Picking New Tires, Trying To Get More Front Grip

MacCool

Slip angle, rough surface traction, heat management, and therefore cornering performance, assuming you're pushing it hard enough to generate that much heat that it matters, are absolutely valid points in the discussion of traction vs friction. The OP is contemplating differing tires sizes to manage understeer/oversteer. Those factors don't come into play. He want's to "loosen it up" and "free it up a little more by getting more contact with the road with the front tires". We're back to high school physics.

Red__Zed

You're neglecting adhesion in your response. And oversteer/under steer is just f/r management of traction...

That basic equation assumes minimally elastic solids. Surface area matters more as the material becomes more elastic.

There are a lot of good resources to school up on traction out there. I'd recommend taking a look.

MacCool

The basic equation accounts for adhesion as part of the coefficient of friction. Surface area doesn't matter.

JARblue

Thank you for the enlightening response

Let me get this straight. You acknowledge those factors are all part of cornering performance, then proceed to state that since the OP wants to manage under/oversteer those factors don't come into play.

Want to try that again?

Or maybe you can explain how to induce understeer or oversteer without turning the steering wheel

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dP3NGU1N

Typical troll responses. Plenty of "you're wrong because I said so" with zero usable information pertaining to the OPs original question. Please stop wasting everyone's time. The rest of us are here for answers.

If you have a solution, state it. Otherwise, kindly feel free to fu[k right off.

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MacCool

The solution, obvious solution, to oversteering or understeering is suspension, not tires. I can't help it if your grasp of rudimentary physics is so lacking that these concepts are beyond your ability to understand. Public education apparently isn't what it used to be.

kenchan

like i stated on the other thread, we need to all run bicycle tires..

ScottOmatic

Thanks for your input guys,

I heed all of the info you have given, I understand the science of it may not be so cut and dry to understand but I will certainly listen to anyone that has gotten good results on their rides.

I did see the RE-71R's mentioned in another thread ( think it was the tail end of the RE-11 thread) but with the tire being one of the newest with less info on them, would like more info on road handling in the wet and tread life.

I drive the Z maybe 5,000 miles a year so tread life isn't the biggest concern, and if does fairly well in damp conditions, I might as well pick something in the Extreme Performance Summer category over Max Performance Summer Category.

My main thought with putting a wider tire on the front, such as the square setup was that even if you have a certain side ratio and wider tire width, with the rim only being 9 inches wide compared to 10 in the back, the tire might crown considerably more and the contact patch may be considerably different.

If people say 275/35r 19's all around are good, I certainly won't argue with that.

Or I can take Kenchan's advice and put bicycle tires on.... the back!

Red__Zed

To OP: I'd go square. Best modification I made for my Z's handling.

ScottOmatic

Hey it's cool guys...

Due to the wealth of info provided in this thread, I was able to pick out the optimal tires for my needs...

Rusty

The cards in the spokes are kick asss.

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dP3NGU1N

I can see this trend catching on with EVs so that the blind can hear them coming. =)

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Jordo!

Hmm. I was going to suggest a square set up as well, but really in order to keep tire size and compound a constant more than to play with relative grip -- a lot of that will depend on alignment settings and weight distribution/suspension more than anything.

I guess you could buy ultra sticky fronts relative to the rears, but that sounds like it will just make the car unpredictable...

So, assuming equal sized tires of same make, you want to stiffen up the rear relative to the front. That means a beefier rear anti-sway bar and firmer damper settings in the rear and softer in the front, if you can adjust them. Any other bracing you can add to the rear (without adding significant weight) will tend to nudge you more towards oversteer.

I think, maybe a little more camber in the front relative to the rear will help tuck the nose in too... not 100% certain on that one off the top of my head.

Scan over this site for lots and lots of advice on setting up cars for road racing

Autocross to Win (DGs Autocross Secrets) - ATW Home Page

This thread is helpful too

Suspension adjustments and how they affect handling

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ScottOmatic

GT Porsche 911 track cars often run harder rear compounds due to all the weight being over the rear axle but of course, those are engineered to work correctly from the tire supplier and the rest of the setup is dialed in in every other aspect along with track time.

I think running 2 different street tires with different compounds and different tread patterns that are meant and have only been tested running on all 4 corners is hairy at best.

Even if the effect is generally positive in the dry it could be a nightmare in the wet.

As you touched on, the other idea I have had was upgrading the rear sway-bar and leaving the front alone. This would be a pretty cheap upgrade and I could always add the front later when getting new springs/struts or Coil-Overs, which I am sure would take out most of the understeer with default tire sizes.

The reason I don't want to just spend the money on a full suspension setup right now is that I am trying to pay off my 2014 FJ Cruiser early (that currently takes precedence when funneling money into cars) and to be honest, I am slightly worried I will get the bug for a different sports car in a few years and know it will be hard to get my money back in upgrades (Currently under 23,000 miles on my Z so everything but the tires are still pretty fresh).

Maybe I will get some new suspension components in awhile, maybe I will eventually get a tune, but until I make that decision I am going with the bang for the buck approach.

I should say I already bit the bullet on a cat-back exhaust a year ago, I'm sorry but the default exhaust setup just had to go!

Rusty

You should read the track section. Everyone is running the stiffest front bars, and the biggest tires they can. Some are running no rear bar at all.

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