Hi there, apologies for the barrage of posts, just getting used to my new fabia, hopefully will be able to contribute back once I work my way around the car!

I currently have the standard steel wheel, but I'm thinking about getting hold of a set of the Skoda alloys. Im looking at various types, styles and sizes but naturally all bigger than the steelys. Question is what will be the implications on my MPG? I assume bigger wheels = worse MPG but will the effect be that bad if I'm using OEM wheels, obviously they are designed for the car but will the still negatively effect my fuel use?!

Bigger wheels with a bigger rolling diameter will raise your gearing and give better mpg not worse.

It does depend on what tyre size you use on the bigger wheels as low profiles could give a similar rolling diameter to your steel wheels.

Okay so higher gearing won't mean the engine has to work harder?

Don't forget weight will play a big part in MPG and in performance too (both speed and handling, although how noticeable I don't know). Heavier they are, worse all of those things will be. Although if they're wider, then you should get more grip/resistance, which will help handling, but the extra resistance will bring MPG down a bit.

That said, I don't think there's much of a difference between my BBS's/BBS'/BBSs' (where does the ' go?!) and the steel wheels I use over winter in terms of weight. . . Should of weighed them when I swapped them yesterday really!

For gearing - ideally it'll stay the same, otherwise the speedo will be out. You'd keep it the same by using a lower profile tyre as the rim size increases, if that makes sense?

Edited 12 March, 201214 yr by TriggerFish

Yeah makes sense. I ran my felicia on 15" wheel which were much wider than the standard and the mpg difference was massive but I was just interested if the factory wheels would be better (ie skoda worked out what sizes didn't make a difference and used them!

Assuming you use the right tyres to maintain the same rolling diameter - and why not - then the marginal increase in fuel usage from the wider footprint (= higher rolling resistance) might be just a small fraction compared to the increase in insurance premium...