can a car be too light?

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Sharkiex

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sharkiex38
there has been many good threads on suspension tuning but not one on weight reduction for cars.

can a car's weight be reduced so much as to deprive handling? i feel that the lighter the car, the more floaty it feels when going over 140 mph. at the Nur, this is a problem for the hight speed but bumpy sections.

to compensate for lighter weight, i feel that more downforce is needed. this is a problem for some cars such as the lfa which doesnt have aero. i feel it is better to keep the ful weight and just utilize the extra power.

less weight equals less tire load equals less grip.

any thoughts on this?

also if you have very light cars, do you need harder softer springs?
 
I don't think there's "too light", as long as it's tuned right, unless you're looking at a PP limit. Ultra-light cars, like the Mini Marcos or the Ginetta G4, are rated way higher in PP than they should be due to their extremely light weight. I've got a fully modded Marcos that weighs in at 515 kg and sticks to the road like glue on any track with sports soft tires.

Sadly, at 167 HP and 515 kg, it gets rated at 512 PP, even though it runs laps equivalent to normal cars at around 50-75 PP lower. Still a tune in progress, but the lack of accelleration kills me.
 
omg I just tuned a Lotus Elise but this is a special one that goes down to 648kg at 329hp. The thing fly's and if you are not a good driver the extreme lightness will freak you out. It feels crazy especially on bumpy tracks. The lighter the car the better no matter what, but you have to re-adjust your own driving style to it. You have to just practice with that car and understand the track you plan on racing before any major events.
 
without knowing the car and the current tune, it's hard to say which way to go... especially for me, as I'm not much of a tuner, more of a tweaker :)
 
Sharkiex
less weight equals less tire load equals less grip.
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Only under acceleration or braking. When cornering, centrifugal force overwhelms whatever grip that weight provides at the contact patch and you lose grip. From a handling perspective, the ideal weight for a vehicle is as close to zero as possible
 
with a light car you can make the car lower and/or softer. If the car still has ride height nearly standard, I think making the car lower definitely is the easiest and best fix.

If the car is already very low and is very high power maybe try softer bound instead of fiddling with springs. A light car may also go better with less anti-roll.
 
The only car I can think of that is too light, is the Caterham. And the only reason I say it's too light is that it takes forever to get any heat into the tyres. On some tracks, you'll never get the tyres up to operational temps. Of course this only matters when participating in races that have tyre wear and/or grip set to real.

However, this car is a one off, in my humblest of opinions. The general rule of thumb would suggest that lighter is better. In terms of what you would do with your suspension, I'd soften your springs. To get to a starting point for a build, I tend to balance the springs in relation to weight distribution. I then make adjustments for any weight changes, softening springs for weight loss, and hardening for weight gain. I also make adjustments according to the tyres I'm running, hardening springs as the compound of tyre gets softer and visa versa. I have a simple spreadsheet that helps me calculate these initial rates, just requires the weight distribution, stock weight and desired weight, length of spring travel, stock tyres and desired tyres. The calculations are rudimentary and I've no real evidence to back up that they work or make the slightest difference. I'll wait and see if I can get some input before splashing my school boy maths across the community.

After I've taken the car out for a spin, I then make final adjustments to the springs depending on how the car drives. After I've established spring rates I'm happy with, I'll go about the rest of the suspension...

{Cy}
 
I posted because I feel my nsx at 1038kg doesn't feel stable a high speed. It lacks downforce, I think, even though I already have the max 20
 
Pagani Zonda 7.3 fully upgraded is too light for 900 hp and not enough downforce.
 
There's no short answer for this, you may have to switch up your style with a car when you lower the weight. If you're approaching a jump like the one on cape ring you'll need to slow down more if you plan on landing before the point where you need to start applying the brakes. On the other hand, you can brake quite a bit later when you don't have the weight adding to your sideways momemtum as you go through the next corner, and lighter cars are easier to stop.

Loose and tight handling is caused by the distribution of the weight, not the total.

Lower weight requires/allows a lower spring rate than a heavier car.

Its ALWAYS beneficial to lower the weight because ballast is adjustable, while the stock weight is stationary. Even the 7.3 is easier to drive with 200kg ballast on the front than it is at the stock weight, and the acceleration with less than 200kg will break your neck :)
 
oppositelock
Only under acceleration or braking. When cornering, centrifugal force overwhelms whatever grip that weight provides at the contact patch and you lose grip. From a handling perspective, the ideal weight for a vehicle is as close to zero as possible
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Exactly, even the lack of grip during braking or acceleration is offset by the fact that a lighter car starts and stops faster with less effort by the engine or brakes.
 
Sharkiex
I posted because I feel my nsx at 1038kg doesn't feel stable a high speed. It lacks downforce, I think, even though I already have the max 20
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Can you post your settings? There might be something set up wrong thats causing you problems.
 
With no other factors to consider lighter is almost always faster. However, under the pp system:

Less weight = less hp.
Less HP = less accel at the top end and maybe less accel generally depending on how PD has modelled the pp system.

You have to do a lot of experimenting to find the balance. What I've generally found is that in the lower PP levels where a lot of corners are wide open or very nearly so, taking off weight and resulting HP is too much of a penalty in terms of accel and top speed. This is especially true the softer the compound because with softer compounds many more corners are at or near top speed anyway.

If you want to experiment, take a car like the RX8 Type S 07' from the NCD and leave it at stock weight and set it up for 450ppSS. Then do a full weight reduction and compare lap times at power tracks like Road Course Indy and handling tracks like Trial Mountain and Deep Forest.

It's also important to remember you're not dealing with real world physics here, it's a video game. I see a lot of real world physics and car tuning principles mentioned above that may or may not apply to this game.
 
I'm a tuning noob and I found a tuned up Fireblade easier to drive after I added ballast to meet the requirements for the British Lightweights seasonal event ( 80+ KG).
 
IRL you cant really be too light. Thats why you see race cars with plastic or cf body panelsvall the time. In game though there is avpoint were you can be to light for either your tire compound or your power level. Not sure on weither or bot thays because of the physics engine or lack of more in depth tuning options though.
 
oppositelock
Only under acceleration or braking. When cornering, centrifugal force overwhelms whatever grip that weight provides at the contact patch and you lose grip. From a handling perspective, the ideal weight for a vehicle is as close to zero as possible
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centrifugal force is a myth.......it doesnt actually exist.....The only forces on you when you are cornering are gravity, the normal force that complements, and the friction from the tires that keeps you going in around the turn.
 
Blaze_409
centrifugal force is a myth.......it doesnt actually exist.....The only forces on you when you are cornering are gravity, the normal force that complements, and the friction from the tires that keeps you going in around the turn.
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Aren't you forgetting vehicle inertia? Centrifugal force is known as a fictitious force, that doesn't mean it's a non-existent phenomenon, otherwise the term wouldn't exist. I'm not going to get bogged down in semantics, the point is extra mass resists the vehicle from wanting to change direction when you turn the wheel. From the perspective of the driver that means less grip and the car wanting to push towards the outside of the corner. You can call it whatever you want to call it, my point stands.
 
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racer39658
I don't think there's "too light", as long as it's tuned right, unless you're looking at a PP limit. Ultra-light cars, like the Mini Marcos or the Ginetta G4, are rated way higher in PP than they should be due to their extremely light weight. I've got a fully modded Marcos that weighs in at 515 kg and sticks to the road like glue on any track with sports soft tires.

Sadly, at 167 HP and 515 kg, it gets rated at 512 PP, even though it runs laps equivalent to normal cars at around 50-75 PP lower. Still a tune in progress, but the lack of accelleration kills me.
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mmm ur marcos seems a little low in the hp department.

i get 194 hp max parts. try tsukba (sp) i get 59:989
 
Car that is too light for it's own good? Ginetta G4. Gods, how much I hate that car.. it was bad in GT4, now it's even worse. Even with almost no power whatsoever it still handles worse than a 1000bhp Viper.
 
Blaze_409
centrifugal force is a myth.......it doesnt actually exist.....The only forces on you when you are cornering are gravity, the normal force that complements, and the friction from the tires that keeps you going in around the turn.
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Yea, and 9/11 was a conspiracy and the Holocaust never happened. Sure...
 
No, you can not make a cars cornering speeds slower by reducing weight.
What it can do is make a car harder to drive.
 
Schwartz38
Yea, and 9/11 was a conspiracy and the Holocaust never happened. Sure...
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9/11 was a conspiracy...a conspiracy of mostly Saudi terrorists to destroy the Twin Towers...

Anyway, as often happens in this game, everyone bandies about different real life ideas as if they must somehow apply directly to the game. They do not. So talking about centrifugal force or gravity or moments of inertia or any real life physics is completely irrelevant. The only thing that matters relating to how a car drives is how PD modelled the physics, not real life physics.

As has been talked about in many, many different threads, some aspects of reality are modelled well in the game, some not so well, and some probably not at all. Some may or may not be backwards. You need to work within what the game gives you, not what you think it should be according to the real world.
 
Johnnypenso
9/11 was a conspiracy...a conspiracy of mostly Saudi terrorists to destroy the Twin Towers...
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You don't really know what you're talking about, do you?
Where's the facepalm smilie when I need it?
 
Johnnypenso
Anyway, as often happens in this game, everyone bandies about different real life ideas as if they must somehow apply directly to the game. They do not. So talking about centrifugal force or gravity or moments of inertia or any real life physics is completely irrelevant. The only thing that matters relating to how a car drives is how PD modelled the physics, not real life physics.

As has been talked about in many, many different threads, some aspects of reality are modelled well in the game, some not so well, and some probably not at all. Some may or may not be backwards. You need to work within what the game gives you, not what you think it should be according to the real world.
Click to expand...

Nobody knows how PD models the physics, that's why we have to look to reality to understand what they're at least trying to accomplish. The effects of mass and inertia are easily demonstrated in the game, but you don't want to talk about them because the rest of the model isn't 100% perfect? Talk about throwing the baby out with the bathwater. If you can demonstate that a particular aspect doesn't conform to reality, fine, make an exception. But once you throw basic scientific principles out the window you're left tuning by voodoo. No thanks.
 
oppositelock
Nobody knows how PD models the physics, that's why we have to look to reality to understand what they're at least trying to accomplish. The effects of mass and inertia are easily demonstrated in the game, but you don't want to talk about them because the rest of the model isn't 100% perfect? Talk about throwing the baby out with the bathwater. If you can demonstate that a particular aspect doesn't conform to reality, fine, make an exception. But once you throw basic scientific principles out the window you're left tuning by voodoo. No thanks.
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I disagree.
I find many things inaccurate or non-existent, or even existent in GT5 vs IRL.

A prime example is downforce working at 0 MPH.
Weight is overrated in GT5 IMO also. Maybe that perception is based off the PP system, I'm not sure.
The one thing I know for certain, is since GT4, I've never had luck racing heavier cars, and why? IRL, heavier cars can often compete with lighter cars, in GT5 you just seem to gain so much through cornering and acceleration out of lower weight that the proportions are all screwed up.
I think it's primarily due to PD improperly modelling tire slip. Heavier cars typically have more acceleration grip IRL then light cars, but IN GT5, it seems the lighter cars still go like stink through low gears anyway.
Look at the Aston Martin V8 Vantage, heavy as hell, and all it wants to do is spin the rubber off the wheels like a dog shaking water off itself.

Either way, every car I've ever tested ran faster at the lowest weight possible, even unbalanced cars. I've never once improved a lap time by adding weight to a single car.
 
CSLACR
A prime example is downforce working at 0 MPH.
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How did you determine that? No sarcasm, just curious.

Weight is overrated in GT5 IMO also. Maybe that perception is based off the PP system, I'm not sure.
The one thing I know for certain, is since GT4, I've never had luck racing heavier cars, and why? IRL, heavier cars can often compete with lighter cars, in GT5 you just seem to gain so much through cornering and acceleration out of lower weight that the proportions are all screwed up.
I think it's primarily due to PD improperly modelling tire slip. Heavier cars typically have more acceleration grip IRL then light cars, but IN GT5, it seems the lighter cars still go like stink through low gears anyway.
Look at the Aston Martin V8 Vantage, heavy as hell, and all it wants to do is spin the rubber off the wheels like a dog shaking water off itself.

Either way, every car I've ever tested ran faster at the lowest weight possible, even unbalanced cars. I've never once improved a lap time by adding weight to a single car.
Click to expand...

I think your perception of REAL physics is what's off here. Light cars most certainly have a very serious handling advantage in real life, all else being equal. Anybody with any sort of actual seat time can tell you that. The fact that your lighter cars are faster in the game proves my point, not yours.
 
Why is it that when a race team; be it F1, Nascar, SCCA, autocrossers, remote controlled, etc. are allowed to remove weight down to a minimum weight level, why do you think they always remove as much as possible trying to skim to the limit? I remember listening to broadcasts of IRL and hearing Roger Penske tell his winning driver to pick up some extra rubber on the way back to the pits. That's purely to make minimum weights (and maybe a little ride height).
 

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