Peoples opinions on 18" or 17" alloys ride quality etc etc

[bendhamrait]

Hey guys, second post wooohooo lol

Well whats peoples oppinoions on 17" or 18" alloys does the 18" differ the ride and handling alot compared to 17's ???


ANYPICS PICS OF A3'S WITH 17 OR 18" WHEELS ON STANDARD SUSPENSION WOULD BEE GREATLY APPRECIATED

CHEEEERSSSSSSSSSSSSSSS
:icon_thumright: :icon_thumright: :icon_thumright: :icon_thumright: :icon_thumright: :icon_thumright:

 

[Ess_Three]

18s give a tighter ride...a bit more niggly but much better turn in, less roll on the sidewalls etc..
Much nicer toi push on with 18s on...not much harder than on the 17s but much more direct feeling, changed direction better an quicker, settles quicker...no more outright grip I didn't think, but better confidence.

 

[daveyboy527]

Here is my 2 day old sportback on 18's. Personally, I think it looks the business! Sorry the pics aren't too clear but its all I have at the moment

 

[S3 GAZ]

i'm not sure if it was psychological but when i went form the standard s3 rims to the 18" v6 TT rims i felt the car was slower in every aspect you stated Essthree. it felt heavy, slower off the line, less nimble and not as so pointy and darty to drive, true there wasnt as much roll body wise due to the smaller sidewall but my car just felt like it was wearing shoes that were a size to big.

Perhaps they werent the best wheels to use and i would have been better going for some lightweight BBS or OZ rims. howver i did sell the v6 ones on ebay and i'm back to a set of standard wheels and the car feels better again.

i was wondering if i had had the car remapped with the 18's on if would have given me that sharpness and accelleration back?

 

[Ian W]

I am going to be watching this topic closely, i've had my S3 for a few weeks and after xmas I plan a few mods and general tidy up.

Im stuck with what do with the wheels though, my standard S3 rims need a refurb and a couple of tyres which will cost the best part of £400 or I can get a set of replica 18" RS4's from Awesome GTi with tyres for £500

Replica's also seem to be a bit of talking point, some say there fine, others say there a waste of money ?? Tough decisions !

 

[spannah]

bigger wheels mean bigger tyres therefore more traction, the weight of the wheels do make a difference therefore they will definatly slow the car down as if u got 4 anchors on your car. Handeling wise would be great tho.

 

[rodenal]

With an S3 i'd say a set of 18's would be fine - the original poster has a 1.6 tho.

On mine the car felt very heavy and unwilling to turn in, although very stable at the same time. With the smaller wheels it now has it now feels much more agile both in terms of getting off the line and on the twisty stuff.

 

[Ess_Three]

i'm not sure if it was psychological but when i went form the standard s3 rims to the 18" v6 TT rims i felt the car was slower in every aspect you stated Essthree. it felt heavy, slower off the line, less nimble and not as so pointy and darty to drive, true there wasnt as much roll body wise due to the smaller sidewall but my car just felt like it was wearing shoes that were a size to big.

Perhaps they werent the best wheels to use and i would have been better going for some lightweight BBS or OZ rims. howver i did sell the v6 ones on ebay and i'm back to a set of standard wheels and the car feels better again.

I had a set of BBS 18s that were slightly lighter than the standard S3 17s.
Comparing back to back gave those results...

But, heavier wheels will do the opposite...slow the car down off the line, make it harder to get turned in, less nimble etc...
If the total weight of wheels and tyres is heavier, then you will get the results you stated.

Perhaps I should have said that...I'm always looking to sit stronger and lighter wheels for that reason.

also, the further the suspension has been taken (better dampers, springs, ARBs etc) the more obvious the difference in feel and confidence between 17s and 18s.

i was wondering if i had had the car remapped with the 18's on if would have given me that sharpness and accelleration back?

You'll get better performance...but you'll still be fighting heavy wheels.
No way round that, i'm afraid...except to fit light wheels!

 

[S3 GAZ]

I had a set of BBS 18s that were slightly lighter than the standard S3 17s.
Comparing back to back gave those results...

But, heavier wheels will do the opposite...slow the car down off the line, make it harder to get turned in, less nimble etc...
If the total weight of wheels and tyres is heavier, then you will get the results you stated.

Perhaps I should have said that...I'm always looking to sit stronger and lighter wheels for that reason.

Yeh sounds about right mate cant dodge the laws of physics i suppose. I'm gonna save my pennies and get some lightweight wheels.

cheers
gaz

 

[Carpy25]

don't know if there is a ride hight diff between 1.6 as you have or 1.8 se photo below , just about gets away without lowering i think but mine is a daily driver

tt alloys 17" by 7 or 7.5 no sure fitted with 225 45 17 tyres






Rob

 

[Teejay]

bigger wheels mean bigger tyres therefore more traction, the weight of the wheels do make a difference therefore they will definatly slow the car down as if u got 4 anchors on your car. Handeling wise would be great tho.

sorry, but that's poop.

bigger wheels means smaller tyres, so that you keep the rolling radius the same and hence the speedo accurate. The car will handle better because there is less give in the smaller tyre walls, but there is no more rubber in contact with the floor and definitely no more traction.

and in any case the force applied by the car on the road (traction) is directly proportional to the weight of the car. more rubber in contact with the floor means less force per square cm of rubber. F=MA and since The Mass of the car isn't changing and acceleration is Gravity (again not changing) the amount of frictional grip cannot be increased.

the only way to increase grip is to go for a different compound rubber and then you're into chemical grip, but I'm not gonna get into that because it's complicated.

bigger wheels generally mean more metal and will be heavier which increases your rolling weight, which increases inertia, which means you lose some of your power during acceleration. top speed will not be affected.

I'm done now

 

[Ess_Three]

sorry, but that's poop.

bigger wheels means smaller tyres, so that you keep the rolling radius the same and hence the speedo accurate. The car will handle better because there is less give in the smaller tyre walls, but there is no more rubber in contact with the floor and definitely no more traction.

Sorry...but your retort is equally poop.

It's the terms 'bigger' and 'smaller' that can cause confusion.

Bigger wheels do not mean 'smaller' tyres as the tyre's width is the commonly accepted measurement of size 205, 225, 295 etc.
Bigger wheels mean smaller sidewalls as you were intimating...but not always smaller (width) tyres...
Which means the original poster was correct in their comment that larger wheels generally means larger (wider) tyres...for example going from a 195/55 tyre on a 6" wide 15" wheel up to 18" wheels will mean going up to a 7.5" or 8.0" wheel as you don't get too many 6.5" wide 18" wheels...so you'll need to fit a 215 or 225 tyre to keep things safe.
Hence, bigger tyres...width wise anyway.

and in any case the force applied by the car on the road (traction) is directly proportional to the weight of the car. more rubber in contact with the floor means less force per square cm of rubber. F=MA and since The Mass of the car isn't changing and acceleration is Gravity (again not changing) the amount of frictional grip cannot be increased.

the only way to increase grip is to go for a different compound rubber and then you're into chemical grip, but I'm not gonna get into that because it's complicated.

Again, point out that whilst you ar correct in what you say, the original post referred to bigger (the assumption being 'wider') tyres giving more traction, which they do.
OK...in the wet wide tyres can be worse depending on pressures and comploud, but in general terms, wider tyres = better traction and more grip.

bigger wheels generally mean more metal and will be heavier which increases your rolling weight, which increases inertia, which means you lose some of your power during acceleration. top speed will not be affected.

All true...
Except larger (wider) wheels will cause more drag (aerodynamic drag, bigger frontal area) and more frictional drag (more rubber in contact with the road), both of which WILL affect the top speed in a negative way.

I'm done now

So am I!

 

[Teejay]

Sorry...but your retort is equally poop.

It's the terms 'bigger' and 'smaller' that can cause confusion.

Bigger wheels do not mean 'smaller' tyres as the tyre's width is the commonly accepted measurement of size 205, 225, 295 etc.
Bigger wheels mean smaller sidewalls as you were intimating...but not always smaller (width) tyres...
Which means the original poster was correct in their comment that larger wheels generally means larger (wider) tyres...for example going from a 195/55 tyre on a 6" wide 15" wheel up to 18" wheels will mean going up to a 7.5" or 8.0" wheel as you don't get too many 6.5" wide 18" wheels...so you'll need to fit a 215 or 225 tyre to keep things safe.
Hence, bigger tyres...width wise anyway.

I'll let you have that one. The assumption on bigger diameter was wrong.

Again, point out that whilst you ar correct in what you say, the original post referred to bigger (the assumption being 'wider') tyres giving more traction, which they do.
OK...in the wet wide tyres can be worse depending on pressures and comploud, but in general terms, wider tyres = better traction and more grip.

wider tyres cannot provide more grip for the same weight car. The improvement in cornering ability is because you have a bigger wheel which means you have a smaller sidewall. the wider tyre is just an aesthetic bonus and in the long run does provide vehicle stability.

All true...
Except larger (wider) wheels will cause more drag (aerodynamic drag, bigger frontal area) and more frictional drag (more rubber in contact with the road), both of which WILL affect the top speed in a negative way.

aerodynamic drag on a tyre - negligible, but ok if you're being picky. I think the pretty much flat front of an audi would negate this anyway.

frictional drag - no more than on the narrower tyre. This comes back to the F=MA yes there is more rubber in contact with the road, but the force exerted by any part of it is smaller. For the same rubber compound it would be the same.



So to answer the original question, yes the ride will be harsher - but not too harsh on 18's, you'd need to go to 19's to suffer.
The handling improvement would depend on the width of tyre/profile you ellected for:
225/40R18 has a sidewall of 90mm
215/45R17 has a sidewall of 96mm
215/40R18 has a sidewall of 86mm (and gives a nice euro-stretched look).

however the smaller sidewall handling differences can easily be cancelled out by poor choice of tyres, worn suspension etc. Or alternatively more benefit could be gained from uprated suspension and great tyre choice.

At the end of the day on a road car that's driven every day it's about looks over tiny performance details, as the minute performance advantages you'd pick up from some tweaks will not be noticeable in every day driving.

 

[Ess_Three]

wider tyres cannot provide more grip for the same weight car. The improvement in cornering ability is because you have a bigger wheel which means you have a smaller sidewall. the wider tyre is just an aesthetic bonus and in the long run does provide vehicle stability.

No...
Better cornering is by virtue of the fact that you have more rubber in contact with the road, which gives more grip.
Simple.

185 vs 225..you have more rubber on the road with 225s...so more traction and can excert more lateral force whilst cornering...more grip.

The turn in and confidence is a function of sidewall aspect ratio...

aerodynamic drag on a tyre - negligible, but ok if you're being picky. I think the pretty much flat front of an audi would negate this anyway.

Flat front?
CD of 0.3 ish?
Flat?
That's not flat in anyones book.

And wide tyres add to both the drag coefficient and the frictional losses when you get well over 100MPH...at the S3s top speed of 150 they add quite a noticable amount.

frictional drag - no more than on the narrower tyre. This comes back to the F=MA yes there is more rubber in contact with the road, but the force exerted by any part of it is smaller. For the same rubber compound it would be the same.

Of course the frictional losses are higher..go and measure them on a rolling road...swap between 185s and 225s and look at the losses...Ok they aren't truly representative because of the two rollers...but you'll get the idea.

Also, try using a rolling road and sticking an additional 10 psi in each tyre...less losses.
Same tyre...how does your theory work that out?

It's all about the tyres footprint on the road....the larger the footprint, the better the grip (within reason...and compound, tyre pressures, road conditions accepted)

More rubber on the road = more traction = more grip = more friction.

At the end of the day on a road car that's driven every day it's about looks over tiny performance details, as the minute performance advantages you'd pick up from some tweaks will not be noticeable in every day driving.

Sorry, I don't agree...
Looks over performance...stick to reading PVW or similar...I can spot differences in tyres width, size etc...and I'm damn sure others can....so they aren't that 'minute'.

 

[bendhamrait]

Cheeers everyone , i didnt mean o start such a technical debate, reminds me of being at college lol, but i aprreciate all the help!

it was only a general question as i am debating what wheels to purchse lol, well what size, i only have a 1.6 so wont be going near 150MPH lol


i think 17's are the correct choic for me as i dnt want the car to feel anymore slugish as it is hardly quick at the moment lol, and i like the nimbleness :S of my car at the moment and by the sounds of it 18's will not hav a good effect in my opinion.

cheers guys dnt suppose any1 is from hull on here lol? i am

 

[carbster09]

I just read the tyre test in EVO, which used New Golf GTI's. Since its a similar car power wise to my S3, I read with great interest. The new Goodyear F1 Assymmtric did very good. HOWEVER .... tye used 17's wheels for the testing. Then at one point they mounted a set of tyres on the 18"ers and did a few laps. The 17" wheel set up was 2.5 sec faster .... very interesting indeed. I know that there are many factors, but it comes close to confirming the big wheel, heavy wheel will loose out on a tight track.

cc