Titanium Lug Bolts revisited
10-31-2019, 06:27 PM
#1
Rennlist Member
Thread Starter
Titanium Lug Bolts revisited
I'm not re-hashing the old thread regarding whether or not to get some as they may or may not loosen. I have them on my 2009 C4S and have loved them until I recently had a brake flush done and the Indy workshop
servicing my car brought it to my attention that the 40mm bolts attaching the rear wheels which are mounted with 15mm spacers are only making 6-7.5 mm of thread contact and they felt that was insufficient and UNSAFE. I purchased a set of 20 of the Porsche Titanium lug bolts 2/20/2017 for my 2009 911 C4S. At the time I bought the stock length , not realizing my rear wheels had 15 mm spacers. When they were delivered it didn't take long to realize I had ordered the wrong product. After I contacted the vendor , we worked out an exchange for the 40mm lug bolts which are advertised as IDEAL FOR CARS USING 10-15mm WHEEL SPACERS . Installed the 40mm on my Champion wheels and thought no more about it based on my trust in the phrase "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS ". Yesterday I contacted the vendor because the facility working on my car pointed out to me that the 40 mm bolts on the rear wheels with 15mm spacers were making insufficient thread depth contact and as such were UNSAFE due to only 6 to 7.5 mm of thread contact (4 or 5 threads). The vendor and I had a discussion regarding whether this was UNSAFE or not. Based on our discussion I was left with the impression that he felt 7.5 mm of contact was not UNSAFE with 96-100 ft lbs of torque but also mentioned that wheel adaptors were available.
Subsequently I learned that 14mm of thread contact is what most industry people consider SAFE. So I'm asking the vendor to reconsider describing the 40mm lug bolts as "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS" as they may be putting other customers into an UNSAFE situation. I have subsequently ordered Porsche 50mm lug bolts to swap out for the UNSAFE (for cars with 15mm spacers) 40mm lug bolts purchased from the vendor . So now I have ten 40mm titanium lug bolts FS. PM me if interested
servicing my car brought it to my attention that the 40mm bolts attaching the rear wheels which are mounted with 15mm spacers are only making 6-7.5 mm of thread contact and they felt that was insufficient and UNSAFE. I purchased a set of 20 of the Porsche Titanium lug bolts 2/20/2017 for my 2009 911 C4S. At the time I bought the stock length , not realizing my rear wheels had 15 mm spacers. When they were delivered it didn't take long to realize I had ordered the wrong product. After I contacted the vendor , we worked out an exchange for the 40mm lug bolts which are advertised as IDEAL FOR CARS USING 10-15mm WHEEL SPACERS . Installed the 40mm on my Champion wheels and thought no more about it based on my trust in the phrase "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS ". Yesterday I contacted the vendor because the facility working on my car pointed out to me that the 40 mm bolts on the rear wheels with 15mm spacers were making insufficient thread depth contact and as such were UNSAFE due to only 6 to 7.5 mm of thread contact (4 or 5 threads). The vendor and I had a discussion regarding whether this was UNSAFE or not. Based on our discussion I was left with the impression that he felt 7.5 mm of contact was not UNSAFE with 96-100 ft lbs of torque but also mentioned that wheel adaptors were available.
Subsequently I learned that 14mm of thread contact is what most industry people consider SAFE. So I'm asking the vendor to reconsider describing the 40mm lug bolts as "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS" as they may be putting other customers into an UNSAFE situation. I have subsequently ordered Porsche 50mm lug bolts to swap out for the UNSAFE (for cars with 15mm spacers) 40mm lug bolts purchased from the vendor . So now I have ten 40mm titanium lug bolts FS. PM me if interested
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JPSimpson (11-03-2019)
10-31-2019, 07:50 PM
#2
Rennlist Member
I'm not re-hashing the old thread regarding whether or not to get some as they may or may not loosen. I have them on my 2009 C4S and have loved them until I recently had a brake flush done and the Indy workshop
servicing my car brought it to my attention that the 40mm bolts attaching the rear wheels which are mounted with 15mm spacers are only making 6-7.5 mm of thread contact and they felt that was insufficient and UNSAFE. I purchased a set of 20 of the Porsche Titanium lug bolts 2/20/2017 for my 2009 911 C4S. At the time I bought the stock length , not realizing my rear wheels had 15 mm spacers. When they were delivered it didn't take long to realize I had ordered the wrong product. After I contacted the vendor , we worked out an exchange for the 40mm lug bolts which are advertised as IDEAL FOR CARS USING 10-15mm WHEEL SPACERS . Installed the 40mm on my Champion wheels and thought no more about it based on my trust in the phrase "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS ". Yesterday I contacted the vendor because the facility working on my car pointed out to me that the 40 mm bolts on the rear wheels with 15mm spacers were making insufficient thread depth contact and as such were UNSAFE due to only 6 to 7.5 mm of thread contact (4 or 5 threads). The vendor and I had a discussion regarding whether this was UNSAFE or not. Based on our discussion I was left with the impression that he felt 7.5 mm of contact was not UNSAFE with 96-100 ft lbs of torque but also mentioned that wheel adaptors were available.
Subsequently I learned that 14mm of thread contact is what most industry people consider SAFE. So I'm asking the vendor to reconsider describing the 40mm lug bolts as "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS" as they may be putting other customers into an UNSAFE situation. I have subsequently ordered Porsche 50mm lug bolts to swap out for the UNSAFE (for cars with 15mm spacers) 40mm lug bolts purchased from the vendor . So now I have ten 40mm titanium lug bolts FS. PM me if interested
servicing my car brought it to my attention that the 40mm bolts attaching the rear wheels which are mounted with 15mm spacers are only making 6-7.5 mm of thread contact and they felt that was insufficient and UNSAFE. I purchased a set of 20 of the Porsche Titanium lug bolts 2/20/2017 for my 2009 911 C4S. At the time I bought the stock length , not realizing my rear wheels had 15 mm spacers. When they were delivered it didn't take long to realize I had ordered the wrong product. After I contacted the vendor , we worked out an exchange for the 40mm lug bolts which are advertised as IDEAL FOR CARS USING 10-15mm WHEEL SPACERS . Installed the 40mm on my Champion wheels and thought no more about it based on my trust in the phrase "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS ". Yesterday I contacted the vendor because the facility working on my car pointed out to me that the 40 mm bolts on the rear wheels with 15mm spacers were making insufficient thread depth contact and as such were UNSAFE due to only 6 to 7.5 mm of thread contact (4 or 5 threads). The vendor and I had a discussion regarding whether this was UNSAFE or not. Based on our discussion I was left with the impression that he felt 7.5 mm of contact was not UNSAFE with 96-100 ft lbs of torque but also mentioned that wheel adaptors were available.
Subsequently I learned that 14mm of thread contact is what most industry people consider SAFE. So I'm asking the vendor to reconsider describing the 40mm lug bolts as "IDEAL FOR CARS USING 10-15mm WHEEL SPACERS" as they may be putting other customers into an UNSAFE situation. I have subsequently ordered Porsche 50mm lug bolts to swap out for the UNSAFE (for cars with 15mm spacers) 40mm lug bolts purchased from the vendor . So now I have ten 40mm titanium lug bolts FS. PM me if interested
10-31-2019, 08:04 PM
#3
Rennlist Member
Thread Starter
This is what we're talking about in terms of thread contact. Does this look safe to you?
You are correct, 1.5mm per turn, 5 turns equals 7.5 mm, 7-8 turns equals 14mm contact. They could only get 5 turns max .
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10-31-2019, 09:43 PM
#6
Racer
The lug bolts are M14's. A quick rule of thumb is that you should have 1.5 x the diameter for thread engagement, or 2.0 x diameter to be really safe.
So 14 x 1.5 = 21 mm.
If what you're trying to show in that photo is that those bottoms threads are the only ones with evidence of contact ... then you've barely got 5mm. Even less if you figure that first thread has a chamfered lead.
So 14 x 1.5 = 21 mm.
If what you're trying to show in that photo is that those bottoms threads are the only ones with evidence of contact ... then you've barely got 5mm. Even less if you figure that first thread has a chamfered lead.
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JPSimpson (11-03-2019)
10-31-2019, 10:07 PM
#7
Rennlist Member
Thread Starter
Yes on some bolts they couldn't even get five full turns so they weren't in even 7.5mm. My point is 40mm bolts should not be touted as " IDEAL FOR CARS WITH 10-15mm SPACERS". Likely OK for cars with 10mm spacers but definitely NOT OK for 15mm spacers.
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10-31-2019, 10:20 PM
#8
Rennlist Member
Great catch by your mechanic. When I asked my dealer mechanic to install my newly procured Ti bolts while they were installing new tires on my Cayenne, they said too short, not enough turns to get proper depth. Fortunately I was able to swap them out for just the cost of postage.
11-01-2019, 09:43 AM
#9
RL Community Team
Rennlist Member
Rennlist Member
I've heard you want 9 threads. Yours were definitely too short to be used with spacers. On my Cayenne I run a DRM style spacer where the spacer mounts to the hub and the wheel mounts to the spacer (they're thixh at 25mm). I bought 2 different lengths of Ti lug bolts and used the ones that go all the way to the end of the spacer threads without contacting the rotor hub surface, wh ih means I'm somewhere between 3/4"-7/8" thread engagement length, but on a 650 HP vehicle that weighs 5,000 lbs and has 315 width contact patches at all 4 corners its generating a lot of load to those attachment points which is one of the reasons I went Ti in the first place.
Glad your mechanic found this before it became a real issue (wheel coming off)!
Glad your mechanic found this before it became a real issue (wheel coming off)!
11-01-2019, 05:14 PM
#10
Rennlist Member
Thread Starter
Yes, had spacers on the front as well so now have 20 slightly used 40mm Ti lug bolts FS, So PM me anybody who wants them at a reduced price. They retailed for $275 + $16 shipping . Make me an offer, they're beautiful but unusable by me.
11-02-2019, 01:09 PM
#11
Rennlist Member
I have ACER black titanium lug bolts on my 2010 c4s, which had standard 29mm length threads.
Therefore,
For 10mm spacers: ACER sells lug bolt thread length of 39mm
For 15mm spacers: ACER sells lug bolt thread length of 44mm
Therefore,
For 10mm spacers: ACER sells lug bolt thread length of 39mm
For 15mm spacers: ACER sells lug bolt thread length of 44mm
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ThunderRolls (11-02-2019)
11-02-2019, 06:04 PM
#12
Rennlist Member
Thread Starter
Well you might want to check yours because my Ti 40mm bolts with 15 mm spacers only gave me 6-7.5 mm of thread depth/contact
Last edited by Bomar Shelby; 11-02-2019 at 06:29 PM.
11-02-2019, 06:26 PM
#13
Rennlist Member
Bomar,
Your post states that you were incorrectly using 40mm length lug bolts with your 15mm rear spacers (not 44mm, which is what I believe you should be using).
Your post states that you were incorrectly using 40mm length lug bolts with your 15mm rear spacers (not 44mm, which is what I believe you should be using).
11-02-2019, 07:36 PM
#15
Rennlist Member
No worries and great that you made the change (agree that 40mm threads for 15mm spacers are too short and unsafe).
Last edited by Greg2010; 11-03-2019 at 06:15 PM.