Quote:
Originally Posted by ryanosiecki
Where did you end up on weight?
I have heard of this breakage issue, but I am getting mixed messages on why this actually happening. Some say it’s the user over torquing or torquing while the hub is still hot, etc. Then on the flip side I have heard of defective product. Is there any evidence on this?
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My car now with the carbon doors (70 lbs loss from fully gutted doors) and carbon headlight blanks (15 lbs loss---NOT 40 LIKE BIMMERWORLD CLAIMS!!!!) should be hovering right at 3100lbs no fuel no driver. Every scale is different. But I think it's possible that we're a couple pounds under 3100lbs.
As far as studs, I'm not blaming defective product. And if you know anything about my build thread, I have been on a quest for knowledge over the last 8 years. That learning didn't blindly ignore the topic of studs. In fact quite the opposite. As I kept breaking studs, I kept doing more research, trying different brands of studs, trying different types of steel, trying to use careful technique on installation, trying not to abuse them with an impact gun when they're hot (I don't do long wheel to wheel races), replacing them right at 12 months, trying forged wheels versus flow formed, calling high end race shops to see if they had any advice. Believe me, I have not just played the victim on this topic. I found no 100% reliable solution while on 12mm studs.
Strom Motorsports is a very high end race car builder. He puts like $200k into every car he builds. I spoke to him one day and he said that they built two identical E92 M3 race cars with 12mm studs. One never broke studs. The other broke them regularly. He was resigned to the idea that they just need to replace them every 6 months.
I believe that this platform---for whatever reason---puts odd stresses on the studs on the front wheels. And once you have enough power and grip, the problem starts to surface. My friend has an E90 M3 setup very similar to me---supercharged, JRZ, AP Racing, full aero, etc. He never broke a stud. Then he moved up to Pirelli DH 305 square. Almost immediately, he broke a stud at Chuckwalla. Chuckwalla has a banked bowl turn that puts enormous stress on the front of the car. I broke two studs there that same weekend. And our broken studs were on the same corner of the car. I mean, c'mon.......this my fault?
I'm sorry, but anyone who simply tells you that studs are only taking a simple clamping force and aren't dealing with any other kind of load, and that everyone breaking studs is doing something wrong, are not looking at the whole picture. Something else is coming into play.
I used the Rogue Engineering jig kit to drill out E9X M3 front hubs to 14mm. That's been doing really well so far for almost a year. (I didn't drill the rears to 14mm because I'm concerned the rear flanges don't have enough margin to be drilled out, so the rears are 12mm.) I don't like having to change the torque value on my CDI torque wrench for front and rear, so ultimately, I will figure something out that has the same settings all the way around the car. I love the press in stud idea, but on the E9x M3, it's looking like the rear press in studs can't be swapped out while the hub is on the car if you have a parking brake (which I do). So, you may have to remove the rear hub flange to replace the press in studs which is a huuuuuuge pain in the ass. I haven't sorted it out my final ideal solution yet.