Centerlocks - I'm out! ....Hello 5-lug conversion!
02-20-2013, 01:17 PM
#256
Rennlist Member
Agree 101% with Geoff.
Peter (Trakcar) sounds like the 90yo patient of mine who smokes 3 packs of cigarettes daily since teenager and then lectures all my other patients in the waiting room that smoking is not harmful as he is still living. (Peter, I'm sure you can take a joke.)
Peter (Trakcar) sounds like the 90yo patient of mine who smokes 3 packs of cigarettes daily since teenager and then lectures all my other patients in the waiting room that smoking is not harmful as he is still living. (Peter, I'm sure you can take a joke.)
02-20-2013, 01:39 PM
#257
Rennlist Member
I know, I know...
But what is all smokers live to be 90?
No RS that I know of has ever lost a wheel. If you cant find it on the interweb it does not exist.
The GT3's that did fail had a manufacturing defect that is now getting fixed and I have not seen new failures yet. Now, this may change but so far I think drivers are scared of their CL's while they take much more risk driving to the track...
If you dont track a lot, than it is really a non issue.
Why let them spend the money and devaluate (maybe) their cars?
To me the only negative is the grease, but if you are careful you can change wheels without cloves but I wear them anyways and the tools cost you an extra $400.00. Other than that no biggie.
I do agree with Geoff that it is not idiot proof, but you cant fix stupid.
It's pretty simple really.
But what is all smokers live to be 90?
No RS that I know of has ever lost a wheel. If you cant find it on the interweb it does not exist.
The GT3's that did fail had a manufacturing defect that is now getting fixed and I have not seen new failures yet. Now, this may change but so far I think drivers are scared of their CL's while they take much more risk driving to the track...
If you dont track a lot, than it is really a non issue.
Why let them spend the money and devaluate (maybe) their cars?
To me the only negative is the grease, but if you are careful you can change wheels without cloves but I wear them anyways and the tools cost you an extra $400.00. Other than that no biggie.
I do agree with Geoff that it is not idiot proof, but you cant fix stupid.
It's pretty simple really.
02-20-2013, 02:18 PM
#258
Instructor
(which is what I fault porsche for in the design, too complicated and just too different in how you have to think about it...The greased bushing in the nut that is critical to getting the right torque. How many folks deal with this kind of thing on a part that you touch often? The idea that you are locking the system together and any movement indicates you should spend thousands to replace hubs).
That is above stupid that is needing an expert level knowledge for the car to be safely driven on the track.
02-20-2013, 02:40 PM
#259
Rennlist Member
They should have done a better job in explaining it all in the manual, but once you know it should be OK to work with it. It specifies how to warm up your car etc. etc. etc..
The manual saying you have to go to the dealer to change wheels is completely idiotic.
5 lugs dont have that problem, but they have other problems, not saying I prefer one over the other but I personally like CL while understanding why others dont (specially you and about 10 others!) but I dont find it a problem that they are on my car and I am certainly not scared of using them now that the defect has been acknowledged and solved.
The manual saying you have to go to the dealer to change wheels is completely idiotic.
5 lugs dont have that problem, but they have other problems, not saying I prefer one over the other but I personally like CL while understanding why others dont (specially you and about 10 others!) but I dont find it a problem that they are on my car and I am certainly not scared of using them now that the defect has been acknowledged and solved.
02-20-2013, 03:13 PM
#260
CL have hidden failure modes...
Given the pubic information available there is no inspection procedure to determine if the CL need to be replaced (well now one could time out with age). One can torque to spec and have the splines set and still have the hub fail.
This could be due to prior damage (unseen), fatigue (miles), or other causes. Maybe I am missing some conversations but I am not seeing 5 lug wheels fail in anywhere in the same fashion, sure you can forget to torque or leave lugs off but torquing to spec and verifying all the lugs are in place seems like it prevents 99.999% of all 5 lug failures. With CL unless you have access to the internal inspection documents and understand how the CL was maintained one cannot really know if a torqued CL with the splines set is actually safe.
Life is a risk and tracking one's car is a risk, that said we do not track in flip-flops, no helmet, not roll bar, convertibles with 1000hp. There is some expected level of success for all of our mechanical components which figure into our mental equation. If one is not factoring in additional risk for CLs they are fooling themselves. Also for instructors, how can one understand the margin of safety for CL wheels without understanding the history, seeing the car with wheels off and understanding the torque applied?
I guess that is what it boils down to. 5 lugs have a higher margin of safety, CL clearly less (due to complicated procedures, hidden failure modes, limited inspection info and catastrophic failure modes).
I flew for the Navy for 8 years and understand margins of safety in complicated machines/systems. Clearly airplanes would not fly and cars would not race if we required an infinite safety margin so everything is in degrees.
Additional note....
* I will add there is a private (Porsche) inspection document floating around. If you do not have it, find someone who does and understand it. (BTW, I asked a porsche service manager (maybe at mooty's favorite dealer) for any inspection procedures for CLs they told me more than once that they did not exist.) The document adds additional complex inspection criteria to the mix but will give you the best chance of catching a hub problem early (I wish I had it or knew of the content prior to the failure).
The point is one cannot take a quick look at CL hubs and say good enough. There are a bunch of pieces working here but my read is... The wheel absolutely cannot shift on the hub, even a little, any indication of that means loss of torque at some point and the hub should likely be replaced immediately. The nut absolutely has to have proper grease (including the right kind) in the bushing area, this allows proper torquing, without this grease (and slipperiness) in that internal area which transfers force to the wheel you can think you are torquing to spec but you really may or may not be. There are additional pieces like ensure the mating surface have broad contact areas, etc. but one gets the idea.
My 2 cents.
Given the pubic information available there is no inspection procedure to determine if the CL need to be replaced (well now one could time out with age). One can torque to spec and have the splines set and still have the hub fail.
This could be due to prior damage (unseen), fatigue (miles), or other causes. Maybe I am missing some conversations but I am not seeing 5 lug wheels fail in anywhere in the same fashion, sure you can forget to torque or leave lugs off but torquing to spec and verifying all the lugs are in place seems like it prevents 99.999% of all 5 lug failures. With CL unless you have access to the internal inspection documents and understand how the CL was maintained one cannot really know if a torqued CL with the splines set is actually safe.
Life is a risk and tracking one's car is a risk, that said we do not track in flip-flops, no helmet, not roll bar, convertibles with 1000hp. There is some expected level of success for all of our mechanical components which figure into our mental equation. If one is not factoring in additional risk for CLs they are fooling themselves. Also for instructors, how can one understand the margin of safety for CL wheels without understanding the history, seeing the car with wheels off and understanding the torque applied?
I guess that is what it boils down to. 5 lugs have a higher margin of safety, CL clearly less (due to complicated procedures, hidden failure modes, limited inspection info and catastrophic failure modes).
I flew for the Navy for 8 years and understand margins of safety in complicated machines/systems. Clearly airplanes would not fly and cars would not race if we required an infinite safety margin so everything is in degrees.
Additional note....
* I will add there is a private (Porsche) inspection document floating around. If you do not have it, find someone who does and understand it. (BTW, I asked a porsche service manager (maybe at mooty's favorite dealer) for any inspection procedures for CLs they told me more than once that they did not exist.) The document adds additional complex inspection criteria to the mix but will give you the best chance of catching a hub problem early (I wish I had it or knew of the content prior to the failure).
The point is one cannot take a quick look at CL hubs and say good enough. There are a bunch of pieces working here but my read is... The wheel absolutely cannot shift on the hub, even a little, any indication of that means loss of torque at some point and the hub should likely be replaced immediately. The nut absolutely has to have proper grease (including the right kind) in the bushing area, this allows proper torquing, without this grease (and slipperiness) in that internal area which transfers force to the wheel you can think you are torquing to spec but you really may or may not be. There are additional pieces like ensure the mating surface have broad contact areas, etc. but one gets the idea.
My 2 cents.
Is the document you mention the one that was posted somewhere here a few months ago with the side by side photos comparing what it should look like with what it should not look like?
Thanks
02-20-2013, 03:37 PM
#261
If the RS hubs are different than it will apply to all CL's one would think. I would expect all the cars are subject to failure and need the "safer" new hub- not just the 510 cars in this initial recall.
02-20-2013, 04:57 PM
#263
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02-20-2013, 06:29 PM
#264
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02-20-2013, 11:35 PM
#265
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Agree 101% with Geoff.
Peter (Trakcar) sounds like the 90yo patient of mine who smokes 3 packs of cigarettes daily since teenager and then lectures all my other patients in the waiting room that smoking is not harmful as he is still living. (Peter, I'm sure you can take a joke.)
Peter (Trakcar) sounds like the 90yo patient of mine who smokes 3 packs of cigarettes daily since teenager and then lectures all my other patients in the waiting room that smoking is not harmful as he is still living. (Peter, I'm sure you can take a joke.)
02-20-2013, 11:40 PM
#266
Rennlist Member
that fact that there have been any failures in this small of a population of cars points to CL problems. Given that 5-lug systems exist on 100's of millions of car and have few if any failures, and there have been failures in a population of thousands, or in some cases hundreds does not speak well to the CL design or it's tolerance for abuse in the real world.
Just because it hasn't failed yet doesn't make it good.
There should be zero failures in a system of this nature, and it's not like there are not examples of more tolerant systems.
Porsche designed this system for appearance, but as a wheel fastening system, the subsystem's primary purpose, it should not be subject to nuance or incorrect/customer applications.
Porsche's stated faith in the system (legally motivated or otherwise) is basically an admission of a substandard system for which everyone should be concerned, those driving the cars and those sharing the track with a wheel that is subject to fly off based on the competence of our fellow hobbyist.
The system is crap, quit defending it, expert systems with low application tolerances are not what is needed in the real world and it's existence endangers the driver of the vehicle and all the cars and drivers at the same track. Since any wheel leaving the vehicle at a high rate of speed becomes a projectile capable of untold damage to it's surroundings.
100+ years into the automotive industry we should not have to worry about this sort of failure. There is no advantage to the system and there are documented disadvantages, I don't see why anyone considers this system something worth defending.
The system has many Con's, please list the Pro's for me and then tell me that very very short list of Pro's is worth the hassle.
And BTW IMHO this has screwed the resale value for any seller of these cars in the future - since a knowledgable buyer will have to consider the replacement cost. So saying this bad design has no effect on you is simply ignoring that fact that this system will be understood and absorbed by the markets for the full life cycle of these cars.
It's a high cost, complex, low reliability and novel system that should've never been brought to market. And we're all paying for it one way or another.
my $0.02
Just because it hasn't failed yet doesn't make it good.
There should be zero failures in a system of this nature, and it's not like there are not examples of more tolerant systems.
Porsche designed this system for appearance, but as a wheel fastening system, the subsystem's primary purpose, it should not be subject to nuance or incorrect/customer applications.
Porsche's stated faith in the system (legally motivated or otherwise) is basically an admission of a substandard system for which everyone should be concerned, those driving the cars and those sharing the track with a wheel that is subject to fly off based on the competence of our fellow hobbyist.
The system is crap, quit defending it, expert systems with low application tolerances are not what is needed in the real world and it's existence endangers the driver of the vehicle and all the cars and drivers at the same track. Since any wheel leaving the vehicle at a high rate of speed becomes a projectile capable of untold damage to it's surroundings.
100+ years into the automotive industry we should not have to worry about this sort of failure. There is no advantage to the system and there are documented disadvantages, I don't see why anyone considers this system something worth defending.
The system has many Con's, please list the Pro's for me and then tell me that very very short list of Pro's is worth the hassle.
And BTW IMHO this has screwed the resale value for any seller of these cars in the future - since a knowledgable buyer will have to consider the replacement cost. So saying this bad design has no effect on you is simply ignoring that fact that this system will be understood and absorbed by the markets for the full life cycle of these cars.
It's a high cost, complex, low reliability and novel system that should've never been brought to market. And we're all paying for it one way or another.
my $0.02
02-21-2013, 01:52 AM
#267
Rennlist Member
Thread Starter
.....now tell us how you really feel! 
Good on ya Dave, I can't dispute any of this, unfortunately CL's on the 991 GT3's confirms that Porsche thinks otherwise. What now?
Good on ya Dave, I can't dispute any of this, unfortunately CL's on the 991 GT3's confirms that Porsche thinks otherwise. What now?
02-21-2013, 02:05 AM
#268
Rennlist Member
^Porsche responded with a 4200 track mile CL maintenance ie pass the buck to the owner. Wonder if that has opened in Porsche lore with all the 5 lugs with this maintenance schedule - air cooled and on- my bet never!!! Mike.
02-21-2013, 03:01 AM
#269
GT3 player par excellence
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02-21-2013, 03:24 AM
#270
GT3 player par excellence
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Last edited by mooty; 02-22-2013 at 02:27 AM.