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gt tyres

hi guys has anyone fitted 235/40/17 tyres to the rear of their GT, what are the pros and cons,i have two tyres of this size and two spare standard alloys
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205-55R16 vs 225-45R17 vs 235-40R17 - Tire and Wheel Plus Sizing | Tire Size Calculator

Circumference is 1.9% smaller, so your speedo will read 1.9% higher for the same GPS speed.

As long as you keep the same size and tread pattern on each axle it will not bother too much... I've run staggered wheels (wider rear than front) on my 156 without ABS swearing at me.

If you put a space saver wheel on the difference is too much for the ABS to handle and will throw ABS / stability warnings
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205-55R16 vs 225-45R17 vs 235-40R17 - Tire and Wheel Plus Sizing | Tire Size Calculator

Circumference is 1.9% smaller, so your speedo will read 1.9% higher for the same GPS speed.

As long as you keep the same size and tread pattern on each axle it will not bother too much... I've run staggered wheels (wider rear than front) on my 156 without ABS swearing at me.

If you put a space saver wheel on the difference is too much for the ABS to handle and will throw ABS / stability warnings
they would be on the rear so wont affect the speedo
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Smaller overall diameter on rears would affect the stance.

Wider tread may??? catch the suspension (the 225s are pretty close anyway).

Lower profile would "harden" the ride.

All of which I'm sure you've considered. But would these "negatives" be all that noticeable in the "real world"?

But you would increase grip at the rear and lower it for flatter handling. Again how noticeable would that actually be?

Because you have the wheels and tyres available, trying it out would only have minimal cost and would be very easy to reverse if it proved troublesome. If it were me I'd give it a go. Unless someone has actually tried this out and knows of a good reason not to.
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Plus it is a bit silly putting wider rear tyres onto a Front Wheel Drive car.
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But you would increase grip at the rear and lower it for flatter handling. Again how noticeable would that actually be?
You wouldn't be increasing the grip by fitting wider tyres to a standard car.

Grip is a function of the weight (mass of car + any downforce) and the coefficient of friction between the rubber and road. Having wider tyres just means there's more rubber to spread that weight over so that you don't over-heat the rubber compound and lose traction that way, and/or so you don't use up the tread too quickly by working a narrower tread block.
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Quote:
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You wouldn't be increasing the grip by fitting wider tyres to a standard car.
The question is not about increased grip, but cool for pointing it out to others reading the thread.

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Originally Posted by jonb.gt View Post
Smaller overall diameter on rears would affect the stance.
1.9% diameter difference will hardly show up on anything bar a perfectly flat garage floor. 10mm wider tire (i.e 5mm left and 5mm right) will also not be visible really

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Originally Posted by jonb.gt View Post
Wider tread may??? catch the suspension (the 225s are pretty close anyway).

Because you have the wheels and tyres available, trying it out would only have minimal cost and would be very easy to reverse if it proved troublesome. If it were me I'd give it a go. Unless someone has actually tried this out and knows of a good reason not to.
This is it - You have them available - yes use them. I have had a set of 235's at the rear with the suspension significantly lowered, then yes then they rub from time to time. I lifted the suspension by 2cm (still lower than OEM) again and no more rubbing.
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The question is not about increased grip, but cool for pointing it out to others reading the thread.


1.9% diameter difference will hardly show up on anything bar a perfectly flat garage floor. 10mm wider tire (i.e 5mm left and 5mm right) will also not be visible really


This is it - You have them available - yes use them. I have had a set of 235's at the rear with the suspension significantly lowered, then yes then they rub from time to time. I lifted the suspension by 2cm (still lower than OEM) again and no more rubbing.
cheers guys , the width is whats making me think, ive got 215 45s at the moment, my rear shock collapsed yesterday and the spring support destroyed the rear tyre, its only that i have them sitting in my shed that i thought about it, having no job at the moment and having just moved back into my house after living on a canal boat for the last 18 months
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