consider to reduce unsprung weight in order to improve comfort level

[peter_302]

Assume sprung weight(300kg)/unsprung weight(50kg) = 6, I checked each genesis front rotors is 10.3kg, I suppose to change front rotors from 10.3kg to 8.7kg , the rate is 300kg/46.8 = 6.4(actual maybe higher because I cannot found sprung weight of genesis), so it means suspension could promote 7% performance for up and down movement, it could better interact with rough surface.

My question is should I change springs and shock rate in order to match the
changed rotors? If not, could I change rotor alone has better dynamic response for improve ride comfort level

I think this have less cost to got better suspension performance, please help to give advise, thanks a lot

 

[Rey]

I think any material reduction in unsprung weight will cause the suspension to react more smoothly and in closer compliance with road surfaces. My advice is first to reduce the weight, and then worry or not worry about whether or not your springs/shocks are optimum. Presently, there is virtually nothing available in the aftermarket for springs, shocks and sway bars. You would have to fabricate your application using off-the-shelf materials. This will require some engineering calculations, which are not readily available either.

I think one of the most elusive and forgotten subjects on unsprung weight is Mass. Mass of any object is measure by the weight of the object times the square of the speed. A seemingly small weight reduction in a spinning wheel assembly has a huge reduction in mass. The greater the mass of an object, the more resistant to change in movement, i.e. suspension compliance.

I have seen many auto owners complain about the ride degradation after installing huge aftermarket wheels. In their complaints they rarely talk about comparative wheel weights. A heavier wheel assembly will not react to a road bump like a lighter assembly. The lighter assembly can roll over the bump while the heavier assembly resists any change, resulting in harshness.

 

[Gambler]

...
I think one of the most elusive and forgotten subjects on unsprung weight is Mass. Mass of any object is measure by the weight of the object times the square of the speed. A seemingly small weight reduction in a spinning wheel assembly has a huge reduction in mass. The greater the mass of an object, the more resistant to change in movement, i.e. suspension compliance.
...

This paragraph is incorrect, you are confusing mass and weight (and force for that matter).

 

[Seattle Genesis]

I think I left the bathroom light on when I went to work this morning. LOL

 

[peter_302]

I think any material reduction in unsprung weight will cause the suspension to react more smoothly and in closer compliance with road surfaces. My advice is first to reduce the weight, and then worry or not worry about whether or not your springs/shocks are optimum. Presently, there is virtually nothing available in the aftermarket for springs, shocks and sway bars. You would have to fabricate your application using off-the-shelf materials. This will require some engineering calculations, which are not readily available either.

I think one of the most elusive and forgotten subjects on unsprung weight is Mass. Mass of any object is measure by the weight of the object times the square of the speed. A seemingly small weight reduction in a spinning wheel assembly has a huge reduction in mass. The greater the mass of an object, the more resistant to change in movement, i.e. suspension compliance.

I have seen many auto owners complain about the ride degradation after installing huge aftermarket wheels. In their complaints they rarely talk about comparative wheel weights. A heavier wheel assembly will not react to a road bump like a lighter assembly. The lighter assembly can roll over the bump while the heavier assembly resists any change, resulting in harshness.

Yes, I have read lot of thread who complain about ride quality and want to aftermarket springs or covers. I feel most bumps are absorbed by springs and the shock has limit response, so I want to reduce unsprung weight in order to promote utilization of the shock. First I could get down to rotors, and my genesis 3.3 has the same rotor with U.S. 3.8 version , some parameters as below:
Size: 321X28T
Weight: 10.3KG
Vent: 9.2mm

If change it to AP5200, nearly same size(330mm) it weight 5.7Kg, so it's mean that I could reduce unsprung weight 4.6kG on each front suspension, calculate that 4.6*2=9.2KG, the sound said it could reduce 92KG on sprung weight

 

[Mark_888]

I don't know about the Asian version of Genesis, but for US version in 2012 the problem was addressed by using softer springs and slightly firmer shocks. If the 2012 version in Asia made similar changes, you could just swap out the springs and shocks with those from 2012 model.

 

[peter_302]

I don't know about the Asian version of Genesis, but for US version in 2012 the problem was addressed by using softer springs and slightly firmer shocks. If the 2012 version in Asia made similar changes, you could just swap out the springs and shocks with those from 2012 model.

I'm not going to replace shock and springs for performance. I just ont sure whether I change the rate of sprung weight/unsprung weight could balance the performance and comfort, or whether changes could reduce unwanted body motion and vibration felt


share genesis suspension with you:
front:

rear:

 

[mcginnpm]

Mass of any object is measure[d] by the weight of the object times the square of the speed. A seemingly small weight reduction in a spinning wheel assembly has a huge reduction in mass.

I think you meant that weight (i.e., force) equals mass times gravity (i.e., acceleration).

F = ma or W = mg.

Mass is a measure of inertia, or resistance to change in velocity. The mass of a given physical object (such as rotors, wheels, suspension parts, etc.) does not change, no matter how fast you spin them, whereas the force they impart is proportional to their acceleration.

 

[Mark_888]

I'm not going to replace shock and springs for performance. I just ont sure whether I change the rate of sprung weight/unsprung weight could balance the performance and comfort, or whether changes could reduce unwanted body motion and vibration felt

The suggestion to use 2012 suspension parts on a prior year Genesis model was not for performance, but to increase comfort. This subject has been discussed many times in this forum, so I am not going to get into the details again here.

The pictures you posted appear to be the KDM version with optional air suspension, or if not, they certainly don't look much like the US suspension system (especially in the rear).