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Correct tyre size??

So a previous keeper changed wheels from 18
to 17 . Now we getting somewhere.
I guess it is the other way round.

My car's certificate of conformity states 7.5JX17 ET40.

I am the second owner and when I bought the car, it had 245/45 R18 tyres. Not sure if the first owner changed the alloys from 17 to 18. Is there a way to check without taking the tyres off?
 
I guess it is the other way round.

My car's certificate of conformity states 7.5JX17 ET40.

I am the second owner and when I bought the car, it had 245/45 R18 tyres. Not sure if the first owner changed the alloys from 17 to 18. Is there a way to check without taking the tyres off?
What size tyres are fitted right now ??

If they are 18 then the wheels are 18 .

You CANT fit 17 inch tyres to 18 inch wheels.

Nor can you FIT 18 inch tyres to 17 inch wheels.
 
What size tyres are fitted right now ??

If they are 18 then the wheels are 18 .

You CANT fit 17 inch tyres to 18 inch wheels.

Nor can you FIT 18 inch tyres to 17 inch wheels.
The car currently has and always had 245/45 R18 tyres (confirmed from Leaseplan delivery note to the first owner). What confused me is the certificate of conformity (CoC) issued by Mercedes which states 225/55 R17 7.5JX17 ET40.

Not sure what are the odds of Leaseplan changing the alloys on a brand new vehicle but I will get the rims checked by a mechanic before ordering new tyres.
 
Put the VIN into a decoder site and see what the car left the factory with?
 
Put the VIN into a decoder site and see what the car left the factory with?
Thanks. I tried quite a few VIN decoder sites and most of them do not show the wheel details but managed to get this from one of the sites:

088Control code 330 x 32 - Brake with 18 inch tires
R31Light-alloy wheel 5-spoke-design 18" all-round

My wheels look like R31 so I guess this must be it. :)
 
Not sure what are the odds of Leaseplan changing the alloys on a brand new vehicle...

Nil.

You have 18" wheels on the car. Fit new 18" tyres in the same size as you have now. I can't comment on the relative characteristics of the Michelins you are considering, I'm afraid, because I've never driven a Mercedes on Michelins.
 
You mentioned playing with tyre sizes. You really need to know what you’re doing - and why - my advice would be to keep it simple and replace like for like.
 
You mentioned playing with tyre sizes. You really need to know what you’re doing - and why - my advice would be to keep it simple and replace like for like.
I intend to replace like for like.

The confusion I have is/was owing to the conflicting information in Mercedes CoC and leasing company delivery note to the previous (first owner).
  • The CoC states the tire/wheel combination as 225/55 R17 97Y (7.5Jx17 ET40) --> 17"
  • Leaseplan's delivery note to the first owner states 245/45 R18 100Y --> 18" (also the size of the tyres on the car currently)
Searching through an online VIN decoder I see the stock car came with an 18" ALLOY WHEEL 5-SPOKE DESIGN ALL-ROUND

So I reckon the CoC is wrong/the source of confusion. The car has 18" tyres so will replace with 18".
 
I intend to replace like for like.

The confusion I have is/was owing to the conflicting information in Mercedes CoC and leasing company delivery note to the previous (first owner).
  • The CoC states the tire/wheel combination as 225/55 R17 97Y (7.5Jx17 ET40) --> 17"
  • Leaseplan's delivery note to the first owner states 245/45 R18 100Y --> 18" (also the size of the tyres on the car currently)
Searching through an online VIN decoder I see the stock car came with an 18" ALLOY WHEEL 5-SPOKE DESIGN ALL-ROUND

So I reckon the CoC is wrong/the source of confusion. The car has 18" tyres so will replace with 18".
You’re making this very complicated. Read the size(s) from the side of your tyres. They may be different front to back (staggered setup) but must be the same left to right on each axel.
 
So I reckon the CoC is wrong/the source of confusion
From the .gov website..
"Means a document which is issued by a manufacturer, certifying that a vehicle has been produced under the same production processes and systems as an example of the type which has achieved Type Approval."

It doesn't mean the vehicle is identical to that submitted for testing.
 

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