Hey guys,

This issue has persisted now for 2 seasons, it started last year on me and there are specific conditions it seems for it to be replicated. I have lots of variables with a few controls and I'm hoping someone here can look at what's happened, what I've narrowed it down to and has had similar experience.

I've had at least 5 different tire shops look at the issue and 2 Porsche mechanics (2 different shops). I've had the wheels balanced and re-balanced, I've had alignments twice, I've even replaced the front tires with a different set from the same manufacturer as I told the fronts were "cupped" but didn't seem that was the case.

1. The setup

a)22" rims, 9" front, 10.5" rear - so yes... staggered, forged barrels concave/deep dish design.

b)Nitto Nt555 tires in front, Vredstein SUV Sessanta uhp tires in the rear. profiles/size match almost perfectly so the rear (or front) isn't higher or lower by X %

c)Wheel spacers, front and rear. Unfortunately the wheel manufacturer lied to be during purchase and the offset was NOT sufficient enough to clear my calipers so I was forced to use spacers. They're classified as "slip on" and made of a high quality material. Basically, I didn't cheap out on them and they were bought from a respectable and well-known manufacturer i.e Pelican/Vertex/Suncoast, etc.

2. The controls

a)This issues does NOT happen with my winter tires
i)no spacers on winter tires
ii)winter tires are same tread pattern and size and use the stock rims

b)It only happens when I exceed 65 mph and it increases in it's vibration and shakiness" accordingly as speed increases. It gets so bad at >80mph it takes two hands and it's violent.
i)When turning or when going through bends in the road it "seems" to
either subside or at least become much less worse
ii)it doesn't stop when braking, only deceleration will stop it

c)Persists on different road types - concrete, asphalt, gravel, etc.

d)I have tried disabling PSM, it's no different at all

Some other observations:

1. It seems to be more prevalent when it has rained or is raining
2. It comes and goes, it is not constant.
3. It doesn't get any better, or worse after the tires have "warmed up" or on
warm or cold asphalt

So with this, I have potentially eliminated drivetrain, suspension, etc. and it almost is exclusively one of the following issues:

3. The list of potential issues/contributing factors

1. Staggered setup - though I've read staggered is fine on AWD cars and specifically Cayennes, the only issue is torque vectoring or cornering, wouldn't cause extra wear and wouldn't present itself in this case.

2. Different tread patterns - front and rear wheels are "incompatible" but I'd think it would always be there?

3. Spacers - because there are essentially two additional planes for some pretty high-speed components to mate to instead of just rim to hub maybe there are issues with it being tightened down correctly? But again, wouldn't this always show up?

4. Cupping - don't know enough about tires to comment on this but the car doesn't sit very long i.e no more than 24 hours without moving, and I did replace the last front NT555 tires so the chances of two sets cupping would be low I'd hope?

5. Bent/warped rim - I would think this would always show up though?

6. ???

Would love some help guys. This is driving me nuts. I'm not in a position to go and replace a whole set of rims and tires at this point.

I'd also like to note that the ball joints show some wear, which I'll be doing in the next couple months but again, this seems like it's a hub to tire issues, with it being either driven by spacers, tires, rims, balancing, etc.

I'll owe whoever has a fix a nice bottle of maple syrup!


TLDR - vibration in steering wheel, comes and goes, seems worse in wet conditions, doesn't happen with a different set of tires which have identical pattern and aren't staggered, braking doesn't affect the severity, cornering seems to, only happens above a certain speed. Have been re-balanced too many times to count and alignments done

 

1. What are the wheels made of? Are they alloy/mag or heavy cheap chrome plated. a lot of the shiny chrome rims out there are so heavy even if balanced they vibrate because the suspension can't dampen out the bumps in the road. The higher the frequency of the shock absorber (faster you travel) the more pronounced it becomes.

2. Do the spacers centre the rim? They should have a lip either side to ensure the rim is located correctly. If the spacers don't have this and are simply spacing the rim you will never be able to centre the rim correctly.

 

Your issue is 1 of 3 things and the wheel is moving around at higher speed.

1. How thick are the spacers and what type are they? Are they the one that bolt to the hub with special bolts and d then the wheel Lug bolts thread into the spacers or are they the kind that just get sandwiched between the wheel mounting face and the rotor hub? Both types of spacers need to be hub-centric designs where the spacer centers on the wheel hub cap enter flange and the wheel centers on the spacer flange and they need to be 71.6 mm and should be exact to where they don't slide together fully without the Lug bolts being tightened or the tolerances are too loose. If using a thinner sandwich style spacer, many of these don't have the wheel centering lip on the outward side, but they're thick enough to prevent the one on the hub from engaging the wheel. Also, with any sandwich style spacer you need to be running longer wheel bolts by the amount of the spacer thickness.
2. 2nd possibility is that you have a mismatch between the seat of the Lug bolt and the seat of the wheel. Porsche OEM is a ball or radius seat (rounded) but some aftermarket wheels use a tapered or conical seat. If the barcode out is one type and the wheel, the other, the bolts won't seat and torque down to the wheel holes properly and allow the wheel to move around at speed. If this was the issue, the seats in the wheels may be damaged now and should be checked very carefully before continuing to use them.
3. Last possibility is that the wheels were manufactured with a center bore of something other than the correct 71.6mm necessary.

Let us know what you find.

 

Here's a picture of them. They are heavy, but I'd honestly say no more heavy than the stock rims. They do have a chrome outer lip and pinstripe and it does seem to be a bit "cheap" as it did scratch easily a few times.


Front/rear - note the deep dish in the rear



Fronts


The spacers have a sort of "lip" that does seem to centre the rim but there could be some play in this case.

Unfortunately I can't tell you who manufactured the wheel spacers I use on the front, I sent an angry email to Zenetti about my fitment issues, and various hardware not being included so they sent out "custom spacers" to which I ensured they understood the fact they needed to be hub-centric and specified the bore. I am running longer studs in the front and rear to accommodate spacers. I can't seem to find the emails unfortunately for my order of the spacers for the rear and the one from Zenetti doesn't give any information. They are the slip on style which a lot of people tend to shy away from. The fronts are 10mm, and the rears are 15mm. The rears are H&R which can be found here. https://www.uspmotorsports.com/Wheel...olts-15mm.html

This is something I'll have to get the tire shop to look at. I know exactly what you're saying but it's something I've likely overlooked. This is a good point and definitely a huge safety concern.


I'm 100% certain the centre bore is correct unless documents I received from the distributor and the manufacturer both were incorrect.

I do have to take the Cayenne in for some Control Arms and a few other minor things so since an alignment has to be done and the wheels are being popped off I'll ask them the questions that you guys have brought up here.

In the future, as I will be replacing these wheels next season (unless the seats in the wheels are damaged, in which case I will be replacing immediately), what should I avoid or how can I ensure that I can avoid these sorts of issues down the road? Some of the "run of the mill" rims I found which a lot of 955/7/8 owners use I have found to just be so plain or boring in my eyes, I am partial to the staggered, concave, 3 piece look. Has anyone ever tried out or heard any good/bad things about Niche, Lexani, AC, Rucci, DUB, Fondmetal, Koko Kuture, Giovanna, Diablo?

 

Have you checked the age of your tires? The close up of your rear tire indicates 4013 , which means manufactured in week 40 of 2013 , which puts it at almost 4 years old, which should still be OK. Check the date on the fronts to see the manufacture date.
I have just replaced the two front tires on my Cayman which were fitted in 2015 which turned out to be from a batch manufactured in 2009!
I had vibration at about 100km/h , tried balancing and also suspected a bent rim.
The tires still looked healthy and had plenty of tread, but due to age I guess used to deform at speed and create vibration.
Replaced tires and vibration went away.
Tire life is indicated at 5-10 years depending on the manufacturer.

 

I'll have to check the rears. The fronts were replaced (the close-up is of the fronts) and they are now Jan '16. If it was a tire issue I was always apt to blame the Nitto's instead of the Vredstein but good point.

 

Personally, I never think it's wise to run a different tire on the front of a vehicle than the rear. Rubber compounds, grip, tracking, etc can be significantly different between 2 different types of tires and can create a dangerous handling situation. As an extreme example, it's like putting snow tires on only the front of a front wheel drive car since those are the wheels that need traction to move the car, and then being really surprised when it does an about-face and the rear comes around on snowy corner. Personally, I'd get 2 new tires to match the 2 that have more tread or the 2 you like better, and put the other 2 on craigslist - someone will buy them.

 

Those are good quality rims, I wouldn't worry about the weight of them.

It sounds like the spacers are correct but still worth confirming they are the correct size. Check that they centre securely on the hub as well as the wheel.

If a balancing of the wheel passes I wouldn't be worrying about the tyres or rims.

I know my CTT is temperamental with tyres and pressures. It develops a clunky engagement of the driveline when taking of from a standstill. Previously fixed this by installing new tyres on all corners. I believe it is to do with the PSM and slight variations in wheel speed. If your staggered wheel/tyre combinations are not perfect the ecu thinks you are loosing traction on the slower turning wheel.

 

hunter road force balance all four.

 

You make a good point. This is primarily my highway car and if this was tracked or anything I most certainly wouldn't have mixed. Unfortunately Vredstein didn't make a tire that was going to work with my setup so I had to go with something that would. The Nitto's are LOUD. I personally will never buy a Nitto again. Also - considering the price of 2 new tires, changeover, and the fact I'm going to be getting new wheels next year, I'm shying away from needlessly spending money. I tried to sell the old Nitto's (before I found out they were cupped) and they were listed for months and months with not so much as a bite.

You make a really good point. These have been road force balanced and I trust the guys at the shop I go to without hesitation, not sure what brand their machine is but they're the guys that do the Lambos and Ferarris around town. So it does seem to lead back to either spacers whether they're centering on the hub or the rim to them, different tread pattern, or the seating of the lugs. This has narrowed it down a good bit. Thanks. Will keep you guys posted. Once the 911 is out of the shop this pepper is going in and I'll have that bottle of maple syrup ready

 

I've actually been very pleased with Nitto tires. I run Invos on both my 928 & 997 (multiple sets) and have their 450 (maybe 455) on my pick-up, which have been a great all season S/T tire.

 

You've never had any problem with sound or performance? I'm running the NT555. Across multiple forums there have been a lot of comparisons between the Invo and the NT555 and the ride quality and road noise is far worse in the NT555. I suppose I shouldn't paint one manufacturer with the same brush.

I would stay away from NT555's on any Cayenne/Macan.

 

It's actually a 420 I'm running on my truck


And although I can hear the tread with the windows down, it's quieter than the Corsa Sport exhaust that's on it.

Regarding the Invo, the tread design is very different than that of a 555 and I've been super pleased with them. Tons of rubber on the outer edges for cornering grip and they're also asymmetrical as opposed to directional, so they can be rotated side to side.

 

I love maple syrup

my guess is that the ball joints being lose, and the added variation in the spacers, etc are causing a harmonic frequency to start up. Cupping is usually caused by alignment and worn suspension components (I.e. Ball joints) but this will exacerbate it starting to wobble. The other issue that mitigates cupping is rotation. But with directional tires, you can't rotate. I would think if the spacers are extending the wheels out a half an inch or more then the dynamics of the whole "setup" could be affected. . For sure you need to replace the ball joints before doing anything. Another thing to check is whether the lug nuts, which I'm assuming are longer for the staggered set (due to spacers) are all the same length AND material. Any differences would cause it to be out of balance. Also, just to make sure the circumference of all your wheels ARE the same, measure and compare with a string. My guess is if they aren't within 1/4 inch I'd consider

As a last resort I believe you can balance the wheels on the car, which would take all the unbalanced suspension and wheels into account.

 

Oh, and one more thing, make sure to check how round the wheels and tires are. good tire places like discount tire will be able to check the "run-out" on the tire/wheel combo, and be able to tell you the breakdown of rim and tire run-out. I've had tires there were not circumferential