How wide tires affect overall performance

Apoc370z

Just a quick question here.

I will be mounting my new GS4 soon after my OEM tires wear out, 22k miles and still have maybe 30% left.

thinking about going with Bridgestone Potenza RE-11 with 265/35 front and 305/30 on the rear.

The GS4 will already be adding weight (comparing to the stock 18") so i am not sure how the wide tire specs will affect the overall performance. anyone have any ideas?

the Z is my dd and i do not track it, for now anyways. But i do take a canyon road to work so there are a lot of corners and curves.

any other recommendations will be greatly appreciated.

Zoren 370

Certainly it would improve the handling with the 305's on the rear. The principle behind that is the more/wider contact with road makes you more stable on the curve. I do recommend have your camber at -2 at the rear.
It does make your tire wear uneven though but it is what it is...you could not get both worlds in life either.

The down side you sacrifice acceleration as you spin a heavier mass with the 305.

I don't care as you said you don't race the car in the track and dd it on the mountains the 305 is just perfect! I love mine!

Chuck33079

MAybe you sacrifice acceleration, maybe not. If you can apply more throttle without spinning the tires, you're going to accelerate faster.

Wider tires will improve your handling in the dry. In rain or snow, it will hurt handling. A 305 may be overkill unless you're putting down serious power.

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raymondo510

[QUOTE=Chuck33079;2503801] In rain or snow, it will hurt handling. QUOTE]

Could you maybe elaborate on that, im just curious as to how it hurts your handling.

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JARblue

With snow tires you want a smaller footprint because that means the tires have to displace less snow. Hence, snow tires are typically quite narrow. A wide tire with a larger footprint has more to displace, which means the more snow, the more likely you are to loose traction.

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Chuck33079

The same applies to standing water. A wider tire is more likely to hydroplane.

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wheee!

I love my setup: 275 front and 305 rear. Track day was amazing and DD is great too. I run -1.2 rear camber though for better tire wear and performance has not suffered at all.

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osbornsm

Generally Speaking OP:

TOO wide front tire = More Understeer
TOO wide rear = no such thing

*Note: There is such thing as having a tire too wide for the wheel also

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Chuck33079

Sure there is. It's a tradeoff between width and tire weight and rolling resistance. And your front/rear explanation just describes putting a wider tire on one end of the car. If you go wider on both front and rear in the same amount, there will be very little change in the car's balance between understeer and oversteer.

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osbornsm

And now i learned something

Innnnnteresting...

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kenchan

if you're just streeting the car, just use stock size. maybe go 285/35/19 on the rear which is nismo size.

otherwise it's really overkill imho and just weights down the car.

quality stock size tires > cheap wide tires

DEpointfive0

Hey, hey!!! First of all

I'm ordering my 305's today!



I want 305's because they look SEXXXY
Apples to apples, the Michelin PSS weighs 27lbs as a 275, 28lbs for a 285, and 30 lbs for a 305. Those are some of the lightest tires you can find.

RE-11's are 31lbs for the 285 and 32lbs for the 305's

So not a WHOLE hell of a lot depending on which compound you want to stick to (no pun intended) and the tires get lighter over time! Lol
Lastly, 305/30-19's are 1.3% shorter than 275/35's so the added weight might mean a hair less because now you've geared up the car

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Chuck33079

This is a good enough reason.

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wheee!

whut?

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FortuneLSX-TT

As Chuck pointed out it is not as simple as all that. For example, for the stock Nismo sizes at 245 front and 285 rear there is a 40mm stagger. This results in the car driving like a plow under certain conditions (understeer). If you keep the rear the same size and put a wider front tire compared to stock on the front, it will not increase understeer. It will actually bring the car closer to neutral and reduce understeer. The larger front tire creates more grip allowing the car to turn instead of going straight while you're turning.

Conversely, if you simply increased the rear size and left the front alone you would be increasing understeer.

Personally, I went to a 285 front and 305 rear combination. I still have mild understeer that can easily switch to power oversteer. I do plan on going to a 305 square setup to get to neutral and so I can rotate my tires.

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