Changing from 17 to 18

s3withproblems

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I want to change my alloys to 18" on my S3. And I will be having 225/40/18 tyres. What changes will it make to the car if any? (0-62, handling, top speed, comfort etc.. ) Will a heavier alloy affect the performance ?
 
Bigger alloys will always effect performance and ride as there is more metal to turn and there is less tyre to absorb bumps, unless you go for light weight ones! But you do benefit from improved handling on the S3 with added grip in most conditions, just make you go for a decent set of tyres like Toyo's or Goodyear F1's for the most benefits. Should be little or no effect on your top speed, though you should stick to 70MPH, yes siree /ubbthreads/images/graemlins/beerchug.gif
 
gtr.jpg

Does that alloy (momo gtr) look good on black s3? Is it light or heavy ? Have no idea about alloys
 
jojo,

stupid questionS probably

Why more grip. Unless you are going for wider wheel tyres, wouldn't it be the same.

Is the better handling because lower profile tyres flex less?

Just never really thought about it, and you probably know why. Thanks.
 
[ QUOTE ]
jojo,

stupid questionS probably

Why more grip. Unless you are going for wider wheel tyres, wouldn't it be the same.

Is the better handling because lower profile tyres flex less?

Just never really thought about it, and you probably know why. Thanks.

[/ QUOTE ]

Most probably due to lower profile tyres as you suggested, and gives you more confidence to drive your car more quickly as it all reacts quicker due to less tyre flex. 18" wheels, despite having the same size footprint, will push more of the tyre firmly into the ground during cornering hence more grip?
 
Think of it like this...

The bigger the wheel is, the more rubber is in contact with the road because as the diameter of the wheel increases the curvature decreases, i.e. it flattens out, and hence puts more of it's surface area (in this case rubber) in contact with the road.

It's very minimal, but it is more.

I really don't understand why people say fitting 18" wheels affects the handling. The rolling radius of the wheel is the same (give or take a few mm) due to the lower profile tyre.

It is true that you will feel more of the road etc. due to there being less tyre to absorb the bumps, but the handling, i.e. the way the 'suspension' controls the car and the way it reacts to driving style, will not be affected unless the car is drastically lowered (or raised as is more likely to be the case here). That CAN be the case if, for instance, you go from 14" wheels to 18" wheels as so many of the Nova crew dream of... because the rolling radius is changing by quite a large amount.

But upgrading from 16" to 18" or 17" to 18" (as I have) will mean that as long as the rolling radius of the wheel is unchanged, the 'handling' of the car will be unaffected.

The difference between the rolling radius of a 17" tyre and an 18" tyre to fit the same car with the relevant upgrade in width and profile is usually no more than the difference between a new tyre and a worn tyre. As I said before, a few mm at the very most.

So saying that it completely changes the handling of the car is, in my opinion, a load of rubbish.

T
 
I will have to disagree strongly with your opinion Vaultertrim in that changing the size of your wheels has no effects on handling. you are correct in that when a bigger alloy is used, appropriate tyres are used to keep the rolling radius the same, but to say it has no effect on handling is untrue!
First of all, I'm no expert in handling, it's a science really, and one which takes a life time to master, even the F1 handling experts get it wrong every now and then! - ask Glenn 'EssThree' and he will tell you the same.
In this case, say if the suspension is standard S3 and running on standard 17" 'Avus' wheels, anyone will tell you it's a poor handling hatchback, it just understeers everywhere when pushed hard, and the amount of roll you get when taking corners is another story. Now take the same car and put 18s on it, and it's a lot better, it still understeers, but not as much, so a definite better handling car. This is due the lower profile tyres, which give a quicker response to your steering inputs and also reduces the amount the car rolls(less tyre flex) when pushing hard - It's a small improvement, but it's still a better handling car than when it was wearing 17" wheels. Of course this can be improved on with the addition of lowered suspension, shocks and ARBs , but we're talking about wheels here.
 
I'll do my thick lad impression again then shall I???

ARBs???? help

or should this go somewhere else?

Upgrade route for S3 looks to me like
1. chip to 265 bhp
2. bigger wheels 182 RS4 reps
3. fit bigger brakes to cope with power and 'ring trip
4. better waste gate for more boost
5. FK???? some ARB or other acronym.....
 
[ QUOTE ]
I'll do my thick lad impression again then shall I???

ARBs???? help

or should this go somewhere else?

Upgrade route for S3 looks to me like
1. chip to 265 bhp
2. bigger wheels 182 RS4 reps
3. fit bigger brakes to cope with power and 'ring trip
4. better waste gate for more boost
5. FK???? some ARB or other acronym.....

[/ QUOTE ]

1. Chip is a must on any S3 /ubbthreads/images/graemlins/grin.gif
2. Standard choice of wheel for the standard factory look. /ubbthreads/images/graemlins/cool.gif
3. I would do this before going for the alloys /ubbthreads/images/graemlins/wink.gif
4. I would do this before the remap, to get maximum gains /ubbthreads/images/graemlins/smile.gif
5. ARBs = Anti-Roll Bars dude /ubbthreads/images/graemlins/beerchug.gif
 
Jojo,

I don't I think I worded my last post very well... let me elaborate a little.

What I was getting at was the comments from people who say upgrading to larger wheels makes the handling 'worse'.

I completely agree that it will improve how the car grips etc. due to the reasons you stated above and also due to the fact there is physically more rubber in contact with the road as per my comments in the first paragraph of my previous post.

Sorry for the confusion. My bad!

/ubbthreads/images/graemlins/beerchug.gif

Tim
 

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