Will I run into trouble when I get 21" aftermarket wheels if I don't have the wheel arch extension option from the factory (on an S e-hybrid) ? For instance rubbing or maybe something else of unwanted behavior ?

 

The wheel arch extensions serve two purposes. One is aesthetics, giving that "flared" look around wheel wells. The second is with wider tires, they tend to stick out a bit more. The arches are suppose to catch some of the debris kicked up by the wider tires. If your new 21" don't stick out past the the fenders then you won't need them. But with most larger wheels you want a more aggressive stance (wheels pushed out more) and hence why you see most of those cars with wheel arches.

 

What Hoiya said is spot on.

 

Well said HOiYA ^^

My CTT came with stock 19" wheels/tires from the original build.
Stock 19's do not come with wheel arch extensions.
I had my Porsche dealer install new Turbo II wheels (21") when i bought.

Interestingly enough, the Porsche configurator includes (requires) arch extensions with certain wheel choices.
IIRC it's specific to 20x9.5" wheels and all 21s (usually 10" wide).

I discussed with a few Porsche reps before purchasing to ensure i was ok.
Also, I figured i would add the arch extensions if i saw any hint of problems.
To date, I've seen no issues.
I run 20x10s in the winter, and 21x10s in the summer.

Wheel arch extensions are mostly cosmetic unless you have 20 or 21" tires AND wheel spacers.
In that case, i would strongly recommend.

Good luck!

 

Clear as a whistle. I will NOT be getting the wheel arch extensions then !

 

I saw on another thread you were asking about 21"/22" Caractere or Cargraphics wheels. I am not sure what the offsets are for these or whether they are built to order. You might want to nail down your wheel choice and then decide if you need the wheel arches. If it were me, I would get the wheel arches to be safe. Hate to mar up the paint with debris if wheels stick out too much.

 

Indeed Hoiya, just ordered a few days ago. Now in the process of fretting over some options and 20" or 21" wheel choices. And one decision might very much spill over to another as you mentioned :-)

But what I take away from this very helpfull thread if I read correctly (?):
- I do not NEED extensions for safety or regulation reasons
- I can install them afterwards should I wish so

 

You are correct on both points. The road debris part is more important. This will be dictated by your wheel choice and offset chosen. On my current 21" setup, it came with 5mm spacers so I think the arches were needed to catch road debris. I just ordered a new set of 22x10.5 ET55 and they will be flush with the fender flares. So it really depends on your wheel/tire width choice and offset.

You might also want to check if ordering he arches are cheaper now or later. Also, factor in if you want them to be painted to match the car exterior color.

 

I've swapped wheel arches and to be honest, it is very minor (few mm) difference in actual width. Not sure how much actual benefit there is with road debris protection. If debris is a big concern, mud flaps would have more benefit. There is an off road version of the arches though that do stick out appreciably more though that would probably have a greater effect.

 

IIRC the difference (wheel arch extension vs. none) amounts to approximately 1/4 inch.

I could only assume the sport design arches are a bit more complicated for install.
However, they actually appear to provide a more significant extension.