I have a spare set of wheels that I used on my octavia (18x7.5 et51).  The stock wheel and tyre size on my passat (same as superb) is 18x8 et44 with 235/45/18. 

 

Would the 235 tyres fit ok on the 7.5 wide rims or should I be looking at matching the width better with something like 215/50/18?  Keen to make good use of the wheels and not been overly enamoured with the cross climate performance this past summer.  Best situation would be to keep them as winters (replaced with proper winters once worn) and put a set of nice summers on the OEM rims.

7.5 * 25.4 / 235 = 81%. You're good.

235/45R18 will be a good fit for a 7.5Jx18 ET51 rim when fitted to the Superb MK3 (or Passat equivalent).

 

215/50R18 will stretch the tyre to the max on a 7.5J rim, as the ETRTO allowable rim widths are 6J to 7.5J for that tyre size.

 

Rims width for 215/50R18

https://www.toyo.co.uk/tirefinder/index/width/215/aspect/50/rim/18

 

Rim widths for 235/45R18

https://www.toyo.co.uk/tirefinder/index/width/235/aspect/45/rim/18

 

Skoda sell a 7.5Jx18 ET46 alloy rim for the Superb MK3, although the usual Skoda size is 8Jx18 ET44.

 

 

7.5x18 ET46 Trinity Alloy Rim

 

 

https://eshop.skoda-auto.cz/cs_CZ/hlinikove-disky/c/alloyWheels?q=%3ApriceAsc%3AcarType%3ASuperb%2BIII%2B%282015%2B%29&page=0

 

Edited 25 November, 20214 yr by Carlston

Thanks both. Can always rely on @Carlston for good data 😀