What is the procedure to legally fit bigger wheels on your car?

Transportation, Travel and Trips
1
My car came on 18" wheels from the factory and that is maximum size allowed. I'd like to fit 20" aftermarket wheels on the car legally so I don't have problems with police or MFK.

I'm new to Switzerland so I have no clue how to do this. In my country you buy the bigger wheels and you make sure they come with a TÜV certificate, confirming the wheels fit your specific car model. Then you visit your local MFK/road office with wheels on the car and the aforementioned TÜV document in hand to homologate the wheels. They take a quick look at the wheels and papers and write down the new wheel and tyre size in the car registration document or COC document. They write down just wheel and tyre sizes and not what brand the wheels are. So let's say in couple of years you can swap the wheels for another brand without doing another inspection, you just have to make sure they are the same size as your previously homologated wheels. How do I do this in Switzerland? Thanks

2
Option 1) You buy them from a Swiss source. They come with a paper titled "ASA-Prüfbericht Räder". Done.

Option 2) You buy from Germany, they come with an ABE and correponding TÜV-Prüfbericht. Needs MFK visit, will be approved.

Option 3) You buy from Germany, they come only with a TÜV-Teilegutachten or just a TÜV-Gutachten. Needs MFK visit, might not be approved.

Option 4) You buy from abroad and they come with an ECE Regulation 124 Type approval. Done.

Option 5) You buy them from anywhere and no papers or none of the above papers are delivered.

https://www.felgenshop.de/blog/muss-...tragen-lassen/

Option 4, won't work as it AFAIK does not apply to rim sizes which are not covered in the cars type approval / CoC.

Option 1 is the easiest but may cost more than when sourced from abroad.

3
AFAIR (long time ago in CH), though, if the circumference of the tire de-/increases by a certain %-age, the speedometer has to be readjusted, no?

4
Important to know is that you get an AG registration plate, when you fit bigger wheels, lowered suspension and gull-wing doors.

5
The speedometer must read not less than your true speed and not more than 10% + 4 km/h over true speed. Example: If you go a real 60 km/h the speedometer is allowed to show anything from 60 km/h up to 70 km/h. If the speedometer is within this prescribed accuracy nothing has to be changed. If it is outside, it must be adjusted.

Independently of that you are allowed to change the overall drive train up to +/- 8% Simpler to switch a gear on a motorcycle, on the other hand more ETRTO approved tyre/rim combinations for cars.

6

Seriously? My AG plates included negative camber in all wheels for free

7
Don't forget the fetching white socks to flash as you step out of your high-performance automobile wowing your desired gender

8
Thank you man. So with option 1 you just have to keep the ASA document in the car at all times and cops won't bother you? Also insurance companies in case of an accident?

What about abroad? Will German/Italian cops require a COC document with new size listed in it or they will be satisfied with the ASA document as well?

9
If they have the certificate then they're within the sizes allowed by the manufacturer in the first place, so in practice you'll only ever need them for the MFK, but if even if they're listed on the grey card then your insurance will need to be informed as well.

They won't even ask.

But despite all of this you're not going to be able to fit rims which are larger than the originals unless they were available or allowed as a manufacturer's option in the first place. Is a 20" wheel listed in your handbook? If not then forget it.

10
The approved rim and tyre sizes are not listed on the gray card. They are only listed on the CoC or in the Swiss type approval database TARGA.

In addition, rim sizes which are listed on the CoC (a.k.a manufactures options) do not need any papers at all. They are approved by default by virtue of beieng listed on the type approval itself. Only sizes which different from those need additional papers, special approval, or entry in the gray card.

I never informed the insurance when I fitted an aftermarket part which was approved by the MFK and entered on the gray card (not everything must be entered into the gray card, for more details see ASA 2a for cars or ASA 2b for motorcyles). Maybe I should check my insurance terms and conditions, but as far as I am aware no Swiss has ever informed the insurance about new wheels, exhausts, or modified springs.

If you use larger rims you will need tyres with a smaller cross section height. Been there done that and ended up with a bit less diameter overall as well. Mostly for the look, plus a bit more low speed torque/power but total crap with speed bumps, garage driveways, and ferry ramps.