Whats the correct pressure for 18" just got a new set of wheels and tyres and noticed a drop of about 4 MPG chances are its tyres are incorrectly inflated.

But i cant find a definative answer. The tyres are Endruo Sports

I've always had a economy drop in the past with wheels size increases.

I always put it down to the extra weight.

Last time i had 18s (on an Audi A4, so similar size/wieght), i ran them at ~30PSI.

If you're running a standardish width (205 to 225 section), I'd stick to standardish pressures.

As Snail says, the extra weight could be a factor. If the 18" rim and tyre weighs 1kg more than a 17" combo, that's equivalent to hauling an 85kg bloke around when you're doing 60 (because effective reciprocating mass rises as the 4th power of speed)! :eek:

yeah i weighed the alloys and too my suprise they were 3kg per wheel heavier. But when u consider its only 2 stone didnt think it would make any difference really not even the weight of your average dog.

but its may have something to do with that reciprocating mass factor thingie you were on about will have a fiddle with the tyre pressures and see how it goes, im not tight but its hardly an economical car so i wanna squeeze as many mile out the tank as possible

thanks again.

Oh P.S Anyone have any advice on dump valves thinking of getting one, any advice on what make type etccc.

cheers

Awesome GTi are just down the road from you, and will be able to supply (and fit if necessary) something suitable.

Been running 18`s for a few years on mine, tend to inflate them to 32psi which gives me good even wear across the tyre...but then i do use nitrogen (Uniflate)

Phil

tried them and they were a bit under inflated got them to 32psi all round and im back up to 31mpg to work which is only 8miles away and mostly traffic so im happy.

Thanks for all the advice