Could use help with a rather odd issue

hermit

This is true. However, going wider sounds good since I'll be FI. And, I want to make sure my wheels are protected.


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MacCool

As to protecting the wheels, my S-04s protect the rims very well. I'll try to get a picture later to demonstrate.

Friction (traction, in this case) isn't dependent on contact area between tire and asphalt/concrete. It's only dependent on weight of the vehicle and the coefficient of friction (in this case, the nature of the tire compound). Given the same rubber compound, wider tires don't get you better traction. They CAN/DO create or solve sidewall problems. A wider contact patch can allow a softer tire compound such that the sidewalls can support the weight, but wider tire does adversely affect tire wear, as does the necessarily softer compound.

Mind-blower, huh? Look it up. Many people are resistant to the concept that big wide tires don't give better traction, but it's a well-understood concept in physics. I remember the old sandpaper block experiments from high school physics my junior year. I've taken a lot of physics courses since then...neither the concept nor the formula have changed. The formula for friction is:

Fr = μN

where:

Fr is the resistive force of friction (traction)
μ is the coefficient of friction for the two surfaces (nature of the tire compound)
N is the perpendicular force pushing the two objects together (weight of vehicle)

Note that surface area of the contact patch between the two surfaces plays no role in figuring resistive force (friction/traction). If you prize sidewall stiffness as an aid to cornering then you'll actually want narrower tires. Narrower tires allow stiffer sidewalls if the tire compound is the same, as I believe it is in all of these summer performance tires across a given line.



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hermit

Well, that's some great information there. Thanks for taking the time to type it. I didn't know any of that, so it's appreciated. Indeed, I would like to see pics of your S-04 protecting the wheel. Just so I can see how it looks. Thanks.


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Spooler

Wider tires dissipate the heat better. So it takes them longer to get greasy if heat is causing the issue. If I were you I would go with the 285/35/19 on front and 325/30/19 on the rear RE-11 setup. I have on my car right now 265/35/19 front and 285/25/19 rear SO-4's. The SO-4's do not offer anything wider than 305/30/19's. I will be going wider when these tires wear out. I do not like the stretched look at all. There is a thread on here with the Nismo wheels and wider tires I speak of.


Link to thread.
Why you should use these tires with NISMO Wheels: 285/35R19 (F), 325/30R19 (R)

hermit

Awesome information, thank you for that. As soon as I am finished with some work I'll check out this thread. I'm quite interested, I'll post back in a bit.

kenchan

k, so we need to get bicycle tires now.

JC-Nismo

Thats looks like car wash or Bank of America drive trough damage.

MacCool

Nah. Tire-buying is all about looks.

hermit

You know, I think I came across a discussion about this on some thread a long time ago. Some people were saying that more width = more tread on ground = more traction. While others were opposing that idea. I know a very small portion of the tire actually touches the ground. And I thought the only way to increase that amount was through width. Though it may be just a small addition.

I didn't know that wider tires dissipate heat better. If nothing else, that alone is worth going wider. Aside from a better more aggressive look, in my opinion.

But taking it to a simple extreme, just a thought. So, say I take tires the width most Prius's use but a high performance tire like the RE-11. Then I take the Nismo's stock tire size in the RE-11. Let's just say both 19" and compare on same exact 370Z. I would think all I would do with the prius size is spin all day. It's a confusing concept to think other-wise. However, I am an opened mind and like to learn.

MacCool

True. And they resist shredding better since the friction is spread over a wider area. It could be really important if the OP is going to track the car and really plans on putting major league cornering stresses on those tires. Daily driving on the street, even "spirited" daily driving on the street, no way are OEM-size tires going to have heat or shredding dissipation problems.

But those big ol' wide tires will sure look cool. Just like a real racing car .

hermit

I'm thinking car wash is probably the right answer.

MacCool

Physics is physics. These friction concepts have been known since the time of Coulomb (18th century). You can prove the concept mathematically yourself using the formula I included above. Ffind the variable that represents contact area. (you can't....it doesn't exist)

Contact area has nothing to do with friction, and increasing contact area won't increase your traction. Now, if you're going to track the car, then you'll want wider tires for the same reason race cars use wider tires...to keep them from getting greasy when you really push them on the track. I'd be pretty surprised if more than a few people here on this forum had the skill to push their Z, even an FI Z, that hard on the track where the difference between 325's and 275's would affect your ability to run the car.

hermit

Well, I do plan to take the car to track. For the moment that will probably be occasional. Next summer I plan to do it more often. So, these tires will be for kind of a mix of both, mostly DD and some track. I'm stuck on whether I should take this current discount advantage on the S-04 or just go for the RE-11. Err, so indecisive.

hermit

I get it, it was just a talking point. Either-way, this helps in my decision. Currently I have 245/35 and 275/35, and I don't care to much for that "stretched" look as it has been stated by others. On the other hand I don't want to make the steering overly heavy. Which is my chief concern with going very wide. The extra heat dissipation will be a nice addition. But, more DD with occasional tracks for the moment. A bit more aggressive look is a plus, but not my intention (opinion). My biggest concern being the protection of the wheels really.

At first I was all in on the RE-11's. But, as this thread went on I've heard more about the S-04. As well I have come by more threads on it. I'm still indecisive between those two. But tire rack has a decent deal going on the S-04, which is swaying me that direction. Plus, it's Wisconsin I live in, our weather is just stupid sometimes. I always have my Xterra around for that though.

As far as size, based on everyone's help and suggestions. I think choosing a somewhat of a middle ground is best. I see what I have currently for size and I hate it to no end, I can post pics if anyone wants them. Grant it these tires are just crap. But, I do want wider, I just don't want to end up wider than what I am looking for. So, call it a stepping stone. I'll move up and when it comes time for new tires, if I want wider I'll go more wide at that time.

I'm thinking 265/35 front and either 285/35 or 305/30 rear.

Spooler

You can always try something and if you don't like it, go a different route the next set of tires.