Now that we know HOW to improve Handling in a car,

[Heisenberg]

Originally posted by: Vic
2a) coilovers
4) bushings
5) custom alignment

edit: Kelvrick is right, weight and weight distribution. I also forgot brakes.

Also sub-frame connectors, trailing arms, pan hard rod.

 

[Zenmervolt]

Originally posted by: Ornery
"different tires serve different purposes"

Yeah, some are for real racing, and some are for poseur racing.

ARTICLE 12: WHEELS AND TYRES

• 12.1 Location:
  Wheels must be external to the bodywork in plan view, with the rear aerodynamic device removed.
  12.2 Number of wheels:
  The number of wheels is fixed at four.
  12.3 Wheel material:
  All wheels must be made from an homogeneous metallic material.
  12.4 Wheel dimensions:
  12.4.1 Complete wheel width must lie between 305 and 355mm when fitted to the front of the car and between 365 and 380mm when fitted to the rear.
  12.4.2 Complete wheel diameter must not exceed 660mm when fitted with dry-weather tyres or 670mm when fitted with wet-weather tyres.
  12.4.3 Complete wheel width and diameter will be measured horizontally at axle height when fitted with new tyres inflated to 1.4 bar.
  12.4.4 Wheel bead diameter must lie between 328 and 332mm.

There is NO mention that the sidewalls have to be wide. The wheel size is fixed, but not the tyre profile.

I'm sorry Ornery, but you're not seeing the forrest because you're standing too damn close to a single tree.

The wheel diameter is fixed, yes. However, a low profile tire on those wheels would be too small for practical gearing. The overall tire diameter is a critical part of the car's overall gearing and using low-profile tires would put the overall tire diameter below the acceptable minimum limit.

But I suppose that the fastest class of cars at LeMans must be using low-profile tires because they slow the car down and make it handle worse. Yeah, that must be it.

ZV

EDIT: And these ALMS racers must be morons for running low-profile tires.

These guys must be stupid too.

Look, another dumbass racing with low-profile tires. Wait, this guy dominates his class.

Wow, even the factory-backed Corvette team.

 

[mAdD INDIAN]

Originally posted by: Ornery
"different tires serve different purposes"

Yeah, some are for real racing, and some are for poseur racing.

ARTICLE 12: WHEELS AND TYRES

• 12.1 Location:
  Wheels must be external to the bodywork in plan view, with the rear aerodynamic device removed.
  12.2 Number of wheels:
  The number of wheels is fixed at four.
  12.3 Wheel material:
  All wheels must be made from an homogeneous metallic material.
  12.4 Wheel dimensions:
  12.4.1 Complete wheel width must lie between 305 and 355mm when fitted to the front of the car and between 365 and 380mm when fitted to the rear.
  12.4.2 Complete wheel diameter must not exceed 660mm when fitted with dry-weather tyres or 670mm when fitted with wet-weather tyres.
  12.4.3 Complete wheel width and diameter will be measured horizontally at axle height when fitted with new tyres inflated to 1.4 bar.
  12.4.4 Wheel bead diameter must lie between 328 and 332mm.

There is NO mention that the sidewalls have to be wide. The wheel size is fixed, but not the tyre profile.

I don't know who this guy is, but his explanation sounds as plausible as anyone's, and I agree:

"I also think that if we went to low profile tires, they'd be less of a factor as far as any advantage over one another. "

You just proved my point about F1 tires without looking at other racing series. Why not read some in-depth articles on the physics of tires in F1. Low-profile tires will not work there since they cannot handle the stresses.

But did you NOT read what I said about other series?? SCCA racing series uses the same low-pro tires that we use because it greatly benefits them, the same way it benefits a street car. Don't believe me? Goto a local lapping or auto-x session and see what they use.

You said:

When the wheel camber changes during cornering an extremely low profile tyre cannot keep as much footprint on the road.
Watch the F1 slo-mos through corners and you can see them suffer the same problem.

With modern cars, the wheel camber dynamically changes during cornering. Most sports car use some form of double-wishbone suspension that keeps the wheels perpendicular to the road (regardless of road irregularities). And if they have low-pro's with stiff sidewalls, then the tires flex less which allow their contact patch to be consisent during the corner. To observe this for yourself, put some chalk on the outer edge of the sidewall of regular tires and go take some turns...and then when your done. Look to see how much chalk remains. Try it again with low-pro tires with stiff sidewalls...and see the difference.

Back to the thread topic:

Lowering your car will not always increase handling because if you lower too much, you can change the suspension geometry for the worse. It may be fine to lower by an inch or so, but some of those guys who "tuck" the cars are not doing themselves a favour (suspension wise). It's stupid and pointless.

Now your gonna say, well those touring cars and other race cars are so low compared to their street counterparts. Well that's because their suspension hardpoints are changed...so instead of puttign the tires closer to the chassis, they put the chassis closer to the tires. This way they can maintain optimal suspension geometry (of course they do other stuff to...but I'm simplifying it).

Stiffening up the chassis with subframe connectors and/or properly welded beams in the right place can do wonders. As does replacing bushings, reducing weight, changing tires, adding sway bars, dampers, and most of all, increasing your driving skill.

If you can't handle your stock vehicle at the limits, how the hell will you manage with a modified one?

 

[Ornery]

There's 3 times as much sidewall on these tires as these! Why so much on the real race wheel/tire, and so little on the poser-mobile?

 

[mAdD INDIAN]

Originally posted by: Ornery
There's 3 times as much sidewall on these tires as these! Why so much on the real race wheel/tire, and so little on the poser-mobile?

because those dry tires in the pictures are slicks. You'll never find low-profile slicks because it isn't physically possible since they would be too soft to have any strenght. Also they expand/contract upon heat and you need room for that.

The ricer car picture uses STREET tires not SLICKS.

 

[Zenmervolt]

Originally posted by: Ornery
There's 3 times as much sidewall on these tires as these! Why so much on the real race wheel/tire, and so little on the poser-mobile?

Again, you are choosing to completely disregard any point and continue to be willfully contrary.

I explicitly stated in one of my earlier posts that there are tradeoffs associated with moving to lower profile tires and that simply moving to the lowest profile possible is not always the best thing because of other considerations and VIC has posted exceptional information.

There is also the issue of suspension compliance in racecars as well. The suspension on race cars is generally so stiff that the tire itself is the only thing that can absorb any type of bump quickly. On a road car, or even a streetable race car, the suspension is much softer and is capable of handling those high-frequency bumps without as much compliance from the tires.

Go to an SCCA event or check out a local PCA autocross or track day. You'll find that the best drivers with the fastest cars are running low-profile tires in addition to their suspension modifications.

ZV

 

[TechnoKid]

Originally posted by: mAdD INDIAN


Back to the thread topic:

Lowering your car will not always increase handling because if you lower too much, you can change the suspension geometry for the worse. It may be fine to lower by an inch or so, but some of those guys who "tuck" the cars are not doing themselves a favour (suspension wise). It's stupid and pointless.

Often times, you will see low cars that just do not handle well, sure the center of gravity may be much lower, however, if you do not have sufficient suspension travel, you will bottom out on bumpstops when cornering, and bottoming out is not good for handling. I think suspension travel is one of the most afterlooked things when lowering a car for increased handling, though most people who do lower their cars don't do it for better handling. Anti-sway bars and the proper valved shocks and matched spring rates make a huge difference if all properly tuned. Caster and camber are probably the most important things to consider when aligning a car, toe too, because caster and toe can adversly affect the turn-in on a car.

 

[Ornery]

Topic Summary: but how about Handling??

Handling for what? Where?

Why do consumer "F1 tires" bare no resemblance to real F1 tires?

 

[mAdD INDIAN]

Originally posted by: Ornery
Topic Summary: but how about Handling??

Handling for what? Where?

Why do consumer "F1 tires" bare no resemblance to real F1 tires?

That's marketing for you.

Back to the question you posed, that's a very good one. Most often, people don't realize that there are different types of good handling.

Do you want exceptional grip while sacrificing ride quality? Do you want grip for performance/aggressive driving or just for emergency manueavers? Do you want precise feel of the car or just grip? Or both?

The way the OP posted his question, I'm inferring that he wants to increase the mechanical grip of his car so he can be competitive in autox/lapping events. In that case, tires and driving skill make the biggest difference. Once you accomplish those, then you can work on getting other parts to enhance handling AND feel of the car.

Case in point? A dude in a rusted out early 90s Oldsmobile Cutlass Ceira on wide summer tires kicking my ass, along with many others (including BMW 5-series and Integras) in an auto-x event. He had 15years of experience in auto-x and was a very good driver. Also a dude in STOCK Cavalier Z24 on r-compounds. He posted FTD for his class. I've used these examples before and I'm using it again because they deliver the point.

 

[Viperoni]

There's also the strengthening of suspension components, such as control arms, and reinforcing the frame/unibody through a rollcage or subframe connectors.

 

[Apex]

Originally posted by: Ornery
Topic Summary: but how about Handling??

Handling for what? Where?

Why do consumer "F1 tires" bare no resemblance to real F1 tires?

The Goodyear Eagle F1's use similar technology to F1's wet weather tire, not the F1 dry slicks.

 

[mAdD INDIAN]

Originally posted by: Apex

Originally posted by: Ornery
Topic Summary: but how about Handling??

Handling for what? Where?

Why do consumer "F1 tires" bare no resemblance to real F1 tires?

The Goodyear Eagle F1's use similar technology to F1's wet weather tire, not the F1 dry slicks.

but Goodyear isn't even in F1 for the past few seasons so how would that work?

 

[Ornery]

"...competitive in autox/lapping events..."

I'm thinking 99% of the people who mod their cars, be it the engine, or suspension, never see a track. This includes the OP. I'm saying you can get rid of the crap tires the manufacturer sold with the car, replace them with the exact same profile tires, and get MUCH better handling via better tire compounds and general design. All without inducing harshness, and maintaining the ability to drive over a curb or speed bump!

 

[mAdD INDIAN]

Originally posted by: Ornery
"...competitive in autox/lapping events..."

I'm thinking 99% of the people who mod their cars, be it the engine, or suspension, never see a track. This includes the OP.

Why would you say that? Why modifiy a car's performance parameters if your not gonna put it to use?

I'm saying you can get rid of the crap tires the manufacturer sold with the car, replace them with the exact same profile tires, and get MUCH better handling via better tire compounds and general design. All without sacrificing harshness, or even the ability to drive over a curb or speed bump!

You definately can. No one denied that. But you'd get EVEN better performance if you went to a low-profile version of the performance tire.

Also you must realize that most performance tires have lower profiles to begin with. Not super low like the example you presented, but still lower than OEM tires on say, a regular family sedan. It's hard to find performance tires with hte profile of a 205/60 R15 tire.

Altho speaking of OEM tires, a lot of new sporty cars come with low-profile tires from the factory.

 

[Ornery]

They'll put it to use alright, on the same streets you and I use to commute! The same streets filled with potholes, debris, gravel, oil and other spills. The same streets that are easily navigated by tractor trailer rigs. Makes you wonder why they even need these suspension mods, eh?

I KNOW they're putting lower profile tires on cars. This is most likely consumer driven, just like spoilers and ground effects crap. The cars certainly don't need these things on our city streets. My wife's G. Marquis came with 16" wheels and the ride IS harsh! It's STUPID! Cop cars use 15" wheels on the C. Vics. Why do you suppose that is? You'd think they would need better performance than my wife, wouldn't ya?

 

[Apex]

Originally posted by: mAdD INDIAN

Originally posted by: Apex

Originally posted by: Ornery
Topic Summary: but how about Handling??

Handling for what? Where?

Why do consumer "F1 tires" bare no resemblance to real F1 tires?

The Goodyear Eagle F1's use similar technology to F1's wet weather tire, not the F1 dry slicks.

but Goodyear isn't even in F1 for the past few seasons so how would that work?

Who said it was current F1 technology?

 

[Zenmervolt]

Originally posted by: Ornery
"...competitive in autox/lapping events..."

I'm thinking 99% of the people who mod their cars, be it the engine, or suspension, never see a track. This includes the OP. I'm saying you can get rid of the crap tires the manufacturer sold with the car, replace them with the exact same profile tires, and get MUCH better handling via better tire compounds and general design. All without inducing harshness, and maintaining the ability to drive over a curb or speed bump!

Well duh. But you didn't say that before. At least not in such a way that made it clear that you were talking about street-only use. The rest of us were discussing things for a race or at least semi-race setup.

ZV

 

[mAdD INDIAN]

Originally posted by: Ornery
They'll put it to use alright, on the same streets you and I use to commute! The same streets filled with potholes, debris, gravel, oil and other spills. The same streets that are easily navigated by tractor trailer rigs. Makes you wonder why they even need these suspension mods, eh?

I KNOW they're putting lower profile tires on cars. This is most likely consumer driven, just like spoilers and ground effects crap. The cars certainly don't need these things on our city streets. My wife's G. Marquis came with 16" wheels and the ride IS harsh! It's STUPID! Cop cars use 15" wheels on the C. Vics. Why do you suppose that is? You'd think they would need better performance than my wife, wouldn't ya?

you think the ride is harsh on a Grand Marquis?? WTF?

Buddy, you don't know what harsh is.

 

[Zenmervolt]

Originally posted by: Ornery
Cop cars use 15" wheels on the C. Vics. Why do you suppose that is? You'd think they would need better performance than my wife, wouldn't ya?

No. Police cruisers are heavy, slow, and poor-handling. They use the radio and helicopters to overcome that.

Despite what you may think, police cars are not high-performance machines in any stretch. My stock Mark VIII would have no difficulty, given equal driver skill, in outrunning a single police cruiser. But what the difference is is that police officers are highly trained in vehicular control and they have the good old Motorola to being in more officers well ahead of where you are on the road.

ZV

 

[Ornery]

I don't know how it is today, but it used to be, when you purchased a "police package", you got a beefy engine, with modded guts, better cooling, AND heavier suspension components. I would think today they would AT LEAST put the optimum wheel and tire combo on a "police package". What I see beeing used is 15" wheels, not 16 or 17". I suspect that is optimum for cruising city streets.

I also find it amusing how many people talk about racing and "twisties", but probably will never drive on a track in their lifetime. I assumed this topic was no different...

 

[Evadman]

Some cop cars are pretty damn good at performace though Zenmervolt. But not the standard ones. My town (of rich fvcks) has an old lambo, a vette and a mustang. Don't ask me why.

 

[mAdD INDIAN]

Originally posted by: Ornery
I don't know how it is today, but it used to be, when you purchased a "police package", you got a beefy engine, with modded guts, better cooling, AND heavier suspension components. I would think today they would AT LEAST put the optimum wheel and tire combo on a "police package". What I see beeing used is 15" wheels, not 16 or 17". I suspect that is optimum for cruising city streets.

I also find it amusing how many people talk about racing and "twisties", but probably will never drive on a track in their lifetime. I assumed this topic was no different...

All the police cars get now are better cooling components (beefed up radiator, oil and tranny cooler, etc..) along with heavyduty suspension components (to deal with increased weight, not performance) and increased electrical power (more powerful alternator, etc..).

That's it. Gone are the days of increased power.

And I don't see why you don't think people wouldn't goto the track, I have as well as many other members of this forum.

 

[Aharami]

Originally posted by: Ornery
Tires are critical, and since they need to be replaced anyway, it's an economical "upgrade". BTW, what's the deal with the paper thin sidewalls? What do these boneheads know, that these guys don't?

im no car nut. but maybe for extreme high performance uses like the F1s...thicker sidewalls are better.

but i recently switched from 16" wheels with stock Michellin tires to 18" wheels with Pirelli all season tires. Now it maybe the Pirelli tires...but my handling and cornering abilities has shot thru the roof with the new wheel/tire setup

 

[Ornery]

I only had one acquaintance who ran in Autocross and rally events. A couple... actually only one co-worker (Edit: just remembered the second one) who raced at a drag strip. But by God, there are so many I've known with pseudo race cars having a go around town.

There are thousands of members here with "sports cars". What percentage do you think will EVER race at a track? Even just the ones who insist on having manuals, because they "want to be one with their car." :roll: What percentage of them will ever race at a track? I'm thinking 5% at most!

 

[Aharami]

Originally posted by: Vic

Well, yes and no. The issue is to keep the unsprung weight to a minimum, and bigger wheels add more weight than bigger tires.

not true for all cases. my 16" wheels with Michelin all season tires with hardly any tread left weighed about 41lbs per wheel/tire combo. my new 18" 18.1 lbs O.Z. wheels with Pirelli all season tires weigh 39 lbs