nervous and kind of leaning towards staying with the oe bolts for now. If I do studs I’ll likely go for the MSIs but I only plan to do a few auto x and track days a year so it’ll likely be fine? I ordered the snap on collet style remover today for $20 and they even already shipped it. I’ll see how it works next weekend, I won’t get to it this coming weekend. |
05-19-2020, 11:57 AM | #32 |
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Hey all,
I've covered the wheel stud topic ad nauseam in different threads in here so I'll try to be as succinct as possible (impossible....I type more than talk as dogbone can attest LOL). The "lightness" of E36 and E46 cars seems logical relative to the E9x M, but these chassis' breaking studs in the series I run in (AER) is what prompted me to even bother offering a press-in stud converted BMW hub. And, we aren't even allowed to run anything beyond 180tw "street" tires. The majority of failures happening on the rear corners (think cycling brake AND engine torque) and more than 50% of them without wheel spacers. I was growing tired of hearing about, and more importantly, worried for my fellow racers that experienced breaking studs after a pretty serious wreck (driver's ok) from losing a wheel in a very high speed section at Mid-Ohio (E36). Ironically enough, this same driver had the same exact thing happen in the same spot on the same track in a different car with a different team a year later (E90 328). You can see the incident as well as others on my website here (just about every stud brand is pictured in here, including almighty MSI and even a couple M14's): https://www.core4motorsports.com/gal...mw-wheel-studs Does session duration play a role? I'd say likely. Most guys tracking/racing are only pushing the car on track for 20-45 minutes at a time where they can check stud torque between sessions. AER/WRL/endurance events have 20-24 hours of total track time in a single weekend with the car on track for many hours at a time. BUT, there have even been cases of brand new studs installed for the weekend that broke within a few hours on the first day of racing. Also, most don't check wheel stud torque during pit stops because internet lure has led us to believe that checking torque when "hot" is somehow more detrimental than the risk of having insufficient preload/clamping. And if you talk to anyone who's in the field of nut/bolt/fastening, insufficient preload is the single largest proponent to cause fastener failure; especially the failure mode that wheel studs fail (bending fatigue). It is far more difficult than many think to truly overload a high strength M12 fastener with a cone/ball seat nut in an aluminum wheel by torquing them. In fact, you won't even get a permanent set/deformation in a grade 10.9 M12 stud using a cone seat nut if you torque them to 150 ft-lbs. And if a screw-in stud does break while torquing it or removing it from the hub, count your blessings because it was compromised in previous use and luckily didn't let go on you in the middle of turn. Are wheel bolts actually more robust than screw-in studs? The answer is yes. This is specifically due to the very nature of how screw-in studs need to be manufactured in order for them to bottom out to prevent screwing in any further. Thread run-out regions, or in other words areas where threads start/end are stress concentrations. One of these areas of a screw-in stud just happens to always sit perfectly at a point of peak [bending] stress and where they break. You can clearly see that in the "broken stud gallery" I shared above. dogbone mentions the F8x uses M14, but ironcially enough the GT4 car is supplied by BMW with "stepped" studs that are M14x1.25 that thread into the hub and M12x1.5 portion that you tighten the lug nut onto. BMW GT4 stud: BMW is basically saying that the clamping capacity of a M12 stud is sufficient for racing use at that level. The main difference here vs a M12 screw-in stud is having the larger M14 part in the hub provides a large increase in strength/material and resistance to bending fatigue failure (the GT4 stud has a couple of other features I won't bore you with). An M12 press-in stud offers the same/similar effective diameter as an M14 thread where it is installed into the hub because threads have "roots" where the diameter necks down. An M14 thread root diameter is actually slightly smaller than the diameter of the M12 press-in studs we use where it presses into the hub. The M14 press-in stud we use is larger than both by a huge margin where it installs into the hub. So, with the extra clamping capacity of a M14 studs, combined with huge increase in material size in a peak [bending] stress area, it will take a significant lapse in preparation and judgment or material defect to break one. M14 press-in on right, M12 press-in on left:
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05-19-2020, 04:16 PM | #33 | |
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I have Apex wheel studs with the hex key in the ends. I haven't needed to use the installer, but I tried it today and it works on my studs. The installer has three pieces: the housing, a ball bearing and the hex bit screw in the end. In order to get it to work I have to remove the ball bearing. Apex recommends 24 ft-lbs, which is not much. The nosing on the Apex hex cap studs is about 1/2" long. I agree with you that the 3/4" nosing of your bullnose studs are probably too long for it. Here are two videos of how the second collet stud remover works. A video shows it better than I could describe. Start at 1:40 for the first video. Collets work based on the principle of pressure, squeezing the stud.....not grabbing the threads. Definitely not as fast as I remembered, but anything can be quick with repetition. https://www.youtube.com/watch?v=sU8m0eX4cEw https://www.youtube.com/watch?v=4IFF...ature=youtu.be If anyone is interested the snap-on kit number in the second video is CGM515B. The tool part numbers for the minimum number of pieces for M12x1.5 are CG500-49, CG325-6 and CG513-1. I would call them to confirm if there is anything else; they are always very helpful on the phone. |
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05-19-2020, 05:06 PM | #34 |
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This is a misunderstanding. You don't need to remove the parking brake to run the Core4 rear hubs. If you want to change out a stud with the hammer out/pull-in technique, you will need to remove the parking brake shoes/mechanism to gain clearance. There are no clearance issues with the stud heads and the parking brake mechanism in place.
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05-19-2020, 05:43 PM | #35 | |
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05-27-2020, 03:06 AM | #36 | ||
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05-27-2020, 01:30 PM | #37 |
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This has been my experience. Of a few different wheels I've used on the E92, none remain properly hub centric with a 5mm spacer, and most 7mm spacers. 3mm usually leaves enough of a lip, but 5mm & 7mm do not. Until you get to a 10mm spacer where the hub centric portion is then part of the spacer itself. For this reason I've never ran 5mm or 7mm spacers as the wheel (in almost all cases) is no longer hub centric.
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05-27-2020, 02:02 PM | #38 |
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All of my breaks, except for the last two at Chickwalla, were with either no spacer or a 3mm spacer. Believe me, I asked this question many many times. I even switched from flow formed wheels to forged wheels to see if that would stop the breakages. It didn’t.
The best story I can tell you on this topic comes from Strom motorsports who is a super high end race car builder. Brett Strom told me a story where they built two identical E92 race cars. One broke studs all the time and the other never broke studs. Ultimately, he was just resigned to switching out the studs on a very regular basis. |
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05-30-2020, 08:04 PM | #39 |
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So I failed on my attempt today to remove the studs. I got 8 of 20 out. I used the snap on collet tool but it’s totally marred and unusable now. I was using a impact to tighten and loosen. They definitely used red loctite. I spent about 2 and half hours to get that far with a lot of swearing mixed in.
I tried the standard double nut method even with a impact to tighten and it wouldn’t budge. Should I use some heat? If so where exactly on the stud and for how long? I’m nervous using the tool that mangles the threads so that if it goes bad I’m ina worse place now with a stuck broken stud. Any words of advice or wisdom? |
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05-30-2020, 09:40 PM | #40 | |
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The Amazon tool is $20 and can be delivered Monday via Amazon Prime. Seriously......at this point what have you to lose by trying it? If you get the Amazon tool and have any questions, you can PM me.
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05-30-2020, 10:43 PM | #41 |
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Dog one, Have you tried it with red loctite? I swear I have to really crank on them for it to move and I am no weakling. I wonder if I throw some heat on it? Do I heat at where the stud goes in and for how long?
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05-30-2020, 11:37 PM | #42 | |
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Yes I used to use red loctite in the past, but then I realized blue was enough. The tool pulled red loctite studs fine too. I don’t use heat on a healthy stud. Didn’t see the need. I guess it's worth mentioning that you should have a decent impact gun. And if your impact gun is a 1/2" drive, you need a reducer to 3/8" for the Amazon tool. As far as heating loctite----when I would be removing a broken nub out of a hub, I would use a propane torch and heat the area for a couple minutes at least. And you should have the brake rotor off so you can heat the hub face as well as the base of the stud. It's very hard to heat a hub face if the rotor is on. Other things I used to do: -chase the threads with a thread chaser and WD-40 to remove the old loctite and clean the threads. Used this set: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 -brakekleen everything -I would run Q-tip swabs with alcohol to make sure the threads were free of any leftover residue. -double-nutted the new studs on carefully all to the same torque with blue loctite. -if it was a maintenance replacement at home, after installing the new studs, I would leave the car in the air overnight without putting the wheels on to let the loctite set. Yeah......all that and I still broke 12mm threaded studs on a quasi-regular basis. I am very much looking forward to running the press-in studs.
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05-31-2020, 08:18 AM | #44 |
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