18's vs 19's performance?

[cheets7]

Evening all!
Putting the looks aside, the Gti will perform better on the 18's over the 19's in most tests? The 19's are purely cosmetic over function?
Just wanted to see people's thoughts on it.

[CraigW]

Is that a question or a statement? Depends how your defining performance. Performance in terms of comfort and handling then probably the 18"s. 

[Jimble]

Don't see many race cars with big wheels and no tyre wall, i reckon it would perform better on 18's but probably not noticably in day to day use.

[matchboy]

Even though I've specced the 19s, the 18s will be quicker for sure. Will it be noticeable? Who knows, but will certainly be quicker.

[Gung-Ho]

It's neither here or there, but they did a similar test on a Nissan 340Z a few years back. The 19"s were only a fraction quicker compared to the 18"'s round the track, but the handling on the 19"s was a lot more unpredictable on the limit.  An inexperienced driver would thus be slowly on the 19"s

http://m.youtube.com/watch?v=o6Glkf4jwkM

[Gnasher]

We had the same scenario with the astra vxr. The general consensus was that the 18s handled more predictably on the limit and had better ride comfort. The difference between the golf and the astra is that the 18" wheels on the astra looked rubbish whereas on the golf they look allright (although I like the looks of the 19s over the 18s on both cars)

[corgi]

It depends on what you mean by performance...

In a straight line (assuming the tyres are the same width) the the one with lighter combination of wheel and tyre should be faster (all other things being equal)...

In other situations, if the road is very smooth, you should, in theory, be able to generate higher cornering forces from a tyre with a lower profile... but you would need to factor in the geometry change (camber/castor/toe) on suspension deflection when cornering...

On a bumpy surface, you may well find the higher profile tyre would be better...

That's all theory, though, you then need to consider the way the car feels on each... and that's very subjective... you might find that two drivers can extract about the same performance out of both setups...

In reality, I think you'd find the difference is too small to measure...