shock fade

SHOCK FADE

Definition: A condition where loss of dampening action occurs because of fluid foaming inside a shock absorber. The rapid oscillations of the piston moving through the fluid churns it into foam, which reduces the amount of resistance encountered by the piston. This causes the dampening action to fade, resulting in loss of control, excessive suspension travel and reduced handling. Pressurizing the fluid chamber inside the shock with a gas charge can minimize foaming and prevent fade.

Heat is also a contributor to the foaming that causes the fade resie will add more voulme to the shock giving it the area for oil and air to seprate beter and more oil less air in the shoch equals less foamy oil.

when the oil in your shock gets worked by the moving piston it is converting this movement into heat.

heat is absorbed by the oil, and transfered to the body and to an extent the gas in the resivoir.

the gas has the purpose of pressureizing the oil, we do this to raise the temp needed to boil or create gas in the oil itself.
Oil NOT presureized will foam instantly when the piston travels through it.

This fade occurs as the oil is heated, broken down from contamination /ie. ice or water injestion past the seals and the wearing of the body from piston movment.

When we let the shock rest, the temp drops, the oil de gasses to a point and the shock feels different, not better, not right just different.

Oil in the DOO shocks is fish oil based, NOT a high quality synthetic or organic.
It breaks down in hours and is contaminated from the intial use, I hate to say break in, as there is nothing to break in, just contaminates from the machineing process...

change the oil to a quality synthetic 5 weight, 10 or thicker will cause even faster breakdown as the cold will make it to viscous to properly pass thru the stack and shear the oil molecules casuing faoming at low temps( cavitating).

KYB sled shocks also run at 300 psi nitrogen pressure, lower than that and the cold will cause leaks at the o rings.


Gus

Same device, different applications and results.
the Bladder type is for warm weather use, they run lower pressures and have slightly less frictional drag. ( debateable ).

When you feel fade in the shock its already to late, need a service done and then evaluate your valving and spring selection.

fade is unavoidable when under sprung, under valved and overused..LOl


Gus
BSP

the larger volume of iol in the res shock will make it out work the no res shock before the heat soak gets to the point of fade.

If you have not had the oil changed in either type and they are a season old.
You will see fade in minutes of ( USE ).
slow riding, or hard riding. does not matter, dirty contaminated oil is mush .

more oftern than not, the nitrogen weeps past the piston and gases the oil from a hard hit on a cold shock. once its happened its over, rebuild .


gus