As you decrease the profile for any given width tyre you should increase the rim width it sits on.
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I reckon your fronts wheels are OK but the rears ideally need to be wider by an inch.
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.
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.
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the wheel
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& tyre bible reckons a 7.5" min for a 225/40/17 though as others have stated wider tyres can be run but you probably won't ever hear from those with a bad experience of this since most likely they're not about anymore.
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Tyres are matched to rim sizes for a reason.
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When they're stretched on a wide rim the tyre wall is quite straight and so doesn't deform much under load
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(cornering) which helps steering response but adversely effects comfort.
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On a narrow rim the tyre is pinched which curves the sidewall.
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A curved sidewall will flex more thus exhibiting the opposite characteristics to the straight one.
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.
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.
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.
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Higher fuel consumption too.
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I'd have an absolute max of the 225/40 on the rear and change the front to a 205/40 to keep what I think is the best handling tyre stagger of 20mm.
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If you ever want to space them to make the rears sit as they should in relation to the fronts drop a 12mm spacer on.
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At the moment the facing side of your fronts sit further out than standard
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(about 10mm) whilst the rears sit 2mm further in
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(same 7" width as standard but with a 2mmm higher offset, 47 compared to 45).
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R