New wheels delivered with a wrong offset

[Fly4ever]

I just received my new BC Forged wheels and even though they seem really stunning I noticed on the labeling outside the boxes that ET (offset) is way different from what I ordered.

I ordered a pair of 20x8 ET34 for the front and 20x10 ET49 for the rears. The ones I received are 20x8 ET+16 for the fronts and 20x10 ET+34 for the rears.

No one knows why the factory decided on their own to change the ET value for both front and rears as almost certainly the shop I placed my order with ordered them correctly according to
what I wrote in my ordering mail.

I need to know before escalating the situation any further, what exactly means in real life such an offset difference and how the car behavior will be affected because of this, if it's affected at all anyway.
Also I would like to know why Porsche allows only such a small margin of offset difference for our car,30~34 for the front and 47~51 for the rear for the 20" size wheels.

To all those of you having any knowledge on swapping wheels sizes, will the wheels I received even could be installed on my 4S without the need of any additional equipment (such spacers for example)?

Many thanks in advance for any kind of information on the subject.

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[sor]

The sizing you got looks like it will sit about identical to the stock 22s fender-side and being 1" narrower all of that extra space is on the suspension side. This might be where the idea to move your selection came from, some calculator assumed 22s.

22 x 9 ET29 vs 20x8 ET16 = identical fender-side, 26mm more clearance suspension-side
22 x 11 ET47 vs 20x10 ET34 = identical fender-side, 26mm more clearance suspension-side

however, comparing to stock 20s they are 15-20mm more aggressive:
20 x 7.5 ET32 vs 20x8 ET16 = 22mm extra fender-side, 10mm more clearance suspension-side
20 x 10 ET49 vs 20x10 ET34 = 15mm extra fender-side, 15mm more clearance suspension-side

At any rate, the variation between even the stock wheels might give you an idea about how much this actually matters.

 

[pm4s]

No experience with swapping wheels as I’m 100% stock guy but I’ll add my 2 pence.
The wheels you have received have a lower offset from the wheels you have ordered this means specifically your wheels will stick out:
18mm in the front
15mm in the rear
In theory this means
1) extra load on the suspension/bearings/etc. (always try to visualize in extreme scenario, push the wheels out 1m in your mind, what happens to the components?
2) rubbing on fenders under suspension compression, full lock, extra weight, low mode in suspension, etc.
In practice I can’t tell as I have no experience what I can tell is that spacers you mention will not help as their function is the opposite of what your problem is, spacers would move the wheels further out.

 

[sor]

Considering that they sit identically to the stock 22s but have more clearance suspension-side due to being narrower, I wouldn't expect any problems as far as brake/suspension clearance or rubbing of fenders (otherwise the stock 22s would have issues).

Any swap of any kind is going to have some minor change to handling characteristics (and range) but I really doubt you will run into an issue here, considering just how different even the various stock options are.

 

[Fly4ever]

Thank you guys for your valuable inputs,are almost identical with what I've just been told by the wheels shop I ordered them from.

Besides keeping the wrong wheels I was given the option to send them back on their expense and at the same time they order a new set for me according to the actual dimensions primarily ordered.Another option was to install them and see how they look,if I still don't like them to also have them returned and replaced.If I decide to keep them the shop will refund me an amount as a compensation for the hassle and additionally there will be gifts to expect from them.

Needles to say the shop took the whole responsibility for the mistake and everything and of course I accept their sincere apologies as they admitted neglecting to compare what they order for me and what they received from the factory prior sending the shipment to me.

Unfortunately I'm yet unable to install the wheels to see how it looks because my tires (Goodyear Ultragrip Performance GEN-1) are still on order and I'll not get them for at least another 10-15 days so I don't know how it will look on my car.But I think it won't be that good, as the 20" wheels are not as sporty and aggressive the 22" are nevertheless they'll still be "sitting" at the out-most end of the fender,something that's the "normal" physical position of the bigger rims/smaller tire profile combination.I think it will look like a Ford Raptor somehow...!

Besides,I'm also more of a stock guy myself,that's why I decided to stuck with the original numbers.
I'm also considering how the car will react concerning Rear Axle Steering with 20" wheels so much outboard from what the car "knows" as the specific wheel's dimension normal/official position.
More likely the efficiency will also be affected as well with the new wider stance...

Almost certainly I'll go with the replacement option the shop gave me even though I'll have to wait for another 6 weeks to get my wheels,at least will be what I really wanted at the end.

BTW this is an outstandingly great shop in EU...!!!I definitely recommend them, Truly Great Professionals!!!If not The Best,definitely one of the Best in whole continent!And they ship also worldwide!Anyone interested PM me,the shop is in the Netherlands.

 

[sor]

Just something to consider - the stock 22" wheels don't stick out of the fender at all, so I wouldn't expect these to either. They won't be tucked in like the standard 20s though. It's good they are taking care of you!

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