Hi Lo & Soft Hard Coilovers
20 March 2004
First a setup needs to be introduced: -
The set shown above is a TRUE high low and soft hard adjustable. This name / term is however incomplete and cause many confusion amongst consumers and mislead many consumers to buy the wrong thing.
The complete definition should be: -
RIDE height high low adjustable as well as ABSORBER's rate soft hard adjustability.
Now after reading the above, I'm sure everyone understands what it can do and what it cannot. By the way, these are coil over absorbers and they are simply known as coilovers.
Absorber is easiest to explain, so here it goes. If the absorber have a knob for it to turn then it is soft hard adjustable. If the absorber has got no knobs to turn then it is not soft hard adjustable.
Buyers please be careful, because not all adjustable absorbers have adjustability for downward stroke and upward stroke together.
The cheap ones only have downwards stroke adjustability, but they won't tell you that, because you never ask.
Or the cheap ones only have upwards stroke adjustability, but they won't tell you that, because you never ask.
Or they have both, which is very good, but ...
The good ones have independent downward stroke adjustability as well as upward stroke adjustability, so prepare to pay a very high price for it.
Many have between 8 steps to 16 steps. Some have as much as 40 steps.
Say, are you a racer tuner, do you need all this? I know I don't.
Now comes the COIL part. Be careful here, it's very tricky. You've got your pop corn ready? :)
Suspension theory says never to compress a coil when installing onto a vehicle. The set shown above can meet this requirement. In fact all other coilovers can be SETUP not to compress the coil when installing.
However ................ after installation, some times it is found that the car's RIDE height is TOO LOW and needs to be raised one inch higher or two inches higher.
The fake hi lo adjustable coilovers cannot raise the car. The installer is then forced to use the bottom coil seat's plate to compress the coil upwards in order to raise the car height. In this case say one inch.
From the outside look. It solved the problem. However upon closer inspection, it is revealed that the suspension has lost one inch of the coil's softest travel, as well as one inch of the absorber's least damping travel. It is no wonder why so many coilovers' users complaint that it is not comfortable. For details please see Side Notes 3.
Except for TiTAN, which is very performance yet comfortable.
Now in order to solve this RIDE height problem. Some other coilovers manufacturer smartly custom make another gear thread at the bottom of the coilovers. They add another locking plate and finally add the actual holding mechanism / knuckle.
When the car is too low, the locking plate is released and the holding mechanism / knuckle is moved downwards to raise the car's height. This is a very good solution and does not compress the coil initially.
This is ONE of the TRUE RIDE height high low adjustable. The other method to achieve TRUE RIDE height high low adjustable is as used by TiTAN.
TiTAN have real suspension fundamentals knowledge hence upon "CUSTOM" building "EACH" coilovers set for "EACH" individual customer, the car's original coil specification is measured using a compression machine and the earth gravity's force (psi/inch) value will be known and hence applied to the "NEW" coilovers and the ride height will be known, as well as absorber's stroke travel etc. Therefore the coilover will be perfect for that particular car and for that particular customer's requirement.
i.e. If the customer says one inch gap between wheel and mud-guard, then TiTAN will be able to achieve it without needing to use trial and error method. TiTAN always gets it right the first time. They are just too good in these stuff.
Below, a picture zooming on the RIDE height adjustable part.
Purple color words - 2nd gear thread to adjust height for high or low without compressing the coil or setting it too loose. When set too loose, helper spring is required to hold coil in place when jumping.
Now that you've understood the true ride height issue, please just let me enlighten you on the "TOO HIGH" issue.
What happens when the coilovers is too high? The installer will release the coil seat's plate and turn it downwards. In this case one inch.
But the absorber cannot come down one inch. It simply has to stick up because it was "MEANT" to be. Oh dear. Well for a "don't care" installer - it's OK one, nothing will happen, it is like that one............ you get the idea.
The ill effect of this is when the car JUMPS and the wheel (unsprung weight) is pushed downwards by the coil's expanding properties as well as earth's gravity and the absorber's natural behavior to extend to it's longest length.
It will come to a point where the coil is "FREE FLOATING" and have a "ONE" inch gap between the bottom coil's seat and top coil's cover.
Oh my god, the coil is loose and free moving. When the car falls back down, do you think the coil will still be centered between the bottom coil's seat and top coil's cover?
SURELY NOT. It will be clamped at an angle and jumps / bounce a few more times before settling down to the original coil's holder.
By the time, many things / items is forcefully scratched, injured, coilovers thread damaged, coil itself dented somewhat, the absorber's stroke may bent somewhat. Prolong use will kill the setup all together.
So, how to solve this? Installer will ADD "HELPER SPRING" to hold the loose coil in place. Hahahahhahh more $$$$ wasted, more $$$$ made by the installer :) ahhahahahaah
See the top thiny little coils = helper spring.
So, now that the helper spring have solved the problem, it is all OK.
By doing this, when the coilovers are installed onto the vehicle. The first one inch drop of the absorber is purely the car's weight without the push up assistance of the TRUE coil, but instead is helped by the thiny tiny helper spring. Then the car pushes lower into the coil's strength zone and settle.
Imagine the car JUMPS again ................ :) heheheheheh
The wheel (unsprung weight) will be pushed down
1) first by the coil's expanding strength + earth's gravity + absorber's expanding strength
Then when the coil's expansion stroke / travel completes ...... the wheel (unsprung weight) will continue to be pushed down by
2) earth's gravity + absorber's expanding power + thiny tiny helper spring
Won't you feel the changes of energy too sudden? Do coilovers users using helper spring feels this?
So, no big deal, why the fuss?
Now imagine the car reach the highest point of jump and is falling down........ the moment the wheel touch the floor, the absorber will set into motion to slow down the RATE of DESCEND.
1) absorber's first one inch stroke to slow rate of descend + thiny tiny helper spring.
Is there anything else to help slow down the rate of descend?
then suddenly the absorber finished it's first one inch travel, lost the thiny tiny helper spring's support of say 0.01 kg/mm
and finally move into the coil's region............
2) absorber + coil to slow rate of descend.
Do you feel PAIN now?
It's exactly like we as human simply jump onto a coil on the floor. Too sudden.
This is another reason why helper spring users complain the setup is not comfortable and always HARD.
TiTAN never uses helper spring, never compress coil. When the car jumps and the wheels goes down, the rate of change is linear and smooth. No sudden changes. When the car reached it's maximum height and falls back down, BOTH absorber and coil ACTs as one to slow down rate of descend. User does not feel SUDDEN changes, hence no pain, hence comfortable.
So, what is the conclusion for today?
Helper Spring solve one problem just to add another.
Get the fundamentals right and you'll be rewarded by proper handling, performance and not sacrificing comfort.
Go get TiTAN. They are the only one who does it the fundamental way.
If you know any other brand / installer who gets is right using fundamentals, please let me know, so that readers get to choose another brand.
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