Have an April 2015 Superb Estate.

Currently has the Sirrus 18" 7.5J x 18 ET46 wheels with 235/45/R18 tyres.

Gives a hard uncomfortable and noisy ride (terrible Northumberland roads)

Looking to change to a set of Passat Istanbul alloys 7J x 17 ET40 with 215/55/R17 tyres for a better ride!

Using Tiresize site indicates that they should be ok.

I'd appreciate any help on this. My local Skoda dealership were less than helpful and wouldn't comment!!

Edited 18 August, 202518 Aug by PWDSCOTT
spelling mistake

215/55R17 and 235/45R18 are Superb MK3 tyre sizes, not Superb MK2 tyre sizes.

215/55R17 and 235/45R18 have much bigger outside diameters than Superb MK2 tyre sizes.

Superb MK2 wheel sizes (check the CoC (Certificate of Conformity) to be sure what wheel sizes Skoda approves for your particular car)

205/55R16 6Jx16 ET50 (winter wheel size)

205/55R16 7Jx16 ET45

205/50R17 6Jx17 ET45 (winter wheel size)

225/45R17 7Jx17 ET49

225/45R17 7.5Jx17 ET49

225/40R18 7.5Jx18 ET46

Outside diameter of tyre sizes

205/55R16 631.9mm

205/50R17 636.8mm

225/45R17 634.3mm

205/50R17 636.8mm

225/40R17 637.2mm

215/55R17 668.3mm (not Superb MK2 tyre size)

235/45R18 668.7mm (not Superb MK2 tyre size)

Edited 18 August, 202518 Aug by Carlston

Yes I made a mistake with the alloys.

Currently they are as you say 7.5J18 ET 46 running 225/40R18

I was looking to run the 7J x 17 ET40 alloys with 215/50R17 tyres or 225/45R17 but concerned that the ET40 offset would be an issue

Edited 18 August, 202518 Aug by PWDSCOTT
typo

@PWDSCOTT There are very nice after-market 7jx17 wheels with ET 45 - 49 available. Combined with 215/50R17, that would fit, look nice and reduce the speedometer offset to about zero.

Only disadvantage: The tires are more expensive than the more common 205/55r16 or 225/45R17.

For example the Mak Wolf in 7Jx17 ET48:

Edited 21 August, 202521 Aug by andrehj