I have a C4s coming in a week, I am thinking about to order a extra set wheels/winter tires which bring me some questions.
I am thinking to get a set of spacer, (don't know what size I need, 5mm front - 15mm back?) purely for the appearance purpose.
The question is should I order the same offset as the 19" Carrera S II which is come original, so that I leave my spacer on my car forever or order a correct offset then I don't need the spacer in Winter. Are they easy to put on and remove?
Anyone has this thought for your car and what you did? why?

Another question is why we have the 305/19/35 in the back and 235/19/30 in the front? They are two different diameter tires right? Sorry if my question is stupid.
I will drive in the Winter, but I don't think I will drive when snow. Should I order 19" or 18" wheels or it doesn't matter?

Thanks ahead.

 

snow tires usually recommended on 18" rims but if you will drive on summer tires in winter - it is your call.
as you are in NJ I am not sure how will you avoid snow or ice on the road if you for real going to drive it all winter long. I would not do that when it snows, just to avoid salt damage. But if you really going to drive it on snow - get 18" rims with Michelin PA2 tires or similar.

For summer tires 19" looks better, 18" rides smoother and less bumpy.

For exact rims offsets on wide body C4s you can look at tirerack site - they have it showing if you select right car model.

 

Diameters are the same 19 inches. The 35/30 is the percent or aspect ratio. The rear sidewall is 35% of 305mm and the front is 30% of 235mm.

 

Thanks for quick answer.
No, I definitely use winter tires for winter but wondering if I need to use 18" wheels for non snowing road surface. I believe neither 18" or 19" wheels will comfort the ride enough. If I don't need to, I stay with the 19". I don't know about the width? Should I keep the same 235/305 for non snow driving?
I sure won't drive when snowing unless it starts when I am on the road. I have other cars for that purpose.
BTW, is it necessary to do wheels alignment every time after I change to a different size of wheels?

 

But 35% of 305mm is not the same as 30% of 235mm
Is that the height measure between the wheel and the end. So if the inside diameter is 19" for both tires. the the 305 is bigger right?
Sorry again if I asked stupid.