Edgy01

Of course, even if you loc-tite them you should periodically inspect them to see if the stuff is working. I would pose the question to the suppliers of those offsets. If you're having a problem other people are also having the problem.

Gaspasser19

I have the same size H&R spacers on my 996. I change the wheels twice a year and have yet to notice this problem. I just went out to the garage and checked a few random bolts that I set to 96 ft.lbs. last November. They are still 96. I'm stumped.

springgeyser

Todd- Are you sure your torque wrench is calibrated? I use HR spacer/bolts and do not have this issue.

todd.

I can only judge it by my other cars factory torque settings which it appears to be correct to. However, I guess I could pick up another one just to be safe.

jhbrennan

We are all giving you the obvious "reasons" so you'll have to bear with us - was there any type of lubricant (WD40, grease) on the lug bolts. I've used anti-sieze before and never had any problems but maybe there was some residue on the bolts?? Are you seeing the looseness on the bolts on all 4 wheels?

todd.

The bolts were clean, all four wheels were loose after 200 initial miles.
Yesterday I pulled all bolts, cleaned, applied some blue loctite, drove 100 miles, most bolts were a tad loose. I am beginning to question my torque wrench, so I am reluctantly forking out the money to buy another one today just to rule that out.

Thanks for all the advice, you guys have me working on this, and making me aware of possible issues.

OCBen

Well, I would first borrow someone else's torque wrench to rule out that yours is uncalibrated, unless you plan to return your purchase once you find out yours is okay.

Torque values are typically given for dry, unlubricated threads. That's the only way to reliably predict the required bolt tension for proper preload.

If you're using a thread locking product such as the blue loctite you'll need to crank up your torque values as these products effectively lubricate the threads upon application. I believe there's a correction factor that you can apply for lubricated threads that kicks up the torque by a certain percentage.

Check that. The correction factor is applied in the opposite direction. If threads are lubricated you'll be able to build up more bolt tension with less torque, as the lubrication makes it easier to turn the bolt. So with lubricated threads you should be applying less torque at the bolt head instead of more to achieve the required bolt tension - my mistake.

So that wouldn't explain what's happening in your case.

acadian_dad

According to the owners manual you are supposed to apply some lubricant between the bolt head and the hemisperical "washer" (at least on my 987-S it says this). If this face was not lubricated, I wonder if you are getting the threaded section torqued adequately and then it is working on you ...

OCBen

Excellent point.

I just checked the manual and it says:

Apparently the torque spec specified is for lubricated threads, which means if you don't lubricate the bolts per the manual and then torque the bolts to just 96 ft-lbs, you will be under-torquing the bolts and not building up enough tension in the bolts for proper installation. I think that's what's happening in Todd's case.

Some day it might be practical to own an ultrasonic bolt tension measuring instrument. I used to use one in the lab to precisely set the bolt preload on exploding-nut locking devices used on spacecraft. This instrument measures precisely the amount of bolt tension being applied, irrespective of the torque. You place the magnetic sensor on top of the bolt head and just turn the wrench and watch the readout and stop when the correct tension in pounds is reached. It takes the guesswork out of accounting for friction in the current way of arriving at bolt tension through applied torque, which as we can see can lead to misleading values.


EDIT: Confucius say....

todd.

"Apply a thin coat of Optimoly TA"
You guys ROCK!!!
That's some great advice, and the diagram. It should apply to the H&R bolts too.
I tested a new torque wrench again mine and that's not the problem. While at Sears I picked up the Low Profile 2 1/2 ton jack, which is necessary to get under a 997 S. My 3 Ton required me to remove the plate. With the new low profile I will finally get to use my Corvette jack adaptor which fits perfectly into the slot of the 997 lift point.

jhbrennan

The optimoly is just anti-sieze - I doubt the lack of that is causing your problem. Let us know if there are other developments.

OCBen

Well, if he's been torquing with dry threads then obviously he's been under-torquing the bolts by not using this product which effectively lubricates the threads and reduces the friction. And his problem then is the lack of applying adequate torque on the bolts.

If torque values are given for dry unlubricated threads and your threads happen to be lubricated, then the correction factor is about 0.7, meaning that you should be torquing to only 70% of the specified value if that value is given for dry unlubricated threads.

But now that we know that the specified bolt torque value given by Porsche for these lug bolts is for a lubricated condition, that means that Todd was under-torquing his wheel bolts by as much as 43%, which explains why his lug bolts keep coming loose or losing torque.

Torque wet threads = 0.7 x Torque dry threads

or, as torque values are given by Porsche under wet conditions,

Torque dry threads = 1.43 x Torque wet threads

The actual torque that he should be applying with dry threads is close to 137 ft-lbs, and not the 96 ft-lbs that he's been applying under dry conditions. So he needs to use a similar product if wants to apply the 96 ft-lbs and adequately tension up his bolts.

todd.

And to think I was at 130 MPH on Friday with bolts under torqued by as much as 43%. Scary. I am going to apply the correct aluminum paste and that should take care of the problem.
So I take it that loctite will not be needed?

OCBen

Correctomundo.

Apply the paste in the areas specified by the manual and torque to the specified value.

If it were me, I'd torque them to 100 ft-lbs to be on the safe side, since these bolts are longer than the stock bolts. I'm guessing that the tolerance on the 96 ft-lbs is around +/- 5%. And 100 ft-lbs is just under 5% over. Besides, mechanics typically over-torque them with their air wrenches. I wouldn't be surprised if the techs at the dealer torque them to 130 ft-lbs. You could call them and ask them what they set their air wrenches at. I'm sure it's over 96 ft-lbs.

Verde

Seems to me that you might be running the math in the wrong direction. If you apply a heavy/grease lubricant (which I do NOT believe is the Porsche specified anti-seize) you would have to torque to 137 ft/lbs to get the equivalent of a dry torque setting of 96 ft/lbs. Thus, if anything, he (and many of us) are over-torque'ing the bolts.
However, I don't believe that anti-seize is the same as grease, so the point is moot.
And, if you're out torque wrench shopping, I strongly recommend a split-beam type from Precision Instruments (I have no affiliation with them). The split beam type is more accurate than the typical Sears model and has no 'memory' which means you can leave it set to any torque setting, put it away, and when you take it back out it is not out of calibration. Separately, I've sadly been very disappointed with the lost of quality of Sears tools.
Finally, it sure seems like you're got a problem with your torque wrench. Or so it seems.