I’ve just bought my first car at the age of 43. A very sensible (and luxurious) Superb 1.8 petrol estate Elegance with automatic gearbox. It’s only got 24k on the clock and I love it. I live in London and won’t be doing huge miles but when I do, they’ll be mostly motorway miles on journeys of 4 hrs plus. 

The Elegance came with the Skoda Trinity alloys and the previous owner had some Kumho WinterCraft 225/40 R18 92V tyres fitted which are showing very little wear. I can feel/hear quite a bit of road noise and I’m reading that these tyres aren’t the best for noise, fuel consumption or braking in general (especially in the wet). As the amount of miles I’ll be doing in winter/snow will be very, very limited indeed - I was looking to change tyres.

But looking at some forums (Honest John for example) there’s a lot written about the very hard ride of 18 inch alloys, the fact this car weighs over 2000kg, should never have been fitted with 18 inch alloys, and this ‘premium look’ is something manufactures do knowing that’ll it’ll lead customers to buy more and more tyres. The front end of this car is heavy etc and will eat low profile tyres like this for breakfast. 

SO - I was thinking of changing to 16 inch alloys and a suitable tyre and maybe putting the Trinity’s onto eBay or similar. Does anyone have any thoughts or experience re this. I’m not too bothered about looks (although the Trinity‘s look very nice) - just more interested in ride comfort, road noise and fuel economy.

I’m also not sure what 16 inch alloy would fit. I’m mindful of keeping the Speedo accurate and I LOVE the park assist automatic parking function and wouldn’t want to throw that out. Any help/advice much appreciated.
 

We have a S II from 2014 and I change from summer 18" to winter 16" regularly. The 18" ride comfort is harder but not too bad. The 16" is definitely smoother as you have more rubber to help the suspension. The S II weighs 1600 kg. Its fully loaded weight with passengers and luggage is permitted to be around 2200 kg.

 

I would probably keep the 18" wheels untill the current tyres are worn down, unless the tyres are very old going by the DOT number on them as your car has only done 24000 miles. Winter tyres in the summer are a little worse compared to pure summer tyres, but defintely help in on slippery roads even if London does not see much snow.

 

The S II is o.k. with 205/55-16 tyres and the manual states an ET 45. I had bought a set of Skoda 16" alloys and hated the look - the wheels were sitting about 2 cm within the body and it looked as if the wheels were just far too small. I then sold these and bought a set of VW alloys with an ET 37 - Road America - which makes the 16" look as flush as your current 18" wheels.

My (Elegance spec') car came with rather nasty looking 16" wheels rather than the correct 18's.  They all had new tyres so I ran them until they needed changing (about 2 years), I bought the car as a workhorse so didn't mind the "whale on castors" look.

When the tyres came to need changing I found a set of better looking wheels in 17" as I didn't want to go to 18" with the elastic band tyres, the comfort on the 17's is not too different to the 16's so I think a good compromise.

I was tempted to go up a one step on the profile but didn't, still wish I had, personally I think a slightly beefier sidewall looks better (don't know where this fashion for virtually no sidewall has come from).

My calculations indicated that this would make my speedo' reading more accurate (as ever they read high as standard) rather than making it read low although, obviously, I would have checked that if I'd gone that way.

BTW, as long as you stick to the recommended profile you're speedo' reading won't be a problem, the outer tyre diameter will be the same

 

Not sure why the weight of the car would be an issue in wheel size choice, could argue that a heavier car gives a better sprung:un-sprung weight ratio giving the suspension an easier life.  Likewise don't quite see why low profile tyres would get 'eaten' any more than un-low profiles due to weight.

 

When I changed my wheels I went for a set from an Audi as there are more available for that source and I liked the pattern better than most Skoda wheels, Trinity wheels are nice though and I'd have thought you'd get a decent price for them if you sell them, or if you have space keep them and swap over when winter comes.

Thanks fort that GDcobra - very helpful thoughts. I actually went to Kwikfit to address the tyres losing pressure in the interim - and just as chimaera mentioned, it was a corroded value on the front passenger side! They replaced it free of charge so kudos to kwik fit. 

 

Pressures looks stable now so I'm thinking of seeing the current tyres out and taking stock again then. But such helpful thoughts to reference here. Thank you.