** Spacers Accredited **

[RascalRuss]

Acting stupisd here, so sorry, but are the spaces for looks only or do they have a performance effect??

many thanks

Russ

[RascalRuss]

By the way, just to add a note about bolts, you actually only need to screw in at a depth that is equal to the width of the bolt. Any extra does not make a massive difference. We also proved this in a number of University experiments while doing my engineering degree

cheers

Russ

[986Jim]

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?

Lol thanks for the reply, very informative. :rolleyes:

5mm spacer is fine with the stock lug nuts. Been done 10,000 times before with 0 problems. Wish to continue this argument at all? Maybe you can re-read tool pants and my posts.

Regards,

[blue2000s]

By the way, just to add a note about bolts, you actually only need to screw in at a depth that is equal to the width of the bolt. Any extra does not make a massive difference. We also proved this in a number of University experiments while doing my engineering degree

cheers

Russ

That's a pretty good rule of thumb, but you still need to consider the mating materials to make the correct determination.

[blue2000s]

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?

Lol thanks for the reply, very informative. :rolleyes:

5mm spacer is fine with the stock lug nuts. Been done 10,000 times before with 0 problems. Wish to continue this argument at all? Maybe you can re-read tool pants and my posts.

Regards,

Just because something worked for you in the past in a different situation doesn't mean it will work every time. You need to understand the risks of a situation in order to make a good decision. I hold ToolPants' opinion in very high regard based on the knowledge he's shown on this and other boards but everyone takes risks without realizing it at times.

[blue2000s]

Acting stupisd here, so sorry, but are the spaces for looks only or do they have a performance effect??

many thanks

Russ

Most folks do it to fill out the wheel wells. It does shoften the suspension a bit because it increased the lever arm of the suspension. I doubt you'd notice any difference.

[Jinster]

I found the following info, don't know what the actual source was

"It should also be noted that for European wheel nut and bolt engagement approval there must be six turns of thread engagement for M14/M12x1.5 thread pitches and nine turns thread engagement for M12x1.25 thread pitch. This is particularly important when using any kind of wheel spacer."

[pomocanthus]

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.

Loren and other gurus,

I know this is an old thread but a lot of good information in here. I recently got a good deal on some new staggered 18X8 and 18X10 with 225/40/18 and 265/35/18 mounted on them. These are the new Turbo design knock-offs which the sellers guarantees t Boxster fitment. Of course he didn't mention the need for spacers. In any case I want to mount them on MY99 Boxster. In looking at the TSB 4440 that you recommended, the table on page 4 mentions nothing about spacers for this setup. It does mention that Snow Chains cannot be fitted and there is also footnote 6 concerning parking brake cables. Am I missing something here? I KNOW I need some kind of spacers for the rears because when I dry-fitted them, the rims were right up against the struts (I replaced my struts w/ RoW030 if that makes a difference).

I also found other threads here that other people used different size spacers (7mm) that are not called out in the TSB. I am looking for a little guidance on what I would need to make these rims fit properly and more importantly safely.

Thanks in advanced for you help,

Hung

[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.

Loren and other gurus,

I know this is an old thread but a lot of good information in here. I recently got a good deal on some new staggered 18X8 and 18X10 with 225/40/18 and 265/35/18 mounted on them. These are the new Turbo design knock-offs which the sellers guarantees t Boxster fitment. Of course he didn't mention the need for spacers. In any case I want to mount them on MY99 Boxster. In looking at the TSB 4440 that you recommended, the table on page 4 mentions nothing about spacers for this setup. It does mention that Snow Chains cannot be fitted and there is also footnote 6 concerning parking brake cables. Am I missing something here? I KNOW I need some kind of spacers for the rears because when I dry-fitted them, the rims were right up against the struts (I replaced my struts w/ RoW030 if that makes a difference).

I also found other threads here that other people used different size spacers (7mm) that are not called out in the TSB. I am looking for a little guidance on what I would need to make these rims fit properly and more importantly safely.

Thanks in advanced for you help,

Hung

What are the offsets of the new wheels?

[pomocanthus]

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.

Loren and other gurus,

I know this is an old thread but a lot of good information in here. I recently got a good deal on some new staggered 18X8 and 18X10 with 225/40/18 and 265/35/18 mounted on them. These are the new Turbo design knock-offs which the sellers guarantees t Boxster fitment. Of course he didn't mention the need for spacers. In any case I want to mount them on MY99 Boxster. In looking at the TSB 4440 that you recommended, the table on page 4 mentions nothing about spacers for this setup. It does mention that Snow Chains cannot be fitted and there is also footnote 6 concerning parking brake cables. Am I missing something here? I KNOW I need some kind of spacers for the rears because when I dry-fitted them, the rims were right up against the struts (I replaced my struts w/ RoW030 if that makes a difference).

I also found other threads here that other people used different size spacers (7mm) that are not called out in the TSB. I am looking for a little guidance on what I would need to make these rims fit properly and more importantly safely.

Thanks in advanced for you help,

Hung

What are the offsets of the new wheels?

Loren,

I was told the offset is 50 and the guys at the tire shop insists that they've installed the same rims on Boxsters before. Unfortunately, I bought these online so I can't bring the car to these guys. I don't know if that's for all four rims or not. I couldn't find stamps of rim size or offset. Is it possible for both fronts and rears to have same offset?

Thanks,

Hung

[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.

Loren and other gurus,

I know this is an old thread but a lot of good information in here. I recently got a good deal on some new staggered 18X8 and 18X10 with 225/40/18 and 265/35/18 mounted on them. These are the new Turbo design knock-offs which the sellers guarantees t Boxster fitment. Of course he didn't mention the need for spacers. In any case I want to mount them on MY99 Boxster. In looking at the TSB 4440 that you recommended, the table on page 4 mentions nothing about spacers for this setup. It does mention that Snow Chains cannot be fitted and there is also footnote 6 concerning parking brake cables. Am I missing something here? I KNOW I need some kind of spacers for the rears because when I dry-fitted them, the rims were right up against the struts (I replaced my struts w/ RoW030 if that makes a difference).

I also found other threads here that other people used different size spacers (7mm) that are not called out in the TSB. I am looking for a little guidance on what I would need to make these rims fit properly and more importantly safely.

Thanks in advanced for you help,

Hung

What are the offsets of the new wheels?

Loren,

I was told the offset is 50 and the guys at the tire shop insists that they've installed the same rims on Boxsters before. Unfortunately, I bought these online so I can't bring the car to these guys. I don't know if that's for all four rims or not. I couldn't find stamps of rim size or offset. Is it possible for both fronts and rears to have same offset?

Thanks,

Hung

The front rears should have different offsets (on 18" wheels).

If they are Porsche wheels they will be marked on the wheels.

[pomocanthus]

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.

Loren and other gurus,

I know this is an old thread but a lot of good information in here. I recently got a good deal on some new staggered 18X8 and 18X10 with 225/40/18 and 265/35/18 mounted on them. These are the new Turbo design knock-offs which the sellers guarantees t Boxster fitment. Of course he didn't mention the need for spacers. In any case I want to mount them on MY99 Boxster. In looking at the TSB 4440 that you recommended, the table on page 4 mentions nothing about spacers for this setup. It does mention that Snow Chains cannot be fitted and there is also footnote 6 concerning parking brake cables. Am I missing something here? I KNOW I need some kind of spacers for the rears because when I dry-fitted them, the rims were right up against the struts (I replaced my struts w/ RoW030 if that makes a difference).

I also found other threads here that other people used different size spacers (7mm) that are not called out in the TSB. I am looking for a little guidance on what I would need to make these rims fit properly and more importantly safely.

Thanks in advanced for you help,

Hung

What are the offsets of the new wheels?

Loren,

I was told the offset is 50 and the guys at the tire shop insists that they've installed the same rims on Boxsters before. Unfortunately, I bought these online so I can't bring the car to these guys. I don't know if that's for all four rims or not. I couldn't find stamps of rim size or offset. Is it possible for both fronts and rears to have same offset?

Thanks,

Hung

The front rears should have different offsets (on 18" wheels).

If they are Porsche wheels they will be marked on the wheels.

FWIW, I ended up adding 23mm spacers from FVD on the rears. The tires fill out the wheel wells much better now and I have about 10-12mm clearance to the struts. I have some H&R 7mm on order for the fronts although they seem to fit just fine w/o spacers.

[sdharmani]

Has any one found a post on doubling up spacers? I looked but havent found. I have 5 mm OEM spacers. I am doubling them up for the rear with 10 mm longer bolts. Does anyone know of issue with doubling up the spacer? I got longer screws to hold the spacers in place as well.

Thanks!