Centerlock & nurburgring = yikes
Discussion
No idea on how the occupant(s) were. Assume ok. I was just given a link to the video and figured I'd post.
The recall changed the torque spec. Cars were checked for issues from wheels slipping then new nuts fitted which no longer carried a torque spec physically printed on them (presumably so values could be updated in the future without requiring a recall). Nothing was actually changed on the parts iirc.
Of course any part can fail or be fitted improperly but fwiw Porsche don't and have never used this design on any race car with centerlocks.
The recall changed the torque spec. Cars were checked for issues from wheels slipping then new nuts fitted which no longer carried a torque spec physically printed on them (presumably so values could be updated in the future without requiring a recall). Nothing was actually changed on the parts iirc.
Of course any part can fail or be fitted improperly but fwiw Porsche don't and have never used this design on any race car with centerlocks.
fioran0 said:
Of course any part can fail or be fitted improperly but fwiw Porsche don't and have never used this design on any race car with centerlocks.
This is the bit I don't get. I thought they added centre lock to the GT3 for homologation, but fiorano is right - the race cars have a different mechanism. They are more like the Carrera GT mechanism.So are they homologating the wheel carrier on the GT3 and not the locking mechanism&hub? Or is it purely a marketing gimmick (very expensive if it is).
I think I saw about 3 cars loosing a wheel in the 2010/11 track day season alone. Almost all where related to wheels not being fitted properly (incorrect torque and/or safety not engaged properly)- not a hub design issue. However, I believe there was a slight design change early on, with the torque setting being changed also.
noneedtolift said:
I think I saw about 3 cars loosing a wheel in the 2010/11 track day season alone. Almost all where related to wheels not being fitted properly (incorrect torque and/or safety not engaged properly)- not a hub design issue. However, I believe there was a slight design change early on, with the torque setting being changed also.
Do the centrelocks on the road cars have a safety pin fitted like the race cars? If so, failing to correctly seat this, or ensure the wheels are torqued up correctly, leaves the responsibility firmly in the owners camp IMHO.
ked off if that happened to me. Almost enough to put me off a Gen 2 car... Plus I quite fancy something orange 
Centre locks on road cars do not make sense to me. It makes the simple task of changing a tyre or wheel overly complicated when they were designed to allow the complete oposite. Centre locks were devised for fast wheel changes in motorsport, you dont need them on a road car. On the road, they just make everything more complicated and make sourcing cheaper track wheels much more difficult. anyway, centre locks are only half of the solution, you dont see many closed race cars fitted with centre locks without air jacks and they just wouldn't work with cup holders and sat nav imho. There was no need for Porsche to highlight the motorsport connection between a GT3 and a cup car, the perception is that are already reasonably close anyway.
Just like exhaust valves designed to open up and make you feel like Carlos Fandango, they are plain silly.
Just like exhaust valves designed to open up and make you feel like Carlos Fandango, they are plain silly.
fergus said:
Do the centrelocks on the road cars have a safety pin fitted like the race cars? If so, failing to correctly seat this, or ensure the wheels are torqued up correctly, leaves the responsibility firmly in the owners camp IMHO.
No it's a different system - it is more or less a button in the hub. Mechanics and owners alike where new to the system - if you look in the manual swapping wheels is not as straightforward with centrelocks anymore. I think this is where many things went wrong. 400-500NM torque wrench ist also not something you'd bring along to track days when driving the car to the venue... Drive pegs wear as well if you change wheels a lot - not cheap to replace either. Altogether just disadvantages, don't see the point of CLs on road/track day cars personally.
the carrera GT uses a centrelock system similar to the one ferrari use on their challenge race cars, enzo etc IIRC. this has a very large diameter shaft which is threaded on the outside, large nuts are then threaded opposite to direction of rotation so that they should only tighten with use rather than back off (in theory). the Cups, RSRs etc use a smaller diameter centre spindle, again threaded on the outside but the nuts are smaller and just regularly threaded (ie a nut can be used on any corner). these have a safety pin that is inserted after nut is fitted. the cups from 2011 replaced this safety pin with pop out tangs on the spindle, the current RSRs have changed to the larger shaft system same as ferrari and GT making the parts, wheels etc no longer interchangeable. the cup system needs some various other fittings to allow it to work (a locating cup and a pressure disc amongst others) while the ferrari/gt system just uses the wheel and the nut.
the street system is unlike anything ive seen. i assume it was made to make it more user friendly.......
ive heard of another of these fail before on a street car, the shaft itself sheared right off. nut was still attached to the chunk that separated. ive seen photos of a second that failed in the same way.
unclear as to cause though it was debated whether it was just failure or wheel slipping causing the shaft to be stressed and fail. in both cases the hub was pretty well gouged though it couldnt be established whether this was pre or post break. given torque increase recommendation one would assume the latter.
997 RSR hub
996/997 cup hub
the street system is unlike anything ive seen. i assume it was made to make it more user friendly.......
ive heard of another of these fail before on a street car, the shaft itself sheared right off. nut was still attached to the chunk that separated. ive seen photos of a second that failed in the same way.
unclear as to cause though it was debated whether it was just failure or wheel slipping causing the shaft to be stressed and fail. in both cases the hub was pretty well gouged though it couldnt be established whether this was pre or post break. given torque increase recommendation one would assume the latter.
997 RSR hub
996/997 cup hub
Edited by fioran0 on Friday 4th May 13:15
If fitted correctly, there is very little chance of a wheel coming loose with the GT3 centrelocks. The locking 'button' will prevent this. I don't think there's a material safety risk.
However, the benefits of centre lock are very questionable. As said by others, they make finding wheels hard & expensive. Changing tyres harder, swapping wheels at a track harder etc.
However, the benefits of centre lock are very questionable. As said by others, they make finding wheels hard & expensive. Changing tyres harder, swapping wheels at a track harder etc.
apologies for not following this up before now, was travelling.
picture of the failed corner. as you can see, the whole assembly broke off. exact same as ive seen on two others, though this was the cleanest shearing by far.
i assume its incorrect operation/user error. i know for a fact one of the sheared ones ive seen has been this. the intention of posting that video wasnt to scaremonger, i was merely posting out of interest.
that being said, the updated instructions to fit a wheel are now 3 pages long or something. ridiculous!!!!
cup manual its a paragraph and everyone just bangs them on and off with air guns.
picture of the failed corner. as you can see, the whole assembly broke off. exact same as ive seen on two others, though this was the cleanest shearing by far.
i assume its incorrect operation/user error. i know for a fact one of the sheared ones ive seen has been this. the intention of posting that video wasnt to scaremonger, i was merely posting out of interest.
that being said, the updated instructions to fit a wheel are now 3 pages long or something. ridiculous!!!!
cup manual its a paragraph and everyone just bangs them on and off with air guns.
Edited by fioran0 on Saturday 5th May 00:00
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