** Spacers Accredited **

[valcax]

I want to know the spacers thickness accredited for Boxster MY99.

I know 5mm is accredited cause I have seen these spacers in tequipment kit, but 17mm (for rear) is written in Owners Manual MY00.

Do you know with accurate which spacers are accredited for a boxster MY99? (front and rear)

wheels:

front: 225/40 ZR18 7,5/50

rear: 265/35 ZR18 9/52

Best regards.

[Loren]

You will find approved spacers as well as wheels and tires in TSB 2/04 4440 Summer Tire and Wheel Summary -- dated May 25, 2004. As a Contributing member you can read that in the TSb section here.

[valcax]

You will find approved spacers as well as wheels and tires in TSB 2/04 4440 Summer Tire and Wheel Summary -- dated May 25, 2004. As a Contributing member you can read that in the TSb section here.

Thanks Loren, Can you tell me thickness approved? I have not clear.

[Loren]

5 mm front and rear

or

5 mm front and 17 mm rear (with specified tire and wheel sizes).

[valcax]

5 mm front and rear

or

5 mm front and 17 mm rear (with specified tire and wheel sizes).

Well, In mycase 5mm f/r only approved, but I have question about bolts.

I understand there is no necessary to replace standard bolts for longer bolts as footnote 5 is not marked. What can you tell me?

[Loren]

The 5mm spacers require a longer wheel bolt. The 17mm spacers have bolts to the rotor/hub and then you use your original bolts to bolt the wheels to the 17mm spacers.

[valcax]

The 5mm spacers require a longer wheel bolt. The 17mm spacers have bolts to the rotor/hub and then you use your original bolts to bolt the wheels to the 17mm spacers.

Hi loren, pay attention to TSB, footnote 5 (only with connection with longer bolts..) IS NOT MARKED for

225/40/18 7,5 /50

265/35/18 9/52

only 2 (for boxster from MY98) and 3 (remove spacers when mounting spare wheel) ARE MARKED.

I am convinced longer bolt is not required for this wheel size.

[Loren]

Yes, but elsewhere in that TSB you will find:

Wheel mounting must take place with the 5 mm longer wheel bolts of the 911 GT3, Part No. 996 361 203 90 or 996361 98000. These GT3 wheel bolts are marked with GT or with a red color on the face surface (arrow) of the bolt head, or the rotating spherical cap ring is galvanized in red. Dimension X = approx. 50 mm. Tightening torque: 130 Nm (96 ftlb.).

If you use 5 mm spacer (with any wheel or tire) your existing bolts will be 5 mm too shorter. This means that there will be 5 mm less thread contact to hold the wheel on.

Porsche sells the 5 mm spacers with the longer (5 mm longer) bolts. I would not use the 5 mm spacers without the 5 mm longer bolts.

[valcax]

Yes, but elsewhere in that TSB you will find:

Wheel mounting must take place with the 5 mm longer wheel bolts of the 911 GT3, Part No. 996 361 203 90 or 996361 98000. These GT3 wheel bolts are marked with GT or with a red color on the face surface (arrow) of the bolt head, or the rotating spherical cap ring is galvanized in red. Dimension X = approx. 50 mm. Tightening torque: 130 Nm (96 ftlb.).

If you use 5 mm spacer (with any wheel or tire) your existing bolts will be 5 mm too shorter. This means that there will be 5 mm less thread contact to hold the wheel on.

Porsche sells the 5 mm spacers with the longer (5 mm longer) bolts. I would not use the 5 mm spacers without the 5 mm longer bolts.

That TSB part is for size wheels that require longer bolts.

Note that correct contact to hold the wheel depends on deep throat and offset, what I mean is standard bolts can be approved to hold wheels with 5mm spacers in 225/40/18-265/35/18 but not with another.

So I understand.

Could you contrast to Porsche?

[Q-Ship986]

I looked at these TSB's:

-- 4/04 4440, dated May 25, 2004, Summer Tire and Wheel Summary

-- 5/04 4440, dated Sep 14, 2004, Winter Tire, Wheel, & Snow Chain Applications

On page 7 of both TSB's, it is pretty clear: When using the 5mm spacers (no matter what wheel), you must use the +5mm GT3 bolts.

However, there is a discrepancy in the footnoting, which is apparently fouling the situation here. Note the following:

-- The summer tire TSB does not denote use of the +5mm bolt when outlining use of the spacer for the 18" wheels at the bottom of page 2 (see footnotes on page 3).

-- The winter tire TSB does denote use of the +5mm bolt for the same wheels on page 3.

Considering page 7 of both TSB's, coupled with practical logic, use +5mm bolts with 5mm spacers.

--Brian

[valcax]

I looked at these TSB's:

-- 4/04 4440, dated May 25, 2004, Summer Tire and Wheel Summary

-- 5/04 4440, dated Sep 14, 2004, Winter Tire, Wheel, & Snow Chain Applications

On page 7 of both TSB's, it is pretty clear: When using the 5mm spacers (no matter what wheel), you must use the +5mm GT3 bolts.

However, there is a discrepancy in the footnoting, which is apparently fouling the situation here. Note the following:

-- The summer tire TSB does not denote use of the +5mm bolt when outlining use of the spacer for the 18" wheels at the bottom of page 2 (see footnotes on page 3).

-- The winter tire TSB does denote use of the +5mm bolt for the same wheels on page 3.

Considering page 7 of both TSB's, coupled with practical logic, use +5mm bolts with 5mm spacers.

--Brian

good job!! However I still think there is no mistake in TSBs, page 7 of both TSB is for size wheels that require longer bolts.

In 18" winter tires, longer bolts are required and not in summer tires. I am not sure if I am thinking wrong but this is what TSB says!

[Q-Ship986]

good job!! However I still think there is no mistake in TSBs, page 7 of both TSB is for size wheels that require longer bolts.

That is not how I read page 7 in either TSB. These pages state:

"Wheel mounting must be done using the 5 mm longer wheel bolts of the 911 GT3..." (5/04 4440)

and

"Wheel mounting must take place with the 5 mm longer wheel bolts of the 911 GT3..." (4/04 4440)

It doesn't say anything like "for size wheels that require longer bolts."

In 18" winter tires, longer bolts are required and not in summer tires. I am not sure if I am thinking wrong but this is what TSB says!

It doesn't make any sense for the wheel bolts to be different between summer/winter tire use on the same wheels. However, it is perfectly understandable to me that when technical documents are written for technical matters that are among many hundreds of thousands of pages of technical documents, that sometimes an error or omission is made. I think that is the case with the footnoting for that wheel on page 2 of TSB 4/04 4440.

This is a car company that shaved fractions of millimeters from their lug bolts to save unsprung weight. If they are recommending a longer bolt in this instance, they mean it.

--Brian

[valcax]

Do you really think Porsche publish TSB with no exhaustive checking? I really dont believe.

What you say is sense but TSB says it.

However, as we are in whole doubt, I have bought the complete kit with longer bolts. No concern money, only I am seeking for curiosity and learning.

[valcax]

Do you really think Porsche publish TSB with no exhaustive checking? I really dont believe.

What you say is sense but TSB says it.

However, as we are in whole doubt, I have bought the complete kit with longer bolts. No concern money, only I am seeking for curiosity and learning.

Today I have been mounting spacers. Impossible for me unscrew little screws on hub. I have installed spacers with no screw, but with 130Nm on longer bolts. I just hope no problem. What do you think?

[Q-Ship986]

Today I have been mounting spacers. Impossible for me unscrew little screws on hub. I have installed spacers with no screw, but with 130Nm on longer bolts. I just hope no problem. What do you think?

The little screws are more for convenience...they hold the spacer to the rotor/hub. They keep the spacer in place when mounting the wheel and when removing the wheel. If you don't use the screws, then the spacer may stick to the back of the wheel or simply fall. If the spacer falls into the wheel, it could scratch or otherwise damage it. The lug bolts hold the wheel, spacer, and rotor firmly to the hub. --Brian

Edited September 24, 2006 by Q-Ship986

[valcax]

Today I have been mounting spacers. Impossible for me unscrew little screws on hub. I have installed spacers with no screw, but with 130Nm on longer bolts. I just hope no problem. What do you think?

The little screws are more for convenience...they hold the spacer to the rotor/hub. They keep the spacer in place when mounting the wheel and when removing the wheel. If you don't use the screws, then the spacer may stick to the back of the wheel or simply fall. If the spacer falls into the wheel, it could scratch or otherwise damage it. The lug bolts hold the wheel, spacer, and rotor firmly to the hub. --Brian

Then I can do without screw with no problem (unless removing a wheel).... thanks Qship, now I am in calm.

[valcax]

in Spanish forums, many customers have installed 7mm spacer front and 15mm rear (with longer bolts), as they are sold by FVD, but this is not approved by Porsche!! They say all is ok!! CAN I INSTALL???

[w_pienaar]

This has been a subject that also interests me. Is it possible to have some before and after photographs.

Cheers

Edited February 18, 2007 by w_pienaar

[986Jim]

I have used 5mm spacers on lots of cars (VW Mostly to push the wheels out the Euro-look) and have never put extended wheel studs on to make up for them and have never had a problem. The wheel nuts have a lot of threads to hold them on and losing 5mm is not enough to cause a problem, espicaly on a 5 lug car. Hell we did 10mm spacers on 4 lug golf's with the stock studs and no problems never mind 5mm.... (for years too from the MK2 85-91 Golf's forward to now)

I have a feeling Porsche tells us that more for a liability standpoint than anything else. If in the off chance something were to ever happen, then everybody who bought spacers would get free studs from porsche with installiation which would cost a mint.

[mikefocke]

I'm always amazed that so many people

think they know more than the OEM engineers.

My bet is Porsche engineers taking into consideration the way many of its cars are driven (Auto-X, track, twisties, tail of dragon, etc). If you were to ignore Porsche's warning to install longer bolts and only use the car for tooling around town showing off your new wheels, you'd be fine. But stress the things over a long track day and you could be in trouble. Or put a super stress on them in an emergency situation and you could be in trouble. Porsche engineers to prevent that, is my guess.

Think of the longer bolts as a way of getting new shiny bolts that help show off those new wheels and be safe. Or take your chances with advice that contradicts that of the OEM. Your choice.

Edited February 25, 2007 by mikefocke

[986Jim]

I'm always amazed that so many people

think they know more than the OEM engineers.

My bet is Porsche engineers taking into consideration the way many of its cars are driven (Auto-X, track, twisties, tail of dragon, etc). If you were to ignore Porsche's warning to install longer bolts and only use the car for tooling around town showing off your new wheels, you'd be fine. But stress the things over a long track day and you could be in trouble. Or put a super stress on them in an emergency situation and you could be in trouble. Porsche engineers to prevent that, is my guess.

Think of the longer bolts as a way of getting new shiny bolts that help show off those new wheels and be safe. Or take your chances with advice that contradicts that of the OEM. Your choice.

Well it's a good thing that I own a Race shop and race cars and build race cars then cause otherwise I wouldn't know what I'm talking about then would I? 5mm won't make a difference on the wheel studs. Many aftermarket wheels have that large a difference in them vs. oem wheels in the depth of the lug nut holes. When was the last time you measured them to make sure they were ok? Right, thought not.

You have to remember that OEM also says things to cover them selves from law suits. If in the odd chance something did happen that was totally unrelated to the spacers but a wheel fell off and caused a problem they can say did you replace the bolts which had nothing to do with it and when you say no, they are off scott free. It's not all about engineering when it comes to cars, trust me on that. It's about Money and how they are going to get screwed with what they sell and tell you. If you did change the bolts then they can argue well it wasn't that parts fault then.

I would say put on longer studs as well, but you don't have to and it will be fine. I only change out studs however not for longer one's but titanium or magnesium for lighter weight. Lots of companies make some awesome studs & bolts that are super light. In many forms of racing you end up having to run entended wheel studs which protrude though the ends of the lug nuts so you can visibally see they are there and on tight during pre-race inspection anyway so in a real race condition this doesn't even apply.

[teknotikal]

Are there vendors that sell spacers(17mm) with bolts???? I have a widebody kit and in desperate need of spacers. Thanks

[White987S]

Are there vendors that sell spacers(17mm) with bolts???? I have a widebody kit and in desperate need of spacers. Thanks

Try:

www.paragon-products.com

www.wheelenhancement.com

[Tool Pants]

A 5 mm spacer is not much, less than 1/4 of an inch.

Local owner Henry put 996 wheels on his 2000 2.7 and used 6 mm spacers with the original 45 mm wheel bolts for 10,000 miles. He is still alive as is his Boxster. After I teased him long enough he put on the 50 mm GT3 wheel bolts.

I wish I had counted the number of turns he had before and after the wheel bolt change. Next time I see Henry I might just do that.

There is a rule of thumb for the number of turns when using spacers and the stock wheel bolts. I have have seen different rules.

On my 1997 with stock 17" wheels and stock wheel bolts with no spacers I counted 7.5 turns for the front.

[blue2000s]

I'm always amazed that so many people

think they know more than the OEM engineers.

My bet is Porsche engineers taking into consideration the way many of its cars are driven (Auto-X, track, twisties, tail of dragon, etc). If you were to ignore Porsche's warning to install longer bolts and only use the car for tooling around town showing off your new wheels, you'd be fine. But stress the things over a long track day and you could be in trouble. Or put a super stress on them in an emergency situation and you could be in trouble. Porsche engineers to prevent that, is my guess.

Think of the longer bolts as a way of getting new shiny bolts that help show off those new wheels and be safe. Or take your chances with advice that contradicts that of the OEM. Your choice.

Well it's a good thing that I own a Race shop and race cars and build race cars then cause otherwise I wouldn't know what I'm talking about then would I? 5mm won't make a difference on the wheel studs. Many aftermarket wheels have that large a difference in them vs. oem wheels in the depth of the lug nut holes. When was the last time you measured them to make sure they were ok? Right, thought not.

You have to remember that OEM also says things to cover them selves from law suits. If in the odd chance something did happen that was totally unrelated to the spacers but a wheel fell off and caused a problem they can say did you replace the bolts which had nothing to do with it and when you say no, they are off scott free. It's not all about engineering when it comes to cars, trust me on that. It's about Money and how they are going to get screwed with what they sell and tell you. If you did change the bolts then they can argue well it wasn't that parts fault then.

I would say put on longer studs as well, but you don't have to and it will be fine. I only change out studs however not for longer one's but titanium or magnesium for lighter weight. Lots of companies make some awesome studs & bolts that are super light. In many forms of racing you end up having to run entended wheel studs which protrude though the ends of the lug nuts so you can visibally see they are there and on tight during pre-race inspection anyway so in a real race condition this doesn't even apply.

The reason for a minimum thread engagement is to protect people from the threads stripping from the hubs, period. Here's how it works. There is a certain amount of tension on the head of the bolt holding the wheel to the hub. The force at the head is countered by the threads holding the bolt in the hubs. Each turn of thread supports a proportional amount of this force. Half the number of engaged threads and the force on each thread doubles. The local stress in the hub near the face contacting the wheel increases because the load is not as evely spread out along the depth of the thread so the total risk of thread stripping is even greater than double.

When the engineers defined the attachment of the wheels, they chose a bolt material, a hub material, a thread pitch and size and bolt length all designed for an acceptable factor of safety to protect from the head of the bolt snapping and/or the threads stripping considering the weakest possible bolt, the sloppiest possible threads and the most possible force on the bolts (lots of torque + some lateral load on the tires). This factor of safetly is typically 2.5-3.0 in this application although I don't know specifically what Porsche uses.

When you decrease the number of engaged threads you cut into this safetly margin, possibly significantly. Because there is a nice large margin, you would probably be fine with shorter threads, but my question is why take the risk?