Could someone explain to me the effect of weight on a spring, and this translated in the car's handling characteristics?

If I had say a 400lb spring in front and 300lb spring rear, all other things about the suspension being equal.

I had 2 cars. With the same weight bias front and rear. Car A being 2200lbs Car B being 2600lbs.

Would Car B bounce around less than Car A? Would Car B feel smoother than Car A? Would Car B transfer more weight, resulting in more 'lean' around a corner?

Any knowledge would be great... I'm just learning.

 

It seems to me car B would be less bumpy, more smooth but it would transfer more weight around causing the car to sway more

 

Assuming both cars had the same distribution of weight between sprung and unsprung masses, car B would exhibit more body motion than car A, simply because there is more weight being moved around during suspension travel.

As far as ride quality, depending on how close the each car is to the ideal suspension frequency (for ride comfort) given those spring rates, either could be percieved as the harsher ride. Generally though, you'd want to err on the side of under-damped to preserve ride quality, so its more probably that car B would be provde the better ride.

 

I can answer this from experience. My Integra weighs a little under 300 lbs than my cousins civic and when I had the Apexi world sports on my car, it bounced arround and the bump stops were destroyed. They were also made for the ITR, but when we put them on my cousins civic, they were firm and solid, never bounced or bottomed out. The suspension was never adjusted, chainged or modified in any way from when it came off of my Integra to the point it was installed in the civic. Only the bump stops were replaced. I guess the weight of my car was too much for the suspension, but it worked great for the civic, eventhough it was used for a month. OH, I encountered a lot of wheel hop but my cousin did'nt.

 

wow, i just found a great program that will explain your situation and any typical mass-spring-damper system. you can play with the values, see what you get.

imagine a pogo stick with a mass (you), spring, and some kind of shock absorber taking away energy.

http://mathinsite.bmth.ac.uk/applet/msd/msd.html (wait for the applet to load)
(read this if you want to know the theory, but if you can understand whats its saying with the formulas, you probably dont need to read it anyway)

ignore the "forcing terms". it would be like what if the road was bumpy in a sinusoidal, or ramped or whatever road. a bit of a stretch and too complicated to bother with.

i will note that an example like this is different than vehicle dynamics because dampers are designed with different rebound and compression values, so it changes depending on the direction of motion, AND mass is divided by sprung and unsprung mass. but thats ok, this is simply a basic illustration of what a damper (shock absorber) does.

enjoy.

 

btw, the simple response to your question is that the car will (of course) simply feel "heavier". it will be slower to respond, lean a little more and overall a bit more sluggish. thats what adding more weight does to a car.

but you can play with the program if you want to know what changing everything else does too.

 

In this simple situation, the heavier car will make the same suspension seem softer/smoother...

fin.