Differences between alloys sizes

Sandwich

Looking at a car which can come with 16, 17 or 18" alloys.

What are the practical differences (ie. not cost or aesthetics) between each?

Im guessing:
The bigger the wheel
1) the better the handling
2) the higher the road noise
3) the worse the fuel economy
4) the more the vulnerability to pothole/kerb damage

Or is it more complicated?

TomMc

More or less when tyres are also changed to lower profile ones to have the right rolling circumferance etc.. Less comfort - i.e. poorer ride quality (in most cars) and the more expensive the tyres.

maidhc

Sandwich wrote: »

Or is it more complicated?

All that + a shorter life expectancy for your wheel bearings.

McSandwich

I always thought that smaller wheels gave better handling, especially on corners - the reason ambulances have small wheels.

Also, wouldn't smaller wheels result in more bearing wear as they spin faster? [edit] or maybe thats more tyre wear.. [/edit]

Niall1234

Its the weight of the wheel that is all important. Small gains in making the wheel lighter ads to big gains in handling.

Taking a KG off the weight of each wheel will give far more handling improvement over taking 4KG off the chassis.

Larger wheels give a harder ride as the tyre itself must be small to keep the same wheel circumference.

Sandwich

Thanks for the contributions.

Two further queries:
- Are speedo calibrations ever adjusted for changes in wheel/tyre diameter? Only 1% or 2% difference so Im guessing not.
- Do you get longer tyre life from a 215 than a 205, all else being equal?

Swinging Looney

Don't mean to hijack your thread Sandwich! But just wondering if anyone can tell me what kind of difference in mpg you might expect between a 225 and a 205 tyre?