Titanium Lug Bolts came loose at the track
05-16-2017, 11:36 PM
#46
Rennlist Member
^Wheel studs/nuts are consumables and I was told to replace at least every two seasons or more depending on frequency of use.
They should also be inspected regularly for corrosion, and I now know (if I ever use them again) to closely inspect the nuts for corrosion or signs that they are not seating properly.
They should also be inspected regularly for corrosion, and I now know (if I ever use them again) to closely inspect the nuts for corrosion or signs that they are not seating properly.
^^^This. If you're tracking, EVERYTHING is consumable. Two seasons for studs and nuts is a good timeline.
Also, for another data point, PCA Chicago (and other PCA regions) restrict nuts and studs to ONLY STEEL for DE tech inspections.
05-22-2017, 08:08 PM
#47
Registered User
News to me... No one has ever asked if my lug nuts were steel... They aren't...
05-22-2017, 08:52 PM
#48
Rennlist Member
05-25-2017, 10:52 PM
#50
Rennlist Member
According to my nominal level of research, the titanium lug bolts are just as strong as the steel OEM bolts, when comparing yield strengths. I have the Motorsports lug bolts on my 911, and I have yet to find that a torque check shows them loose at all. I do like them. However, it is worth noting that the elastic modulus for titanium is about 1/2 that of steel, which means they are twice as "springy". Perhaps this could contribute to loosening somehow during track driving. I have an AX event this weekend and a DE event the following weekend. I will bring my torque wrench set at 96 ft-lbs and check regularly both weekends. If I note any loosening I'll comment back. Interesting topic.
09-01-2017, 04:49 PM
#51
Burning Brakes
Thread Starter
UPDATE:
I have determined the root cause of the problem. It is NOT the titanium bolts (yay!).
Last night I was finally able to return to the track, ran 4 full sessions, checked the torque before each one, and every time every bolt was perfect. Torqued them to 100 ft lbs btw.
Here's what I did to get to this point:
Got my torque wrench calibrated at "Florida Standards Laboratory".
I ran one 20 minute track session a couple of weeks ago, where I checked the torque before/after and I noticed that around half of them where starting to come loose. Problem was that I forgot to bring my recently calibrated torque wrench (duh) so I used a borrowed one at the track, which means that I still couldn't be sure what the real problem was as I couldn't be sure how accurate that wrench was.
A few days later I remembered reading something about lug bolts coming loose due to the bolt seat surface of the wheel being painted. I didn't pay much attention to it when I first read it, but due to being obsessed with the subject at this point, I went out to my car and removed each bolt to check that area. On most of them I found quite a lot of silver paint shavings come off, some other paint baked into the base of the bolts, and on some of them onto the first couple of threads as well.
I took a Dremmel tool with a brass brush tip and scrubbed everything off including the bolts. Keep in mind that I don't have a jack so I had to do one bolt at a time, on the driveway around noon. In August. In Florida. Lovely 2.5 hour job.
After this lengthy procedure, I returned to the track last night - with my torque wrench this time - and every single time I checked all the bolts, none of them moved even a fraction of a turn.
It was the freaking paint. Case closed.
I have determined the root cause of the problem. It is NOT the titanium bolts (yay!).
Last night I was finally able to return to the track, ran 4 full sessions, checked the torque before each one, and every time every bolt was perfect. Torqued them to 100 ft lbs btw.
Here's what I did to get to this point:
Got my torque wrench calibrated at "Florida Standards Laboratory".
I ran one 20 minute track session a couple of weeks ago, where I checked the torque before/after and I noticed that around half of them where starting to come loose. Problem was that I forgot to bring my recently calibrated torque wrench (duh) so I used a borrowed one at the track, which means that I still couldn't be sure what the real problem was as I couldn't be sure how accurate that wrench was.
A few days later I remembered reading something about lug bolts coming loose due to the bolt seat surface of the wheel being painted. I didn't pay much attention to it when I first read it, but due to being obsessed with the subject at this point, I went out to my car and removed each bolt to check that area. On most of them I found quite a lot of silver paint shavings come off, some other paint baked into the base of the bolts, and on some of them onto the first couple of threads as well.
I took a Dremmel tool with a brass brush tip and scrubbed everything off including the bolts. Keep in mind that I don't have a jack so I had to do one bolt at a time, on the driveway around noon. In August. In Florida. Lovely 2.5 hour job.
After this lengthy procedure, I returned to the track last night - with my torque wrench this time - and every single time I checked all the bolts, none of them moved even a fraction of a turn.
It was the freaking paint. Case closed.
09-03-2017, 07:37 PM
#52
Race Director
ATSR...thanks for the update. Hope to see you at Sebring or Homestead sometime.
09-04-2017, 10:25 AM
#53
Burning Brakes
Thread Starter
I ran one session at Homestead a few weeks ago. Looking forward to go back. Fun track!
Haven't run Sebring yet, but it's definitely on the list.
09-04-2017, 10:38 PM
#54
I think in your original post you stated you added NEW WHEELS and Ti studs at the same time. If they loosened on your first track event after adding both you may have experienced the same thing I did. I added both and at may next event both rear loosed to the point I could see them wobble and the front were loose but only noticeable with a wrench. Turns out the paint/powder coat at the mating surface to the hub softened from the heat and allowed the Ti bolts to loosen. I discovered this from slightly disfigured paint on the mating surface. I called the refinishing co. and found they recommended sanding any remaining paint from that area. No problems since.
Check your surfaces and remove any product remaining on either side.
Check your surfaces and remove any product remaining on either side.
09-05-2017, 12:33 AM
#55
Three Wheelin'
Porsche specify to use anti-seize !
They should be applied to the threads as well as between the floating ball and the lug nut. Read your owner's manual, it stated to use Castrol Molub-Alloy paste.
10-02-2017, 04:36 PM
#56
Three Wheelin'
Porsche recommends applying moly lubricants on the lugs and then torque it to 96ft/lbs. The is important because without lubricants, sometimes stictional binding negates any proper torque values. I know, other car manufacturers does not recommend lubricants, but its wise to listen to Porsche in this case.
10-12-2017, 10:02 PM
#58
Drifting
OP this is a non-event.
I have not read any other post but your original.
I check after every session.
Very common thing to happen on ALL Porsche's i have driven. w/ oem lug bolts.
Check them regularly. I have tq wrench in front trunk.
I have not read any other post but your original.
I check after every session.
Very common thing to happen on ALL Porsche's i have driven. w/ oem lug bolts.
Check them regularly. I have tq wrench in front trunk.
10-12-2017, 10:55 PM
#59
Burning Brakes
Thread Starter
It's highly recommended to read thoroughly before posting.
10-14-2017, 11:29 AM
#60
Rennlist Member
Thanks for all your replies!
So it seems that the culprit could be an out of calibration torque wrench from my Indy instead of the rate of expansion of titanium vs steel.
I'm going to have my torque wrench calibrated to make sure it's accurate. By the way, this is the one that I bought:
https://www.amazon.com/dp/B0064FZQR2..._prd_ttl_sol_0
So once I have my torque wrench calibrated and I re-check the torque before each session, I should be ok? Not necessary to use regular steel bolts for the track?
My next track day is in a few weeks.
So it seems that the culprit could be an out of calibration torque wrench from my Indy instead of the rate of expansion of titanium vs steel.
I'm going to have my torque wrench calibrated to make sure it's accurate. By the way, this is the one that I bought:
https://www.amazon.com/dp/B0064FZQR2..._prd_ttl_sol_0
So once I have my torque wrench calibrated and I re-check the torque before each session, I should be ok? Not necessary to use regular steel bolts for the track?
My next track day is in a few weeks.
I bought a more expensive, split beam type torque wrench after developing a distrust for any other type.
