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The 18s v 19s debate...

Discussion in 'A3/S3/Sportback (8P Chassis)' started by elrao, Apr 30, 2013.

  1. elrao
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    elrao Member

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    [Apr 30, 2013]
    I full accept that the ride will be worse on 19s with a 235/35/19 tyre than a 225/40/18 due to the lower profile.

    What I'm trying to understand is why people also report that handling 'is ruined' on 19s?

    I would have thought there were a number of reasons why a move to 19s should have improved handling:

    Good quality aftermarket 19" wheel will weigh less than an OEM Audi 18" = less unsprung weight

    An 8.5Jx19 ET45 rim will give an overall wider stance than a standard wheel (without spacers)

    A 235/35 has more rubber on the ground than a 225/40 - more grip (unless its snowing!)

    235/35 has about 9% less height than a 225/40 - less roll in the tyre when cornering

    However I'm told this is not the case and these factors combine to give a worse handling car?

    Can anyone explain to me why?
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  3. S3Alex
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    S3Alex Rarely neutral

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    [Apr 30, 2013]
    I guess the likely reason is reduced overall suspension compliance due to the reduction in tyre section,but aside from that,I don't really know.

    As you know,I took a different route,and after a lot of work,got 245x40x18 tyres on 18x9 rims fitted,and the extra track and camber give hugely better handling.

    Someone far better than me will come along soon enough and explain it,I'm sure!
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  4. elrao
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    elrao Member

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    [Apr 30, 2013]
    Yeah, you have wider tyres and wider track = better grip.

    Has to be related to the lower profile tyre and how this impacts the stock suspension set-up.

    90mm profile seems to be favoured by Audi, (225/40 on an 18 and 255/35 on a 19)
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  5. Boydie
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    Boydie Boycie VCDS Map User

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    [Apr 30, 2013]
    19" BBS CH 235/35/19 P Zero on my daily S3 and have been for the last 3.5 years. The ride is harsh but that is due to upgraded suspension and arbs.

    Handles amazingly, looks awesome, wouldn't want it any other way :)
    #4
  6. S3Alex
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    S3Alex Rarely neutral

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    [Apr 30, 2013]
    Dont think I'll ever be done fiddling with the setup!

    The 245x40 Supersports are slightly more rounded on the shoulder than the R888's so I've found they don't rub which means I can lower the car a little,and also change the bump/rebound rates...and so it goes on!
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  7. coreythorny
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    coreythorny Member

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    [Apr 30, 2013]
    It's completely down the sidewalls.
    Yes to a degree, lower sidewalls, less roll etc. but think about it, why don't formula one cars ride on walls of 4cm like the 19s? ;)
    theres a point where the lower the sidewall the worse the handling starts to become, some flex is desired for handling. It's a trial and error thing, I don't know of any formulas to work it out as of yet.
    Also ride will be worse due to less flex as you know.
    Also people relate aftermarket 19s being worse than aftermarket 18s. Overall 18s against 19s in the same make, the 18s will weigh less in total with tyres then 19s with tyres.
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  8. Mr. B
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    Mr. B English...not so good

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    [Apr 30, 2013]
    I think all you can really say is "different handling". Bigger wheels will improve some aspects of handling and worsen others
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  9. Burkin
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    Burkin Member

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    [Apr 30, 2013]
    I have 19" on 215 tyres and coilovers set pretty firm and although ride is rough the handling is really good, much better than it was standard and the grip is fab but that's probably down to good tyres as well. Unless your in the Le Mans 24hr I don't see and handling issues mattering
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  10. S3Alex
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    S3Alex Rarely neutral

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    [Apr 30, 2013]
    One of the major parts of compliance and suspension movement in an F1 car is the sidewall of the tyre.
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  11. elrao
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    elrao Member

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    [Apr 30, 2013]
    It's so Perez can bump Button without killing the pair of them.
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