BimmerFest BMW Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
161 Posts
I believe it is 88lbs. It is important not to over torque lug bolts Over tightening puts excess pressure on the rotors and eventually will warp the them. I always make sure I retorque the bolts after I take my car in for tire changes.
 

·
Viv1
Joined
·
211 Posts
I was told its 90 (2008, though)
 

·
Registered
Joined
·
6,805 Posts
And it is dry torque, not wet (as in anti-seize compound on the threads). Do not put anything on the threads of the lugbolts.
 

·
Tar Heel Faithful
Joined
·
14,127 Posts
120Nm like others have said.
 

·
Not a real doctor.
Joined
·
5,702 Posts
Well, whaddaya know! This topic again.

This is a good time for me to own up about something.

Half a year ago, I did a little experiment which, though not conclusive, backed up my assertion and that of anE934fun here, that you should keep the lug nuts dry.

http://www.bimmerfest.com/forums/showthread.php?t=351312&highlight=

Through this, I got to meet and get to know DSXMachina, an experienced mechanic, who pointed out that this is all good in theory, but that without some anti-sieze, the lug bolts can bind up.

I take my wheels on and off every so often when detailing my car. My torque wrench claims to have 700 ft-lbs in reverse. Even so, I had a couple of siezed lug bolts that I could not get off with the torque wrench. Pretty scary.

Bottom line? I now use anti-sieze and I still torque to 88 ft-lbs. Thus, I know I am overtorquing my lug bolts. I torque by hand and am careful, and I'm gambling that I'm not screwing things up badly.
 

·
Registered
Joined
·
6,805 Posts
Well, whaddaya know! This topic again.

This is a good time for me to own up about something.

Half a year ago, I did a little experiment which, though not conclusive, backed up my assertion and that of anE934fun here, that you should keep the lug nuts dry.

http://www.bimmerfest.com/forums/showthread.php?t=351312&highlight=

Through this, I got to meet and get to know DSXMachina, an experienced mechanic, who pointed out that this is all good in theory, but that without some anti-sieze, the lug bolts can bind up.

I take my wheels on and off every so often when detailing my car. My torque wrench claims to have 700 ft-lbs in reverse. Even so, I had a couple of siezed lug bolts that I could not get off with the torque wrench. Pretty scary.

Bottom line? I now use anti-sieze and I still torque to 88 ft-lbs. Thus, I know I am overtorquing my lug bolts. I torque by hand and am careful, and I'm gambling that I'm not screwing things up badly.
How frequently do you remove your wheels? When my E93 went lemon law, I removed the aftermarket wheels and the lug bolts that had been supplied with the wheels and the bolts came out with a simple quick application of an impact wrench. They had been on the car for about a year while my car was getting the 4 failed repair attempts.
 

·
Not a real doctor.
Joined
·
5,702 Posts
Every couple of months. I think I had installed them wet once or twice, and this probably caused the siezing problem.

(Bummer about the lemon.)
 

·
Registered
Joined
·
6,805 Posts
Every couple of months. I think I had installed them wet once or twice, and this probably caused the siezing problem.

(Bummer about the lemon.)
Installing the lug bolts while wet I can easily believe as the cause for the seized bolts. Nothing like galvanic corrosion to cause things to seize up....

As far as the E93 going lemon law, the top/windshield frame A-pillar leaks were not fun. If you check out that same seal on the new Z4s, you can understand why the E93 has leak problems. It would have been nice to not have a leaking top, but at least I was able to get out of that car relatively unscathed (thank you CA Lemon Law).
 

·
Registered
Joined
·
6,805 Posts
Anti-seize doesn't normally cause galvanic corrosion on the lug bolts but the increased tightening tension applied by using a lubricant with the tightening torque spec for a dry fastener, can cause the threads to be over-stressed and seize. Slippery lubes like anti-seize can lower the tightening friction by up to 40% resulting in excessive clamp force on the wheel and hub in addition to over-stressed threads.
I didn't say that anti-seize compound would cause galvanic corrosion. I was responding to the post about installing lug bolts that were still wet from washing causing galvanic corrosion which in turn resulted in a seized up lug bolt.
 

·
Not a real doctor.
Joined
·
5,702 Posts
I didn't use the anti-seize until recently, when I decided to take DSXMachina's advice.

The seized lug bolts may well have seized because the bolt or the hole was not entirely dry before I reinstalled them.

Now that I'm using anti-seize, I am, in fact, overtightening.
 

·
Registered
Joined
·
650 Posts
I have used anti-seize on wheel bolts and nuts for a long time and never had a problem. My theory is that the friction is actually coming from the tapered surfaces of the bolt and wheel rim. When this friction is sufficient the bolts/nuts will not come loose.

A buddy of mine changed from mag wheels to steel wheels for his winter tires. The tapered portion of his wheel nuts was exposed and they began to corrode over the winter. He then installed the summer rims again without noticing the slight rust on the nuts. The next wheel change in the fall was a disaster as the nuts had so much friction that it took a huge 3/4 drive socket set and a special easy-out type socket to finally get them off. In the old days I would have just put a torch to the nuts but with 2 year old mag wheels it didn't seem like a good idea.

This convinced me that the friction between the taper of the nut/bolt head and the wheel is where the torque force is coming from and not from the threads. I keep the taper dry.
 

·
Registered
Joined
·
17 Posts
I have used anti-seize on wheel bolts and nuts for a long time and never had a problem. My theory is that the friction is actually coming from the tapered surfaces of the bolt and wheel rim. When this friction is sufficient the bolts/nuts will not come loose.

A buddy of mine changed from mag wheels to steel wheels for his winter tires. The tapered portion of his wheel nuts was exposed and they began to corrode over the winter. He then installed the summer rims again without noticing the slight rust on the nuts. The next wheel change in the fall was a disaster as the nuts had so much friction that it took a huge 3/4 drive socket set and a special easy-out type socket to finally get them off. In the old days I would have just put a torch to the nuts but with 2 year old mag wheels it didn't seem like a good idea.

This convinced me that the friction between the taper of the nut/bolt head and the wheel is where the torque force is coming from and not from the threads. I keep the taper dry.
Torque spec actually is a component in the formula used to calculate the clamping load produced by the tightened fastener. As you tighten the bolt, you literally stretch / distort it. Threads can only take so much stretch before permanently distorting. Bolt threads will distort and bolts will break if over torqued. There is certainly a friction component where the bolt interfaces with the wheel, and I'm sure BMW has taken that into account in specifying the proper tightening torque.

I found this table interesting. It illustrates the amount of torque needed to produce the desired clamping load with both dry and lubricated fasteners for a variety of bolt sizes and material grades. Torque in the table is presented in lb.-in. Lubricated fasteners seem to require around 75% of the torque needed to achieve the same clamping load as a dry fastener.

http://www.fandisc.com/tti.htm
 
1 - 14 of 14 Posts
Top