For racing and track customers, Rogue Engineering is proud to offer our MOTORSPORT wheel studs. We wanted to not only produce a stud with unique features for the BMW enthusiast but one of the strongest ones on the market.
"2.9. Wheel studs are required. Studs must be made of at least 190,000 psi steel and be long enough that threads extend beyond the torqued nut."
AER competitors! Are the studs you're using up to spec?
Grade 12.9 hardware does not meet the requirements.
Hardware certified by ISO/TS 16949 and ISO 9001 by TUV does not meet requirements.
Although our studs are tested beyond these specifications, it does not mean that they're designed to last a lifetime! Like other items on your racecar, make sure you time out your equipment!
How To Make A Better Stud
After seeing many people break studs over the years, we were determined to look at the science of "why" this was happening. With input of many drivers, customers, racers, and dealers, we continued to develop the best (and safest) stud possible.
When vehicles start breaking studs, a lot of questions arise such as:
- How old are the studs?
- What material are the studs made from?
- When were they changed?
- How many track hours (if a track driven car) do the studs have?
- Are you using wheel spacers?
- What torque are you using for the nuts?
- When were you torquing them (hot or cold)?
- Are you using a torque wrench (when was it calibrated)?
- What wheels are being used?
Choosing the Material
Regular laboratory testing of the material alone (nothing to do with stud design) has shown that our MOTORSPORT studs exceeded Grade 12.9 yield strength by an average of 14.6% and tensile strength by 10.6%. What does all these numbers mean? This means one of the strongest studs money can buy. For reference, a factory BMW wheel bolt is a Grade 10.9 in strength.
Rogue Engineering stud strength vs. other grades of studs
Details in the Design
Material choice alone does not define the stud. As we started looking at obvious data, we then started looking at the design of specific studs and potential issues. Mechanical issues to address were a top priority.
Based on where the studs were breaking (near the hub face), it did not make sense why studs made from high quality material were sheering. After looking more carefully, there was an issue when impacting lug nuts onto studs, as they would actually drive the stud down into the hub MORE, because there was no defined "shoulder" to stop the stud from moving. The hub was actually cutting into the portion of the unthreaded stud, weakening the stud near the hub.
The Rogue Engineering Motorsport stud has an very pronounced and defined shoulder (red arrow) for the stud to bank up to and terminate on the hub face. This defined and enlarged shoulder ensures that the stud does not move when the wheel nuts are being driven on and torqued in place.
Another engineered specification on the new MOTORSPORT stud is a clearly defined undercut behind the shoulder (blue arrow). This very minute detail ensures that the stud's shoulder will absolutely bottom out on the hub face during the installation. Granted a small detail, but preventing the stud from moving after install is important to its strength.
Another detail is the unthreaded area (green arrow) portion of the stud. In actuality, this portion of the stud resides under the brake rotor hat and wheel pad, so no threads are actually required in this area. Not having threads reduces the risk of failure because of stress risers from unnecessary threads.
Rogue Engineering MOTORSPORT Studs Technical Specifications
- Machined from a unique Chromoly Alloy Steel, hardened and tempered to beyond Grade 12.9 class to DIN/ISO 898 (independent lab testing shows much higher strength)
- Max Torque Recommendation: Recommended torque on BMW applications maximum is 90 ft. lbs. (M12 size) or 105 ft. lbs. (M14 size) COLD torque. DO NOT HOT TORQUE WHEELS!
- New! Trivalent Chromium Black Zinc coating much more resistant to rust over previous finishes
- Roll forged thread construction means a stronger thread than studs that are simply machined.
- Bullet nose design allows for easier wheel installations
- Studs are available as M12 and M14 (1.5mm thread pitch) configurations. F-Series compatible studs coming soon.
How much torque is too much torque?
A common question we get is how often should studs last? Perhaps a better answer is the actual inspection of the stud itself. Although a stud may appear "fine", closer inspection may show otherwise.
Below is a picture of a new stud and a yielded stud with a thread pitch gauge, showing that a stud has clearly been over stretched beyond its yield point. It would be a matter of time before this yielded stud would break while being used.
Stud Service Life
When is the time to replace studs? Unfortunately, most decide to do it when it is too late, when they've already broken one or more studs. We have surveyed and asked many racers and drivers and it would be the consensus that approximately 10 hours of track use would be a safe interval for a stud change. Driving to the track event does not count as "interval time". If you attend the average HPDE, generally speaking, a driver will get 1.5 hours of track time. With this in mind, the studs should be changed after 7 track events. This also means NO nut torquing while in the "hot pits" as the actual temperature of the stud can increase by 30%. This is generally for M12 stud users. Our experience with M14 studs is much longer!
Fits the following vehicles:
- M12 x 1.5 will fit E36, E46, E39, E60, E63, E9X, E82, E88, E85, E89
- M14 x 1.5 will fit E53, E65 (and 3-series cars with our hub conversion kit)
We do not yet have the M14 x 1.25 size to fit OEM F8X M2/M3/M4 vehicles.
Installation Notes: We recommend the use of Loctite 262 on the base of the threads of the stud during installation. Installation of the studs into the hub only requires 15 ft. lbs. We find the "double-nut" method to be the best way to install these.