So I'm looking to buy some new tires for my stock 17x8 Rims on my VIII. Is there much of a difference/which would you get if you were to choose from 235/40/17 or 235/45/17. Thanks.

 

The 40s are a bit short. Many use a 245/40-17 if you want to run 40's.

 

Or 255/47/17

 

the 245/40r17 is about as wide as you might wanna go under stock fenders its a shorter sidewall but you get a slightly wider tires...obviously. But it all depends on if you want your speedometer to be off or not. But the 245/40R17 is about the limit you want for your rim size and fender space. especially if you have springs that drop your car and inch or so

 

235/45
245/45 (depending on tire - some rub)
245/40
255/40

All fit. Each as their own application.

Search and read. One of these most commonly asked questions.

 

Nobody is going to like this idea but it works. If you are going for handling and not for looks then 225/45-17. A tire this size has sidewalls the slope inward from the rim. It is like having more negative camber. It may be the correct size for the Evo with stock rims.

 

Only times most run the 225s are on snowies in the winter. Skinnier tire def better in snow and muck in my expierience. Im def Not a tire guru though

 

Wut?

In terms of ultimate grip, wider is better for tarmac. Snow - thinner. Turn in response, shorter sidewall/stiffer sidewall.

 

Wut? - I like that.

I don't know about ultimate grip - no way to test that, but I am running around Goodyear Eagle GT HR's in the 225x45-17 size and they are handling upgrade over the Potenza RE01R's I just pulled off. These Goodyears have a tread wear rating of 440!

BTW, did you see Myth Busters the other night where they made a dimpled car like a golf ball and got better gas mileage. You never know until you try it.

 

^I think Smike is referring to 255 vs your 225. When you went from RE01Rs, were they also 225? If so, that isn't the width having an effect on hadling upgrade, that is the comp/tread.

BTW - when you say handling upgrade do you mean rides nicer or grips better?

 

255 to 225 is a 1.2in difference. No way they will have more grip, with compounds being the same. And yes, that is testable - skid pad.

And REO1Rs are most definitely stickier than Eagle GTs. And I am running the Eagle GTs on my SVTF.

Tires degrade over time. Heat cycling and wear decrease grip. So you might feel they are better, but thats because they are newer.

That being said, I have AX'd the crap out of my Eagle GTs this year. Wet and dry. Actually did quiet well. But I lost 2s to similar cars on Z1*s.

 

Well, I'm not going to be going to a skid pad. I'm pretty sure the RE01R's would win there.

What I found was lack of road wander, improved steering precision and much better turn-in, qualities valued on the street. I got spoiled by the stockers but these tires come pretty close in the turn-in department.

Maybe I am wrong in attributing the difference to the stand up sidewalls and Goodyear just decided to make a really good tire. Tire Rack didn't have much good to say about them.

As for the REO1R's, they went on last spring in stock size. I made the mistake of shooting off my mouth about how it did my own alignment back then and the tire shop people remembered. So, when the tires were being dismounted there were also two managers out there. It looked like a football huddle as they examined the tread wear. Well, they concluded I knew what I was doing. The stones still look like new.

All else I can tell you is that I am having a blast on these new tires.

 

The Evo loves to track ruts. Going to a wider tire can make the sensation worse. A wider tire will also decrease turn in response. Ultimate grip is the amount of available grip at maximum lateral load (breakaway - 255s should be able to take more...also compound dependent).

The Eagle GTs have a very stiff sidewall. I have a XL load version on my car. So even stiffer. I like them more than the GY F1 All-Season I ran on my Evo.

 

This a little off of the subject but since this thread is titled "Opinions" here goes.

I am old enough to have run some of the first radial tires marketed in the USA. After bias tires radials were a revolution in ride and handling.

A radial tire has most of its cords under the tread instead of having the same amount everywhere as in a bias tire. This make for thin sidewalls that dissipate heat. It also made the sidewalls flexible which caused the tires to look low on air when inflated to the proper pressure.

Now along comes radials with stiff sidewalls. Well, there are two ways of keeping a tire cool at high speeds: make the sidewalls thin enough to dissipate the heat or make the sidewalls so stiff they don't flex and therefore don't generate heat. Stiff sidewalls have the added benefit of better turn-in.

Go to a tire store and browse and you find most tires of the thin flexible sidewall type. I suggest these soon will be gone as all tires go to the stiff sidewall type. The next revolution in tires is now occurring.

 

There is a lot of engineering that is goes into tires. Not everyone is going to want a stiff sidewall. The internal carcass depends on components use. We are seeing new kevlar/carbon fiber carcasses. Lots of cool things happening.