So I just had a bit of a debate with my buddy at college, and well, now neither of us is really sure what the outcome was... And I can't find a good answer online.

We were talking about car handling, and he said something to the effect that making a car wider will make it handle better... I said that there shouldn't be any reason that that is true based on physics, assuming that you are not changing the center of mass and the weight stays constant... The contact patch should still be the same too. But it just seems right somehow that a wider car handles better, though I can't find any physical reason for it to...

Now if you widen a car and are able to move the center of mass lower because of this, it may handle better because it will have a lower center of gravity. That seems right to me.

We also thought of rotational inertia (yes, we are both studying to be mechanical engineers), a wider car would mean more rotational intertia as the car's body rolls... more weight to the edges, so it takes longer to transfer weight I think... but then why are many racing cars widened?

That fact leads me to believe we might be overthinking this, and it doesn't really make all that much difference in comparison with other factors like tire width, suspension geometry, and center of mass height? but I really dunno, that's why I'm asking.

By car width do you mean the track?

If so wider track generally means better turn in and more "Go-kart" like handling.

it also depends on suspension design, how far over the wheels the body hangs etc etc. But generally a low wide car is going to give better results in regards to cornering.

Whenever i see a lambo/ferrari kinda car IRL it surprises me just how wide they are, the pictures you see don't really do them justice.

Things like wheelbase (length between wheels front to rear etc) will also effect the handling. A car with a longer wheelbase will generally have a more predictable/slow transition characteristic from grip to slide, whereas a short wheelbase vehicle is more likely to be "snappy" or "twitchy" in the way it handles, transitioning very quickly from grip to slide.

IIRC tho making a cars track wider can also have undesired effects like causing understeer etc, especially at lower speeds...but i may be talking shit.

Handing =/= Grip.

Wider track will result in more grip at that end (or overall if both are increased) due to reduced load transfer. But not necessarily in better handling.

Handling is how the car behaves to inputs, how much feedback and confidence it gives, how balanced it is etc, and has nothing to do with grip. Indeed, most aftermarket additions increase grip at the EXPENSE of handling.

What Tristan says is true, except I disagree about the last statement. I find the most obvious effect of, let's say aftermarket suspension parts, is reduced grip with a perceived effect of better handling in some situations, especially as perceived by people with very little experience in handling cars.

Lowering of a street car usually results in ruining the geometry of the suspension. With the arms in a McPherson setup pointing 'upwards' toward the wheel, you'll get snap over/understeer with sudden positive camber.
Oh yes, this is only one of many possible negative effects of lowering a street car.
The feeling of a lower CoG means that the car will feel more like a kart. The car is a freaking death trap though.

I've generally found that lowering a car or putting on silly suspension (usually termed coilovers, even though the original suspension has the coils over the dampers) is to increase grip - i.e. you can corner faster before the cars starts to slide/spin.

But once it does start to slide, the behaviour of the car is much more violent and much less predictable. Hence I believe that grip is greater, but handling is worse.

Which is why so many morons in modified cars end up in hedges backwards (apart from the fact that less than 1% of under 30 male drivers has even an iota of talent behind the wheel of a car).

Quote from RasmusL :

especially as perceived by people with very little experience in handling cars.

It seems you're one of them.

Quote from RasmusL :

With the arms in a McPherson setup pointing 'upwards' toward the wheel, you'll get snap over/understeer with sudden positive camber.
Oh yes, this is only one of many possible negative effects of lowering a street car.
The feeling of a lower CoG means that the car will feel more like a kart. The car is a freaking death trap though.

For one, lowing a car gives you NEGATIVE camber, not positive.
Second of all, generally when people lower a car, (Providing its not dumped on the ground) it doesnt take much more than a wheel alignment to correct these issues.

Quote from Klutch :

For one, lowing a car gives you NEGATIVE camber, not positive.

You can experience sudden positive camber gain when a McPherson strut reaches its limit of travel, and that effect amplifies when you drop the car and shorten the spring. The more static negative camber you put in a McPherson suspension, the sooner you will reach that stage of positive gain.

How often would you reach its limit of travel though...?

Quote from Klutch :

It seems you're one of them.


For one, lowing a car gives you NEGATIVE camber, not positive.
Second of all, generally when people lower a car, (Providing its not dumped on the ground) it doesnt take much more than a wheel alignment to correct these issues.

Oh you are so very wrong. When the angle between the control arm and strut exceeds 90 degrees (usually when a street car is lowered more than 2-3 cm), the suspension experiences a loss of negative camber under roll. You cannot do a wheel alignment on a McPherson to correct this effect.

Additionally, this angle between control arm and strut causes the distance between the roll center and CoG to increase. This distance is the imaginary lever by which force works to cause body roll in the car, and it is increased faster by lowering than the CoG can compensate for. Do I have to explain to you what a lever arm does too? A lower car will in this case experience MORE body roll.

not exactly the very limit, but if you have a car lowered by say an inch, but without stronger springs or anti-rolls throw in, you might experience camber gain maybe 65% to 70% compressed, which can happen quite often in serious cornering - that differs from design and geometry without saying.

Forgive my ignorance on mcpherson setups because i've only ever dealt and looked into double wishbone.

Quote from RasmusL :

You cannot do a wheel alignment on a McPherson to correct this effect.

Why not? You can on a double wishbone, i know mcpherson isn't exactly as 'fine' tuneable, but theres plenty of adjustable parts out there for them.

Quote from Klutch :

Why not? You can on a double wishbone, i know mcpherson isn't exactly as "fine' tuneable, but theres plenty of adjustable parts out there for them.

The problem is the more static negative camber you put in, the more serious the effect will become. So you just can't fight it with dialing in more camber.

it is relative to chassis roll though, so if you can limit the amount of roll, you can prevent it from happening. But that also means you are more compromised in terms of stroke and travel.

hmm, fair enough

learn something new every day

Truth is you need much more than a wheel alignment to correct this. Even if you have static negative camber, you will under cornering experience dynamic positive camber. It is really a feature of the McPherson setup, and the reason it is bad for performance driving. Lowering it beyond a very specific point is simply making bad worse.

Now, the best you can do is finding SHORT coilovers that are very adjustable, and springs that compensate greatly for the much shorter jounce travel.
I don't have a lot of experience in aftermarket parts, but I would guess that they mostly use quite soft springs in their kits, because modders would complain if they realized how hard their car should actually be.

I've actually looked into some aftermarket suspensions myself, most "sporty but streetable" suspensions kits are no more than 30% harder overall than stock, unless on cars like EVO that are exceptionally soft say on the front end to reduce understeer. And those drop maybe just half and inch at most

To get proper track ready spring frequences you often need springs three times as hard as stock, and that on public road is simply unbearable.

Quote from RasmusL :

but I would guess that they mostly use quite soft springs in their kits, because modders would complain if they realized how hard their car should actually be.

Only if you buy cheap china shit.


When you buy them new from somewhere reputeable you can usually specify your own spring rates, or just get the "standard/recommended" coilover that they offer.

Quote from JJ72 :

To get proper track ready spring frequences you often need springs three times as hard as stock, and that on public road is simply unbearable.

Unbearable is relative.

Having been in an R32 skyline with JIC golds 18kg fronts and 14kg rears, while it was bumpy it certainly wasn't unbearable.
Would be a little different on country roads though..

If you let people choose their own spring rates there is even less chance of them being correct. Modders know less than nothing in the vast majority of cases and think that lower and stiffer is better. Which is rarely is.

Quote from tristancliffe :

Modders know less than nothing in the vast majority of cases and think that lower and stiffer is better. Which is rarely is.

Your generalisations annoys me.

Not everyone is "HUR DUR MY CARS UBER LOW AND MY EXHAUST IS LOUD MY CARS AMAZING AND FAST"

some people modify cars for better performance and actually put effort into finding out what best suits the car(and them)

Quote from Klutch :

Your generalisations annoys me.

Not everyone is "HUR DUR MY CARS UBER LOW AND MY EXHAUST IS LOUD MY CARS AMAZING AND FAST"

some people modify cars for better performance and actually put effort into finding out what best suits the car(and them)

The soarer isn't quite a good example for that however.

You say that like i choose what goes on the car?

And i don't see the downside to stiffer suspension, better brakes, and more power.

But its also not a weekend track car, nor is it competetive.
If it was more motorsport orientated it would have no interior and more suspension than go-fast mods.

The only form of motorsport it sees are the occasional motorkhana and a thrash through the hills.

Quote from Klutch :

Having been in an R32 skyline with JIC golds 18kg fronts and 14kg rears, while it was bumpy it certainly wasn't unbearable.
Would be a little different on country roads though..

1. You have never seen the roads over here, it put all rally stages to shame. most of them are not even tarmac, more like cement mixed with some extra...stuff.

2. I have a boney ass.

Quote from Klutch :

Your generalisations annoys me.

Not everyone is "HUR DUR MY CARS UBER LOW AND MY EXHAUST IS LOUD MY CARS AMAZING AND FAST"

some people modify cars for better performance and actually put effort into finding out what best suits the car(and them)

Stiffer springs - are you sure it's better? How do you know? What about traction and performance over bumps? Why do racing cars tend to use the SOFTEST springs they can, yet car modders use the stiffest? Which group are more likely to know what they're doing?

Better Brakes - brakes are only as good as the tyres, driver and suspension. Fitting a $5000 AP Brake Upgrade might INCREASE your braking distances if everything else remains equal.

More Power - Really? In all conditions? On the road over 90% of driving is less than 60km/h and 50% throttle. It's doubtful that most 'power' mods give more performance in this area. It's doubtful that a lot of power mods increase power or torque at all, even when sold with "dyno charts that prove it".

I just don't see the point of modding. You will NOT be quicker point to point on the road than a standard car as blind bends, traffic conditions, road works and all of that will mean a standard car would be able to complete the journey in the same amount of time, but using less fuel, making less noise, and looking less silly. A standard car will be more comfortable. Just as fast. Cheaper to use and insure...

As far as I can see it (and remember, I like spirited driving in decent handing cars as much as the next loon) modding a car is throwing money at it to make it worse at the job it's meant for.

I am not moved by performance claims, and 'researching' car mods on the internet and doing what others have done usually results in making the same mistakes as everyone else - who probably have even less of a clue than you do.

But that's my opinion, and the topic is about wider track improving handling, which it might do, but just as equally might destroy.

Tristan has largely covered this but:

Quote from Klutch :

And i don't see the downside to stiffer suspension, better brakes, and more power.

Stiffer springs: you're more likely to bounce off a bump or pothole, lose traction, and have a fatal collision with a tree. More useful to adjust the roll balance to remove the understeer, thus improving handling.

Better (?) brakes: increased resistance to fade is useful for hard driving in cars that weren't designed to take it (which includes much higher spec cars than you would have thought). Before fade becomes an issue though, the increased rotational weight will slow your car, the increased unsprung weight worsen the handling, and the increased pedal sensitivity will make it to modulate the brakes in normal circumstances. There is a reason race cars use the smallest brakes they can (NASCAR sprint cup cars at superspeedways, for example, only brake when entering the pits, so have brakes just large enough to not melt or exploded when they brake from 200mph to stopped in a few seconds).

More power: while fun, also has the potential to mean when you do have your accident from over-spirited driving, you'll probably be going faster so it will hurt more.

Easily solved. Roll centre adjustment kit.

Also saying you've made a car more dangerous by upping the spring rates etc is a bit broad. I've owned standard cars that NEEDED more spring rate, as they boated around like a boat rolling in a large swell when cornering. I've also owned cars that i've upped the spring rates in for weekend track use and made them slower to drive on the road, because they feel less planted on uneven surfaces, even with correctly matched damping. But i wouldn't drive that car on the road everyday to work etc.