225/40/18 question

[Secla]

Looking at tyres and camskill have an offer on vredstein vortis at the moment which seem to get good reviews

£76 a corner for 225/45 but only £48 in 225/40

its not a daily driver so the lower profile doesnt really bother me but im sure i read something about the possibility of upsetting stability control etc. or is this just if you run different profiles front/rear ?

[plas87]

Can you please post a link? Cheapest I saw was £62 a corner

[Secla]

There on cam skill with £15 a corner cash back
63.45 I think then claim back

[Scartlead]

If you're running 45's or the same profile all round then you'll be fine. Try not to skimp too much in tyres as our 8's like the good stuff

[Secla]

Yeh I wasn’t looking at cheap rubbish but if I can save £100 on tyres and the only downside is a slightly firmer ride then I’d be happy

[plas87]

The 225 40 R18 tyres a bit lighter than the OEM size, so should provide quicker acceleration (albeit insignificant). There will also be a slightly bigger gap in the wheel arches too

[PeteH]

It will have reduced load capacity, reduced cornering stiffness, less grip, will reduce your gearing, increase your fuel consumption, and if your insurance company find out you have fitted the wrong size then you might find you are uninsured. You will also have worse ride, and your rims will be more vulnerable to damage. And you will need to inflate to a higher pressure.

All of these effects will be small, and the risk of your insurance company finding out is also small, but they all add up to make the tyre slightly less suitable for the RX-8. I know you think you are saving a few quid, but just trust Mazda. They specified the size for good reason, and they didn't elect to fit a tyre that was deliberately more expensive than it needed to be. In fact you may be sure that the "bean counters" at Mazda tried hard to get the cost of the tyres down, but the engineers will have argued hard for the right tyre.

Every small change that is done to "dilute" a car eventually adds up to making the car feel worse. For me that's always a shame.

If you want a coupe with tiny tyres and no grip, you can always buy a GT86.

[casey]

If you want a coupe with tiny tyres and no grip, you can always buy a GT86.

Cue Nigel........

[plas87]

The other reccomendation is 235 40 r18, which will also work against you if the insurers ever find out

[warpc0il]

235/40R18 was a factory option, so shouldn't cause the problems described or issues with insurers, as long as you choose a good brand with the correct load/speed rating.

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