Centerlock Wheel System and Track Usage
08-31-2011, 01:16 PM
#1
Drifting
Thread Starter
Centerlock Wheel System and Track Usage
There are some things trackrats need to be aware of and fully educated on in regards to using OE centerlock system on track.
The CL system has proven its durability and strength both in the recent Pikes Peak Hillclimb on a GT2RS and in the 24 hours Nurburgring race on an GT3RS last year. Both of these cars were fitted with the OE centerlock system (not a Cup or Carerra GT style centerlock system which is totally different from GT2/GT3 system!).
When basic procedures are followed and routine examination is done, the CL system should be expected to be safe and troublefree. Here are some tips:
A scarred/damaged hub resulting from too low torque/loose centerlock nut will be immediately obvious upon visual examination. It would appear as deep concentric gouges in the metal. In this case the hub must be replaced. In a correctly maintained CL system, hub damage like this would not occur.
A wide, greyish, non-gouged coloration pattern, in the area that the inner part of the nut rides on the hub, is normal.
It should be considered that there is no advantage in torquing more than 600Nm, even 550 is is ok if the nut's torque is checked after evey track day.
While it is true that the centerlock system compared to a five lug is not much weight difference, the CL arrangement does allow for a lighter wheel: less mass necessary in the center. The CL hub itself is heavier but the wheel can be/is lighter.
The CL system has proven its durability and strength both in the recent Pikes Peak Hillclimb on a GT2RS and in the 24 hours Nurburgring race on an GT3RS last year. Both of these cars were fitted with the OE centerlock system (not a Cup or Carerra GT style centerlock system which is totally different from GT2/GT3 system!).
When basic procedures are followed and routine examination is done, the CL system should be expected to be safe and troublefree. Here are some tips:
- Preload the system following the Porsche recommended procedure! You have to grease, because without grease you use up a lot of torque overcoming the friction between the CL ring and the wheelcone.
- The recommendation from 500nm to 600nm is solely adding an additional safety margin to the system to ensure enough preload pressing the wheel to the hub flange.
- If slicks are used on the car the load on the hub system is up to 20-30% higher than with standard tires. In that case 600 Nm preload torque is important because static g forces in cornering are up to 1.7 g's instead of 1.4 on Michelin Pilot Sport Cups
- Checking the hubs is important- the system can be torqued up to more than 1000 Nm before any of the components gets irreversible damage.
Crucial is to see if the hub has a lot of marks (caused by movement of the wheel against the hub) sometime in its life. - Cup car hubs "time-out" at 100 hrs. That goes for 5 bolt hubs as well. When on track 80% driving in your GT3 does no harm, 100% driving requires race-car type maintenance.
- Bottomline- the system is safe as long as you treat it right. But even then, after thousands of hard track miles you should consider renewing some parts, even though its not pointed out part by part in the manual. If you use your car as a racecar you should perform regular inspection/replacement the same way.
- Regarding the hubs: If they look ok, drive on. There is no reason to believe that anything will break without first showing marring/gouging signs on the horizontal part of the hub.
A scarred/damaged hub resulting from too low torque/loose centerlock nut will be immediately obvious upon visual examination. It would appear as deep concentric gouges in the metal. In this case the hub must be replaced. In a correctly maintained CL system, hub damage like this would not occur.
A wide, greyish, non-gouged coloration pattern, in the area that the inner part of the nut rides on the hub, is normal.
It should be considered that there is no advantage in torquing more than 600Nm, even 550 is is ok if the nut's torque is checked after evey track day.
While it is true that the centerlock system compared to a five lug is not much weight difference, the CL arrangement does allow for a lighter wheel: less mass necessary in the center. The CL hub itself is heavier but the wheel can be/is lighter.
Last edited by savyboy; 09-01-2011 at 11:59 AM. Reason: Add a bit of info
08-31-2011, 01:28 PM
#2
Rennlist Member
Savy: Any chance this came from a conversation with a "friend" or is this just based on your experiences so far? Thank you so much for this post regardless.
08-31-2011, 01:36 PM
#3
Rennlist Member
Thanks Savy, excatly what I was thinking.
Makes sense.
Track use is different then street use, driving near 100% makes it worse, driving on slicks even worse.
Savy got lot's of friends; It happens when you buy "one each" LOL
Makes sense.
Track use is different then street use, driving near 100% makes it worse, driving on slicks even worse.
Savy got lot's of friends; It happens when you buy "one each" LOL
08-31-2011, 01:40 PM
#4
Rennlist Member
I was thinking of one particular bonnet-signing friend 
08-31-2011, 01:48 PM
#5
Burning Brakes
Hi Pete,
This is great info for the guys with centerlocks!
It is my opinion that you should be the new writer for the next GT car's owners manuals, or aleast the "Trackrat Supplement".
Your notes above are exactly the type of info that should be included. Imagine having some additional useful technical info, along with the usual garden variety stuff (ok someone else can write that part!).
CL's can be torqued to 1000Nm before damage, .....good to know and gives additional confidence to all owners.
Cheers!
Doug N.
This is great info for the guys with centerlocks!
It is my opinion that you should be the new writer for the next GT car's owners manuals, or aleast the "Trackrat Supplement".
Your notes above are exactly the type of info that should be included. Imagine having some additional useful technical info, along with the usual garden variety stuff (ok someone else can write that part!).
CL's can be torqued to 1000Nm before damage, .....good to know and gives additional confidence to all owners.
Cheers!
Doug N.
08-31-2011, 01:55 PM
#6
Rennlist Member
Quote:
ChrisF: I was thinking of one particular bonnet-signing friend
Quote:
Savyboy: If the CL mechanism times out with track use WE NEED TO KNOW ABOUT IT PORSCHE
Quote:
TRAKCAR: Don't you speak to AP every other weekend? He's be a good guy to ask the question, or point out this link of potential metal fatigue nonsense.
ChrisF: I was thinking of one particular bonnet-signing friend
Quote:
Savyboy: If the CL mechanism times out with track use WE NEED TO KNOW ABOUT IT PORSCHE
Quote:
TRAKCAR: Don't you speak to AP every other weekend? He's be a good guy to ask the question, or point out this link of potential metal fatigue nonsense.
08-31-2011, 01:55 PM
#7
Admin
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The one that said that the CLs are lighter? Great..
Anyway, Savy is right; CLs and 5l wheels and hubs are "constantly check for wear items" in the race cars.
Why would it be any different for the "street" versions.
The question is (and always will be) WHY do it in the first place.
A not proven CL system in a street car.. Come on!
Anyway, Savy is right; CLs and 5l wheels and hubs are "constantly check for wear items" in the race cars.
Why would it be any different for the "street" versions.
The question is (and always will be) WHY do it in the first place.
A not proven CL system in a street car.. Come on!
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08-31-2011, 01:57 PM
#8
Rennlist Member
CL's can be torqued to 1000Nm before damage, .....good to know and gives additional confidence to all owners.
I'm pretty sure I put a couple of 1000Nm on one of them when I broke it. But it was a front one and they don't do much anyway.
08-31-2011, 02:29 PM
#9
Instructor
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How about a section in the Savvyboy addendum on tools needed?
1) 500 ft lb torque wrench
2) 40 inch breaker bar
3) 3 feet of thick wall pipe
4) Paint can opener from Lowes.
5) Medical truss for the hernia caused by trying to use the breaker bar without the pipe extension.
6) Patient second person to stand on the brakes.
7) Beer.
1) 500 ft lb torque wrench
2) 40 inch breaker bar
3) 3 feet of thick wall pipe
4) Paint can opener from Lowes.
5) Medical truss for the hernia caused by trying to use the breaker bar without the pipe extension.
6) Patient second person to stand on the brakes.
7) Beer.
08-31-2011, 02:33 PM
#10
Rennlist Member
How about a section in the Savvyboy addendum on tools needed?
1) 500 ft lb torque wrench
2) 40 inch breaker bar
3) 3 feet of thick wall pipe
4) Paint can opener from Lowes.
5) Medical truss for the hernia caused by trying to use the breaker bar without the pipe extension.
6) Patient second person to stand on the brakes.
7) Beer.
1) 500 ft lb torque wrench
2) 40 inch breaker bar
3) 3 feet of thick wall pipe
4) Paint can opener from Lowes.
5) Medical truss for the hernia caused by trying to use the breaker bar without the pipe extension.
6) Patient second person to stand on the brakes.
7) Beer.
2) 40 inch breaker bar ==> Use #1.
3) 3 feet of thick wall pipe ==> Use #1.
4) Paint can opener from Lowes.
5) Medical truss for the hernia caused by trying to use the breaker bar without the pipe extension. ==> Eat more cheese.
6) Patient second person to stand on the brakes. ==>Truck pedal depressor
7) Beer. ==> Lots and lots of beer and Vodka.
08-31-2011, 02:34 PM
#11
Race Director
Admin's...this should be a sticky for a while.
Savy, thanks for the info...wherever you got it and even though I don't know you I believe you have real true info and I thank you for that.
Plus I think of guys like you, Trakcar and Izzone...2 guys I do know and see how they deal with CL's with many many miles of fast track use with out and issues. I'm like them and very detailed and follow things like this by the book and then double check.
Thanks for the peace of mind!
Savy, thanks for the info...wherever you got it and even though I don't know you I believe you have real true info and I thank you for that.
Plus I think of guys like you, Trakcar and Izzone...2 guys I do know and see how they deal with CL's with many many miles of fast track use with out and issues. I'm like them and very detailed and follow things like this by the book and then double check.
Thanks for the peace of mind!
08-31-2011, 02:43 PM
#12
Instructor
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TRACKAR of you can get my wheels off after a DE with my 40 inch torque wrench and just muscle power (or your body weight) them the beer, vodka and cheese are on me.
08-31-2011, 02:46 PM
#13
Race Director