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Tyre Size

Discussion in 'A3/S3/Sportback (8P Chassis)' started by B111COR, Sep 3, 2010.

  1. B111COR
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    B111COR New Member

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    Used the search but just cant find what I'm looking for:unsure:
    Would I have any issues with a 235/40/18 tyre on 8" rims on a standard set-up Quattro S-Line, I know 225 is the way to go, but I really need some rim protection for the wife :laugh:
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  2. akash_sky1
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    akash_sky1 Active Member

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    Your speedo would become slightly inaccurate, as the rolling radius would be grater, your speedo would under-read slightly more.
    Go on Tire-Rack and it will tell you the percentage change in your speedo accuracy.
    The steering would become a bit more numb as well and there would be slightly more sidewall flex.
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  3. B111COR
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    B111COR New Member

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    Surely the width of the tyre wouldn't affect the speedo? Its 225/40/18 on at the moment on a 7.5" rim
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  4. Ads
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    It won't just be the width of your tyre that increases, it will be the side wall depth also.

    225/40 has a wall depth of 90mm
    235/40 has a wall depth of 94mm
    Last edited: Sep 3, 2010
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  5. B111COR
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    B111COR New Member

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    Ahh, didn't know that, thanks guys, may just stick with the 225's and ban the wife from driving !!
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  6. Ads
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    Yeah, I didn't realise this either at first.
    Basically, changing the width has a knock on effect that changes the whole tyre (diameter and circumference, but not the rim that it fits).

    Why don't you buy some 225/40's which are designed with rim protectors already??
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  7. Scott
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    Scott Well-Known Member

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    My Eagle F1's have a bit of a rim protector
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  8. B111COR
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    B111COR New Member

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    I already have Vredestein Ultrac Sessantas 225/40's, they do have rim protection, but just not enough:crying:
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  9. sub39h
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    sub39h Active Member

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    someone said once that you can code your tyre size in vagcom. so if you do go for a different tyre you can code it to make the speedo accurate. you have to have the same width of tyre on all 4 corners as well cos you have a quattro, and you may get some rubbing but it depends on the make cos they all have different shoulders and some rub and some don't - apparently.
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