Torque settings for wheel studs?

[Vader97]

Anyone know the torque settings for wheel studs? Doing a stud conversion and I know the previous lug BOLT setting was 105lbs but what would it be for studs and nuts?

[DentistRodman]

I think it's 25-30 lb ft for studs and 90 lb ft for the nuts when daily driving/100 lb ft when tracking.

[M 4 FUN]

I set my titanium nuts at 130 Nm.

[themightyshrek]

BMW recommends 140 Nm. I bought a "torque wrench" from them that is already set up to this torque.

Product details
Article Number: 71126769683

For all those who want to change the wheels themselves: Tightening the wheel screws too tightly or too loosely can have fatal consequences. The high-quality BMW torque wrench for 17 mm wheel nuts is therefore permanently set to a torque of 140 Nm. This makes the assembly safely reliable.
Benefits of the torque wrench at a glance:

high-quality torque wrench for wheel screws
wrench opening: 17 mm
fixed presetting of the torque to 140 Nm
for the safe installation of the wheels
made of sturdy chrome vanadium steel

[NYG]

M14 bolts are 140 NM.

[MasterP]

Apex M14 Stud Specs: (and likely others)

Torque Wrenches, or wrench with capability to accurately torque to:
■ 24 ft/lbs / 288 in/lbs / 32 Nm.
■ 90 ft/lbs / 122 Nm.

(The wrench should be made by a reputable brand and not abused or out of calibration)

so 100ft. lbs is pretty far past what you should do.

[MasterP]

Originally Posted by M 4 FUN

I set my titanium nuts at 130 Nm.

MRG stated titanium is 90 ft. pounds or roughly 122 Nm. I've broken a set of Ti studs. It's no fun extracting them.

[NYG]

I'll make this easier for you OP, as per U.S. Steel Specifications (AISC/RCSC) (which is way ahead of the rest of the world) and ISO:

The proof load in kN for an M14 bolt with fine threads is 72.5 and 104 (Grade 8.8, 10.9 respectively)

The proof load is the test load at which the bolt begins to exhibit plastic deformation, this is the yield strength of the bolt. Prior to that, the bolt behaves like an elastic spring, it stretches and returns back to its original shape. Because we don't want the bolt elongating (or stretching) much while it's clamping two plies together, we commonly use 3/4 of the proof load as the required clamping force.

Therefore the clamping force for an M14 8.8 and an M14 10.9 bolt is 54.4kN and 78kN respectively.

In order to achieve those clamping forces on a dry zinc plated bolt:

M14x1.25 (Grade 8.8) -> (0.2)*(0.014m)*(54400N) = ~152Nm
M14x1.25 (Grade 10.9) -> (0.2)*(0.014m)*(78000N) = ~218Nm

If lubrication is present, these numbers are even lower.

Conclusion: Use BMW's recommended 140Nm torque spec on the lug nuts.

Source: Structural Engineer

[M 4 FUN]

Originally Posted by MasterP

MRG stated titanium is 90 ft. pounds or roughly 122 Nm. I've broken a set of Ti studs. It's no fun extracting them.

Ok, good, then i'm in the ballpark then .

[MasterP]

Originally Posted by NYG

I'll make this easier for you OP, as per U.S. Steel Specifications (AISC/RCSC) (which is way ahead of the rest of the world) and ISO:

The proof load in kN for an M14 bolt with fine threads is 72.5 and 104 (Grade 8.8, 10.9 respectively)

The proof load is the test load at which the bolt begins to exhibit plastic deformation, this is the yield strength of the bolt. Prior to that, the bolt behaves like an elastic spring, it stretches and returns back to its original shape. Because we don't want the bolt elongating (or stretching) much while it's clamping two plies together, we commonly use 3/4 of the proof load as the required clamping force.

Therefore the clamping force for an M14 8.8 and an M14 10.9 bolt is 54.4kN and 78kN respectively.

In order to achieve those clamping forces on a dry zinc plated bolt:

M14x1.25 (Grade 8.8) -> (0.2)*(0.014m)*(54400N) = ~152Nm
M14x1.25 (Grade 10.9) -> (0.2)*(0.014m)*(78000N) = ~218Nm

If lubrication is present, these numbers are even lower.

Conclusion: Use BMW's recommended 140Nm torque spec on the lug nuts.

Source: Structural Engineer

But he's using a stud conversion. Does this 140nm still apply?

[NYG]

Originally Posted by MasterP

But he's using a stud conversion. Does this 140nm still apply?

If he's using apex stud conversions then he's running grade 10.9 which has a higher clamping force based on bolt strength.

The engineering answer is: Essentially anything lower than the calculated clamping force (75% of the proof load) will keep the bolt elongation at an absolute minimum. In reality, the more slip surfaces you have, the more friction will help and the less bolt force is necessary. So any legitimate manufacturer will typically give you the torque required for their products which will be lower than the clamping torque.

[ValleyBMWs]

Originally Posted by NYG

I'll make this easier for you OP, as per U.S. Steel Specifications (AISC/RCSC) (which is way ahead of the rest of the world) and ISO:

The proof load in kN for an M14 bolt with fine threads is 72.5 and 104 (Grade 8.8, 10.9 respectively)

The proof load is the test load at which the bolt begins to exhibit plastic deformation, this is the yield strength of the bolt. Prior to that, the bolt behaves like an elastic spring, it stretches and returns back to its original shape. Because we don't want the bolt elongating (or stretching) much while it's clamping two plies together, we commonly use 3/4 of the proof load as the required clamping force.

Therefore the clamping force for an M14 8.8 and an M14 10.9 bolt is 54.4kN and 78kN respectively.

In order to achieve those clamping forces on a dry zinc plated bolt:

M14x1.25 (Grade 8.8) -> (0.2)*(0.014m)*(54400N) = ~152Nm
M14x1.25 (Grade 10.9) -> (0.2)*(0.014m)*(78000N) = ~218Nm

If lubrication is present, these numbers are even lower.

Conclusion: Use BMW's recommended 140Nm torque spec on the lug nuts.

Source: Structural Engineer

This is great info - Looking for the same details when using a Titanium stud conversion kit. A few posts mention 15-20 ft lbs titanium studs to hub with blue Loctite and ~90 -100 ft lbs titanium nuts