Is heavier body the contributing factor in stability?

[Slayer]

bros and sis,

 

heard so many times that such and such make is heavier so it is more stable at high speed. I thought about it for a moment, it is not the only thing that make a car stable.

 

I just reason out with my limited physics knowledge. Please anyone chip in with your thoughts.

 

A heavier object need higher force to get the moving and once it is in motion, it take larger force to slow it down. for example, at Mini Cooper needs less braking power comparing with a Mercedes limosine in order to stop from 100km/h to 0. why? I think the answer is inertia.

 

Inertia can work in favour of the Merc in the scenario where by , eg. both car hit a brick the size of a fist. the mini has to fight very hard to stay on course. but the Merc could be not affected so much.

 

by telling the uninformed about stable at high speed , it is only tiny bit of the whole picture. F1 car 600+kg only, they are stable and agile.

 

The moral of the story is, there is a lot more that just weight to make a car stable at high speed. and weight is not neccesary a good thing. when the SE try to sell a heavy car, listen carefully.

 

weight -> drink more petrol, only contribute to the inertia and momentum which can be good or bad. depends on what that car is for. :)

stablility-> tyre grip, aerodynamics setup, suspension setup, centre of gravity..

 

just my thoughts.

[Icekitten]

I think braking is a different matter from stability altogether.

 

Stability is more about the ability to stay on course in motion, as you described. Braking is simply coming to a stop. In which case then, while a heavier weight is not solely responsible for better safety, it probably does contribute in a way.

[Stivo]

there are so much debate regarding these issues... guess there are two sides to the coins... still boils down to what u want in the car...

[Yeshe]

heavier is definitely more 'stable' at high speed. the word use is stability here, not safety. for those who travel to the north vis NSH will know that at speed excessive of 130km/h, depending on the car weight, the severity of the sway, especially when driving pass heavy vehicles at that speed.

[Pisces69]

I guess the heavier car got a stiffer body which makes it flex less during cornering & also when going straight, the weight helps keep it moving in that direction as when going over bumps too (Inertia at work).

 

But cornering & quick handling is affected by a heavier weight cos now u also got centrifugal force & inertia at work again.

 

So u can have a light car that handles well if it was designed & built well. Likewise u can also have a heavy car that handles badly.

 

Now cars r built lighter to improve handling & reduce FC but the better cars r strengthened in all the right places to give it strength & rigidity.

 

But weight does play a part in an accident. U see so many solid cars badly crushed & drivers/passengers killed or badly injured when they have a high speed head on with a truck or lorry. The cars with airbags generally save more lives cos that's one of the best safety devices on a car nowadays.

[Icekitten]

Sorry my mistake..I meant heavier weight contributes to stability not safety.

[Chevycavy]

For me it's a YES.

 

My car weighs abt 1 ton and during hard cornerings I get the feeling my car is flying off. But after I did soundproofing of my 4drs and car boot I found that taking the same corners my car feels more planted on the ground. I no longer get the "flying off" feeling. This is with same tires.

[Pisces69]

Maybe the quieter interior gives u the impression your car is more stable?

[Russ]

Weight plays a small part but it is suspension tuning for the most part = the continental car makers are much better at this than the Japs.

[Picanto]

take a look at those F1 cars. weight is light, but stability still there.

[Icekitten]

To be honest I think F1 cars shouldn't be taken into consideration as fair comparison as they are specially manufactured to race only and nothing else. Plus there is only 1 driver.

 

In short there is nothing really practical in the design of F1 cars that can be used in regular passenger vehicles in normal road conditions.

[Humsuplou]

aiyah ... just try to do 180 in a Kelisa and then do the same in a merc ...

[Dwoon]

My experience on high speed stability is on the height of the car. When its high, it allows the air to go under and lift the car making it very light and floaty.

 

I've lowered the car abit on the front only, by 1 inch. (rear is stock height). Sama drag car setup but not by intention.

 

You can't imagine what wonders this does. From instability/floaty feeling at 160km/h... I don't even get it now at 220- 230km/h. (well maybe some lah at that high speed, but not even close to what I experienced on stock height running 160km/h).

[Mingsect]

those f1 car went thru wind tunnel tests .

 

their front and rear spoiler are then config/ adjusted and measured for max downforce in highspeed , to press the machine down.. for max grip ..

 

so cannot compare

[Icetrap]

  Quote

A heavier object need higher force to get the moving and once it is in motion, it take larger force to slow it down. for example, at Mini Cooper needs less braking power comparing with a Mercedes limosine in order to stop from 100km/h to 0. why? I think the answer is inertia.

 

True. That's why Mercs and volvos are more stable at higher speed. On the NS highway the kind of the roads are not EVOs and WRX but thoses Merc 500 Series BMW 7 series and above.

 

However they are only good for high speed stability. Cornering wise, they are less agile. The weight of the car, although stable will push them off course. A light car will be more agile in such a situation.

[Yeshe]

  Quote

take a look at those F1 cars. weight is light, but stability still there.

 

those F1 cars are light BUT the design is in such a way where the center of gravity is VERY low. the design also make use of air pressure to push the car down onto the track for better grip and control at high speed. however, if they come with slight collision, they will 'fly'.

[Slayer]

for high speed stability, it is more meaningful if top it off with safety in mind for us day to day commuter .

 

for high speed stability and safety.. we don't want the car to be too light + bad aerodynamics design. like what hamsaplou mentioned. kelisa doing a 180. that could tip over and fly off like a kite.

 

ok, let see, for a good handling cruiser to be comfortable at 200km/h , what it need:

- decent weight like 1.5 to 2tnonne?

- a 'good' suspension. (what is good? )

- not too high Center of gravity. about 1.5 ft from the ground?

- tyres with good grip. (again, what is good? )

- aerodynamics ie. undercarrriage air flow that wont lift the car. good enough downforce ..

- chasis strong.

[Quantum]

I don't know whether you noticed the newspaper report(forgot the date), a Singapore indian guy drove a 'light' car back from Malaysia, unfortunately he met flooding, due to the car too 'light', he lost his wife and daughter forever