DJN

Let's step back to CL's for a moment Randy. Now do you think that the "drive pins" or "dummy lugs" as I call them are actually strong enough to drive or brake the car on their own? What else is helping them, or actually taking on most of the force?

Izzone

I think it is a secondary safety, they have a purpose and there is a reason on a 997.2 Turbo there are centerlock specific rear rotors and non centerlock specific rear rotors......and yes the centerlock sepcific fits exact on a 997.2 GT3.

If installing a rotor with a hole larger than the stud was OK why did Porsche go through the hassle of machining two seperate pieces for teh same vintage car?

Non centerlock
99735240502 / 99735240602

Centerlock
99735240503/ 99735240603

DJN

Fair enough (one beer for you!).....but I think this is for positioning and Porsche knows there is MUCH force on the back of a 911 so best to over engineer. Torquing the CL bolt holds everything in place firmly. What is one piece of evidence that occurs when a CL bolt becomes slightly loose? One or more drive pins loosen because they can't take the drive or braking force.


Doug N

911rox

Not sure Randy but as I'd previously mentioned, i was accidently shipped the 997.1 pccb hats with my front rotors and the holes on those were exactly 1mm larger... Considering the hats are screwed to the hub, maybe they transfer the braking force?? Being so close to the centre of rotation, the torque experienced by those screws would be far less at a guess...???

Izzone

I don't even install those screws

They serve no purpose

ECS Tuning

I spent some time researching this more in depth yesterday, and realized the need for four separate center lock conversion kits, as each uses slightly different components.

All kits have 20 brand new lug bolts included.

First, for GT3 models. All GT3 use the same rotor design, whether they were equipped with center lock hubs or not. This makes the conversion slightly easier, and gives you a great opportunity to inspect for excessive brake component wear. Either kit is compatible with PCCB equipment.

GT3 owners can use the early design 2008 and earlier hubs (as the original poster DJN has done).

This kit can be found HERE (Current Price: $1685.95)

All 997 Turbo models with steel brake rotors have a different design to the rotor dependent upon whether the car was optioned with Center Lock or 5 lug hubs. This increases the cost of the kit, as the correct rotors are included. However, if you are to the point where you need to replace your rotors anyhow, it's a good opportunity to make the switch.

Steel rotor 997 Turbo kits can be found HERE (Current Price: $2509.95)

997 Turbo and GTS models that originally came with PCCB equipped, however, will not necessitate a change in rotors, as the PCCB rotor is the same, regardless of hub design.

This kit is HERE (Current Price: $1655.95)

The final of the four kits is for 997 GTS models originally equipped with steel brake rotors. This situation is similar to the 997 Turbo, in that a brake rotor change is necessary when converting to 5 lug hubs.

More information on this kit can be found HERE (Current Price: $2349.95)

DJN

Hi ECSTUNING,

Thank you so much for your post! Nicely put together.

One question I have for Option #2....you state "GT3 owners can also choose to use the later 2010 and up hubs. These are the hubs Porsche installed on 997.2 GT3 and RS". My question is how can you use the "hubs Porsche installed on 997.2 GT3 and RS" when they are actually part of the original 997.2 GT3 and RS CL hardware?

Something is not quite right here. Perhaps there is now a new Part# for the older gen 997.1 GT3 and RS hubs?

Anyway, see photo below..... the "hubs" are the largest pieces in the photo (obviously, CL left, 5 lug right).

Cheers!
Doug N

ChrisF

DJN: I searched but did not find specific wheel sizes and offsets to be used with the conversion. There was mention of using 5 lug GT3 wheels with a rear 5mm spacer. Would you mind elaborating of updating post #1?

Thanks again for all your trailblazing in this conversion process.

ECS Tuning

It was a mis-representation of the PET system. My apologies, it has been amended.

DJN

Hi ChrisF,

You are most welcome!

Wheel and tire sizes, theoretical offsets for the CL to 5 lug conversion are precisely the same for 997.1 GT3/RS and 997.2 GT3/RS.

Note that the Gen 1 cars use a 5mm spacer in the rear, so the wheel offset on a narrow body for example, is actually 68mm, but stepped out to 63mm when combined with the spacer. If you are ordering new wheels just use the standard Gen2 narrow or widebody offsets as a guide. Offsets do not change as a result of the conversion.

For my narrow body conversion I used:

Forgeline GA3R wheels: 8.5x19et 51mm (-2mm from OEM) and 12x19et63mm (same as OEM).

Cheers!
Doug N

DJN

Whew! Thought I was losing my mind........

rja

I'm very seriously considering converting from CL -> 5-lug because CL means …

- Fragile installation / maintenance procedure with potentially catastrophic consequences of getting it wrong (and hence, safety concerns)

- Ironically, more time spent changing wheels w/ a single nut than 5 w/ nuts.

- More tooling to lug to DE events

- Fewer wheel options

- Overall, a PITA

Thank you Doug for your write-up! If just for the cost of parts, I’d not hesitate to pull the trigger. But @ 4/hrs per corner that’ll double the cost. Perhaps a shop can do it in significantly less time? I have plenty of experience building cars (big projects, ground -up, etc.) so DIY is an option, but haven’t taken on this particular job and have little experience working on Porsche. At 4/hrs per corner, this is clearly an involved job so I’m not inclined to rush into it blindly. Any pointers to add’l info available?

Thanks,

-Roland.

P.S. FWIW, your car looks great Doug. The CL is to blingy for my tastes and I like the more sensible look of the 5-lug. Not a decision factor for me but icing on the cake should I convert.

DJN

Roland,

You can save some $$ by R&R the wheel carriers yourself like I did. Then take the wheel carriers to the dealer or independent shop to do the wheel bearing and hub pressing. Note you will need an alignment afterwards, but you wanted to have a nice track set up done anyway (right? ).


Cheers!
Doug N

Nacelle

Wow.....

What a thread!

Thanks to Doug and all who have made such valuable information available.

I just recently picked up a 997.2 GT3 and was looking to replace my silver wheels with black wheels still using the CL system. After reading all of this it sure makes me wonder... back to doing more homework.

rja

Thanks Doug. Good advice. Any 3.8 RS owners out there who have gone this route? Any wheel recommendations? I like the factory or BBS motorsport look.