▁increased ▁power ▁for ▁p umps ▁or ▁fr iction ▁from ▁se als . ▁ ▁When ▁a ▁roll er ▁or ▁ball ▁is ▁heavily ▁loaded , ▁fluid ▁bear ings ▁have ▁clear ances ▁that ▁change ▁less ▁under ▁load ▁( are ▁" st iffer ") ▁than ▁mechanical ▁bear ings . ▁ ▁It ▁might ▁seem ▁that ▁bearing ▁st iff ness , ▁as ▁with ▁maximum ▁design ▁load , ▁would ▁be ▁a ▁simple ▁function ▁of ▁average ▁fluid ▁pressure ▁and ▁the ▁bearing ▁surface ▁area . ▁ ▁In ▁practice , ▁when ▁bearing ▁surfaces ▁are ▁pressed ▁together , ▁the ▁fluid ▁out flow ▁is ▁con str icted . ▁This ▁significantly ▁increases ▁the ▁pressure ▁of ▁the ▁fluid ▁between ▁the ▁bearing ▁faces . ▁ ▁As ▁fluid ▁bearing ▁faces ▁can ▁be ▁compar atively ▁larger ▁than ▁rolling ▁surfaces , ▁even ▁small ▁fluid ▁pressure ▁differences ▁cause ▁large ▁rest oring ▁forces , ▁maintain ing ▁the ▁gap . ▁ ▁However , ▁in ▁light ly ▁loaded ▁bear ings , ▁such ▁as ▁disk ▁drives , ▁the ▁typical ▁ball ▁bearing ▁st iff ness es ▁are ▁~ 1 0 ^ 7 ▁M N / m . ▁ ▁Compar able ▁fluid ▁bear ings ▁have ▁st iff ness ▁of ▁~ 1 0 ^ 6 ▁M N / m . ▁Because ▁of ▁this , ▁some ▁fluid ▁bear ings , ▁particularly ▁hydro static ▁bear ings , ▁are ▁deliber ately ▁designed ▁to ▁pre - load ▁the ▁bearing ▁to ▁increase ▁the ▁st iff ness . ▁ ▁Fl uid ▁bear ings ▁often ▁inher ently ▁add ▁significant ▁d amp ing . ▁This ▁helps ▁at ten uate ▁reson ances ▁at ▁the ▁gy ro scop ic