Can i get an 18inch steel from anywhere? I dont have a spare but i have an 18inch spare tyre if not could you use any wheel from any octavia as a spare or does it have to be the same size?

I would think it's the overall diameter of the wheel and tyre that matters, not the size of the wheel itself. An 18inch wheel will have a very low profile tyre, a smaller wheel a less low profile. Others will doubtless be along with details. Is your spare tyre the same size as the four on the car?

For a legal unrestricted spare the sizes and type of tyre need to be the exactly same. I can find no legislation regarding the wheel that the tyre is on, though.

 

I don't think they do an 18" steel, but you should be able to get lots of alloys on ebay.

i seached and couln't find a 5x112 18" steel with the right offset. 

You want a deeper 16" steel wheel. It'll be 195/60 or something like that, have a dig around the site for details on winter tyres, most of the guys with them have used 16" steels.

 

As mentioned the outer diameter stays the same.

The standard Skoda supplied spare to use with 225/40-18 tyres is a 205/55-16 as supplied with my car.

 

Alternatively purchase a cheap alloy 7.5x18 wheel with ET around 51 and fit your 18" (225/40?) spare tyre.

Try the Octavia MkIII forum.

 

The MkIII vRS is available with either 17" or 18" steel spares.

 

17" is the minimum to fit over the brake calipers.