I've been running my 1.2 on 16's for a few days and I have found the difference rather shocking. This morning I did a mixture of motorway and town driving (75/25% split), 29MPG average honest to god. I've averaged sub 35MPG and I normally see early 40's on 14" alloys.

The car has creaked and groaned more, is less responsive (I expected as much) so tonight I've stuck my 14" steels back on (tyres on the 14" alloys were getting a bit low). Checked the tyre pressures and went for a blast, the difference was very noticeable.

I'll have to have a long hard think about what I can do wheel wise now!

im guessing the 16s are alot heavier? what profile tyres did you use?

If you have increased the width of the tyre you will have to reduce the profile quite dramatically to maintain the same rolling radius as the 14

Ran/Running 16" vRS alloys on my 1.2 12v no probem. Assume ur using 45 profile tyes?

205/45/16 Tyres.

IMO the result is normal with 205/45/16 Tyres for 1.2!

Yeah, I'd agree, you're increasing the weight and also the rolling resistance which will have an impact on economy and performance, but will allow you to carry more speed through corners.

I think the overall rolling radius is still the same (or as near to the same) as with the originals so the gearing should be the same

Chris

fitting bigger (and wider) wheels often does have an adverse affect on the handling of any car, it's quite often the biggest mistake that modifiers make when they are 'hotting up' thier motor...

i allways tend to choose the smallest wheels possible, so long as the brakes fit inside them of course

So it looks like refurbing the 14's and getting some new rubber for them.

Oh well!

What brand are the 16" wheels? If they're cheap they'll be heavy. Go for a quality brand such as OZ, BBS etc.. and the weight will be much more comparable to the wheels you've removed.

Team Dynamics Monza's apparently built using the materials as the Pro Race series of alloys.

They weigh a lot more than the 14" alloys/steels.

Are the tyres newer on the 16's than on the 14" wheels, i notice a dramatic reduction in MPG when putting new boots on due to the increased grip too.

I noticed this when fitting 17's to my 320i. It killed the performance (not that there was much to start with) and my mpg was even worse than before.

It's unsprung weight that does it. Heavier wheels carry more inertia and are thus harder to turn.

They also tramlined more and caused a harsher ride.

Hard to believe people fitted 19's to those things. You might as well be driving a 2CV in the end it'll be that slow. I wont ever do that again. Big mistake.

The 16's had brand new Goodyear F1's and the 14's were close to needing changing.

I just did a 35 mile run on the M4 @ 65MPH and got 49MPG. Yesterday I was doing a tad more than that but not much more!

And to think you offered to sell them to me

Still, might be up for them - where about do you live?