50/50 weight distribution

Is it a myth Veeky Forums?

Other urls found in this thread:

automotivethinker.com/chassis/stop-and-weight-a-5050-weight-distribution-is-not-optimal/
supercars.net/blog/1993-nissan-skyline-gt-r-group-a/
gtr.co.uk/forum/89582-calsonic-group-suspension-set-up-anyone-know-what.html
bing.com/videos/search?q=mazda 50/50 video&view=detail&mid=ECCC50E61BFF907F1AAFECCC50E61BFF907F1AAF&FORM=VIRE
twitter.com/SFWRedditVideos

It's a meme.

You want more weight over the front axle for maximum rotation potential.

>go to supermarket
>grab a shopping cart
>grab a big bag of dog food or something similarly heavy
>put it as close to the back of the cart as possible
>round a corner with it
>put bag of dog food to very front of cart
>make same corner

Weight distrubution isn't a meme

physics and simulation guy here

Sort of.

The maximum cornering potential is when the lateral forces are used 100%; which basically just boils down to the mass pushing you outwards matching the grip pulling you inwards.

Assuming no downforce, and a constant speed, a 50:50 weight distribution will work perfectly when you have the same fromt and rear tyre size and contact patch. This is just basic physics.

If you increase the rear grip from that state, the forces pulling you inward are behind the center of the car, while the force pushing you out are still at the center, hence you'll understeer. Center of grip is behind center of mass = understeer.

(p1)

That's not to say that 50:50 weight is needed. Merely that the forces have to be balanced. So if you've got 70% rear weight distribution, you need 70% of the cornering force to be from the rear wheels.

One example of this are the prototype cars - since they've got a much higher rear weight distribution that normal, they require bigger rears and more rear DF for cornering.

>p2

p3

The other end of the spectrum is front-biased design. Nor really seen on cars too much, but rather planes. Nobody's ever going to give something like the spitfire shit for 'handling poorly' despite it's cg being so close to the nose (think about 25% from the front of the wing). This is because the main force (lift) is very close to the center of mass. If you moved the front wing back 1m, it would lawndart (understeer) and if you moved the wing forward 1m it would oversteer (like an arrow fired feather-first).

pic sorta related

p4

For cars you have other concerns.

Wheels and tyres - if you have all 4 the same size you can rotate them to max tyre life. Favors ~50:50 weight distribution

Idiot drivers - understeer is generally safer for the average pleb. favors a slight 60:40 bias with equal wheel sizes.

Maximum tyre size - in racing there will be a max tyre size. FIA don't give a fuck, ever, so it's best to find the biggest tyres possible allowable by the rules, then build the aero and weight around that. This kills the FWD Nismo.

Underfloor aero - things like front splitters and diffusers only work when there's sufficient volume underneath the car that can exit cleanly. So basically, the gap between the tyres at each axle. This also kills the Nismo FWD, because they don't have the volume between the front wheels to get that much air through. This would also kill the Flintstone-mobile's chance of generating any ground effect downforce, RIP Fred & Wilma on any med-speed corners.

Pic sorta related, could really use more space between the rears, but because weight distribution and hence tyre requirements, can't run a diffuser as effective as would be ideal.

intelligent informative poster writing at a level that is understandable to people with only basic knowledge of science

i didnt think those existed on Veeky Forums

you're be surprised. I was the antithesis to hakuna miata.

actually (p5) one thing I forgot is you can generate a better moment (leverage) by extending the distance between the cg and the turning wheels.

In the Spitfire, this is the distance from the cg (front of the main wing) to the elevator (flat tail plane). In a car, the only thing I can think of is a MR or RR car and the front wheels, and the result (assuming a balanced tyre/aero setup) should be very responsive turning and steering feel. Of course, since manufacturers like to have that efxtra rear grip for safety casuls, this is usually at best un-noticeable, and at worst the steering is too light and unweighted.

It's perfect if you don't wanna fall from a balancing platform that's only purpose is to make non 50:50 car fall of it.

Interdasting.
What about actual mid-engined ww2 fighter? Bell p39 airacobra.

If you're in a porsche, just drive forward a bit. if a camaro, reverse a bit, and both will balance as long as the cg is over the fulcrum...

automotivethinker.com/chassis/stop-and-weight-a-5050-weight-distribution-is-not-optimal/

50/50 is a myth.

This only proved the concept of weight centralisation, not distribution over the axles, since you're not using the weight to create tractable power.

because the cobras were mid-engined, the distance between the cg (again, think 25% from the front of the wing) and the elevator means that a spitfire should 'bite' harder on initial pitch because the spit has better leverage (longer 'arm' to the tail).

The advantages the cobras would have are:
engine can't be hit when retards try to use it in head-ons
engine might not be hit because it's in an unusual place
can mount cannons and guns in nose for better accuracy (guns on wings = firing with your arm out to the side)
better speed (smoother nose, doesn'thave to fit big engine up front in blunt cowling)

Also, lower polar moment. Because all the mass is located in the middle, it's less like a set of dumbbells, so less momentum when rotating.

Some problems were:
they had to increase the size of the tail in later models, because of the moment problem. Think of it like this, the spitfire's tailplane might generate 100N of force at 6m aft of the cg, and to match that with a cobra's 3m you need 200N, so twice the force = double sized tailplane = more drag

You're also forgetting forward acceleration. Sure, cornering force is absolutely ideal when matched to F/R weight distribution, but forward acceleration in any car is best with drive wheels at the rear, and a slight weight bias there as well. Same goes for brake: removing weight off the front unloads the front brakes (which doa majority of the work), and allows the rears to work, making for more efficient braking.

4 equal sized tires does not compute with average car packaging. For any given car width, a ideal (as large as possible) front wheel will always have to turn, so it'll always have to be narrower than the maximum of the rear wheel.

Yep, I deliberately didn't go into other forces much, I only talked about constant-sate cornering.

When you add in acceleration, braking and turn-in or power-out, you have 999999 more possibilited and variables like cog height, drive wheels, turning wheels (4ws like the 918), and roll centers to fuck with things.

As for the second part, not always (though you worded it weird). if your fronts are 300mm and your rears only 200mm, you've got a 60:40 grip distribution, so if the car has a 70:30 weight distribution (old Audi S4 maybe) then it'll understeer despite the fronts being 50% more grippy than the rears.

What I meant is:

Front wheels have to steer. Assuming a car is equally wide front and rear, and assuming the hubs are equally far from the center of the car, then a front wheel can never be as large, or larger than the maximum size of the rear wheel. it'll always be smaller, because it has to turn and steer the car, so it'd hit the fenders before the rears would (since the latter don't turn).

Maybe. I'm still not getting something I think. There could be some difference in fender size or track, perhaps.

There haven't really been many cars released with bigger fronts though. Audi comes to mind (S1? S3? something like that), and there was probably one of the shitty american 90's cars with a FWD V8 that had bigger fronts than rears (ORIGINAL IDEA DO NO STEAL NISMO PLS)

I get what you mean but there are ways around this such as ATTESA E-TS combined with super HiCAS
also torque and brake vectoring can be used to make sharper turns
or passive rear steering systems like the weissach axle

supercars.net/blog/1993-nissan-skyline-gt-r-group-a/
they chose the engine capacity to fit in a weight class
and 4wd to skirt the 10" max tire width mandated by the engine size
later skylines has 11" tires and a larger engine

gtr.co.uk/forum/89582-calsonic-group-suspension-set-up-anyone-know-what.html
and the suspension was just made up as they go along apparently

Someone screen cap this thread

What the fuck is going on here

finally something actually useful instead of that link to that retarded article that's boils down to hurr because racing cars have rear bias it means it's superior without actually explaining why they use such weight distribution

This is the dumbest thing ive read today

this is why f1 cars are rear weight biased right?

Holy shit stop spreading misinformation. I have a theoretical degree in physics and you're acting all smart as if you knew

What happens if a car has more forces of grip acting on the car than there are forces of weight pulling outward?

Also what effects do air moving under and around the car have on weight and grip balance?

>theoretical degree in physics

You can't ruse me Mr. Ruseman.

retard

jesus christ that hood

it would stop, but since that would be caused by air moving over the car, its going to drop along with the speed.

active downforce shit like fans cant exert enough force to stop it.

bing.com/videos/search?q=mazda 50/50 video&view=detail&mid=ECCC50E61BFF907F1AAFECCC50E61BFF907F1AAF&FORM=VIRE

...

doesn't the weight of the driver fuck it up

Yes it's a meme, but a relevant meme
Rear bias is king for performance
50/50 is for driver feels and controlability

Which wheels turn on a kart and where are you standing when turning it? Idiot it's not a valid comparison

He's talking about our beloved civics

humans are not 50/50 and they have been alive for hundreds of years

With good posture and normal weight distribution you are. When you hunch forward you put mad stress on your spine

fun fact: those galactically huge70's El-dogs are front wheel drive.

are you seriously comparing the weight and balance considerations of an aircraft to a car?
abandon the thread guys, it can only get dumber from here

50/50 is perfect, but not obtainable during hard acceleration or braking unless you have some sort of heavy pendulum in the chassis...lol...this is why LIGHT WEIGHT and a 50/50 balance is better for the BEST handling.

>replying to a trip called SHITPOST GUY

I've heard some cars like the Cappuccino are 50/50 when the seats are occupied, I'm not sure what other cars this might apply to

>rotation potential

make sure you check your headlight fluid too before a long trip

mazda made the fd so seats are directly above center of gravity and when people get in the weight distribution remains the same, a properly balanced car
meanwhile barges like the corvette and viper the manufacturers just cram seats as far back as possible hoping the obese occupants will offset the boat anchor engine up front

this, the bait is so obvious

Just reverts to simply physics; if the force towards the center of the turning arc exceeds the force outwards, the radius will decrease. Like a nascar going slow on a highly banked corner.

wat
the power of physics transcends you, evidently.
>wat racing and aerospace technologies, inc
>The company the puts a LS1 in a Cessna

you think I'm smart? you should see what people do with Assetto Corsa's roll centers.

spoiler alert - cars need a driver to work, but not a full tank of fuel. An easy way to get a good estimate for the cg is to look at the fuel tank; it'll usually be over the cg so that doesn't change as it gets burnt off.

not a meme.


But 40 front 60 rear its optimal for tracking.

Believe it or not, the viper drives as a rear engine car.
I weight about 60kg and drove one for about 2 hours in a mountain road.