Why is your car uncomfortable? What happens to make your suspension uncomfortable?
When the wheel of the car goes over a bump and the spring and damper cannot compress fast enough to absorb the bump, so some of the movement is transferred in the car. When the force of the bump is transferred into the body of the car, this is when you feel the bump.
The best way, by far, to make a car more comfortable is to soften the dampers. The dampers are what are restricting how fast the suspension can absorb bumps.
If you want to make your car’s suspension more comfortable, fit softer dampers. However, the chances of finding dampers that are softer than the factory items is remote, so the next best alternative would be to find adjustable shock absorbers/dampers which have a good range of adjustment.
The next step after dampers would be to fit lighter wheels.
The long answer…
I have used Spax CSX adjustable dampers. They are excellent. The difference between their softest setting and their hardest setting is complete eg the softest setting offers little damping, the car is almost bouncing on the springs while the stiffest setting makes the suspension rock hard.
Using relatively stiff, linear springs on these CSX dampers the ride could be changed from softer than stock to rock hard just by changing the stiffness of the damper and without changing the springs.
The comfort of the ride is transformed without changing the springs.
The other side of the coin. What happens when you change the springs?
If you have ever changed your stock springs for a set of sport springs (without changing the shock absorbers/dampers) you will know that the effect on ride comfort is minimal.
Where sports springs like H&R and Eibach make a difference is in the control of the body, there is less roll and pitch. More stability in all conditions.
What is the difference between springs and dampers?
Springs do two things.
They support the weight of the car ie stop it from touching the ground
And secondly the support the car in roll and pitch. Stiffer springs, less roll and pitch, softer springs, more roll and pitch (cornering, braking, acceleration).
Dampers/shock absorbers control the speed the spring compresses and expands. The dampers job is to damp the movement of the spring. In gradual conditions eg roll and pitch, the damper does not exert a strong resistance to movement of the suspension.
However over bumps, the suspension is trying compress quickly, this is when the damper becomes stiff
An analogy – A bicycle pump
The slower you compress the pump the less the resistance you get, the faster you try to compress the pump the more resistance you get. The damper/shock absorber works in the same way as the bicycle pump.
When you go over a bump the spring and damper are forced to compress quickly, hard dampers will make the ride hard because they won’t allow the suspension to compress enough to absorb the bump.
This is why the shock absorbers play a much bigger role in ride comfort than springs. It is the damper than controls how far and how fast the suspension can compress and expand.
The Perfect Suspension
For the best performance in pitch and roll, the hardest spring possible gives the most control, while at the same time using the softest possible damper that will stop the spring from oscillating uncontrollably.
But like most things is car design there are compromises everywhere.
Because the hard springs will logically only compress a small amount in pitch and roll, the speed the spring compresses will also be slow because the spring is only covering a short distance. For the damper to be effective in slow movements it has to be stiff (see the bicycle pump example above)
This creates a problem with bumps.
Bumps will logically move the suspension more than pitch and roll and bumps will move the suspension faster than pitch and roll.
This is a problem because we have fitted a stiff set of dampers to suit our stiff springs. The damper will not want, or not be able to compress enough to absorb the bump.
When the shock absorber cannot compress fast enough the shock is going to get transferred to the shell/body of the car and this is where the discomfort really comes from. Bumps being transferred in chassis instead of being dealt with by the suspension.
Hard springs force use to use hard dampers which makes the ride uncomfortable.
At the opposite end of the spectrum. Soft Springs = Soft Dampers
Soft springs have big travel, which means higher compression speeds. For the suspension to have the full range of movement we also need soft dampers.
This is the compromise.
We want good handling which means stiff springs which dictates the use of stiff dampers
But we also want good ride which means soft dampers which dictates the use of soft springs.
Spring Damper Matrix
Soft springs and dampers give good comfort but no performance
Soft dampers and hard springs give good performance and good comfort
Hard dampers and soft springs give no performance and no comfort
Hard dampers and hard springs give performance and no comfort
|Soft Dampers||Hard Dampers|
How to get around this paradox?
When can never eliminate the compromises completely but we can improve performance by using better quality materials, specifically
Better spring material
Lighter Wheels – Better Ride
Lighter wheels improve ride comfort in a number of ways. A lighter wheel is moved more easily, it takes less force to move it up or down.
Because there is less force involved in the light wheel moving up and down as it goes over bumps we can back off the hardness of the dampers because the damper is controlling less mass.
A lighter wheel allows the fitting of even softer dampers which improves ride even more.
There is no compromise to fitting light wheels, except the higher price.
Uprated Progressive Springs – Better Performance
Uprated (over stock) progressive springs are stiffer in spring rate when they are compressed, giving better pitch and roll control.
Because we use the stock dampers with these springs (H&R, Eibach etc) ride comfort is barely effected.
There is very little compromise using uprated springs.
By using better spring material we can have springs with a greater range of progressivity. ie the soft part of the spring travel can be softer and the stiff part of the spring travel range can be stiffer.
We can use better quality materials (read lighter) in the suspension eg the suspension arms . Lighter suspension arms give us the same benefits as lighter wheels.
Trying to get the best ride and best handling is a compromise.
The most effective way to make a car’s suspension more comfortable is to make the dampers softer. Using lighter wheels and suspension components allows us to use even softer dampers, giving an even comfier ride with relatively little effect on performance.
Fitting uprated springs which use better materials gives us better performance in roll and pitch with relatively little effect on ride.
Change to softer dampers for better ride
Change to stiffer springs for better roll and pitch performance.
Change springs and damper for optimum performance with worse ride comfort
For the worst ride comfort and little to zero performance improvement, fit stiffer dampers with the stock springs. You get the worst off all worlds.