bar , ▁or ▁just ▁simply ▁anything ▁that ▁is ▁possible ▁enough ▁to ▁gr ind ▁on ▁it . ▁ ▁Property ▁damage ▁Gr inding ▁is ▁dam aging ▁to ▁materials ▁which ▁are ▁not ▁hard ened ▁for ▁the ▁specific ▁purpose ▁of ▁the ▁sport , ▁as ▁may ▁be ▁found ▁in ▁a ▁sk ate ▁park . ▁The ▁tr uck s ▁are ▁composed ▁of ▁a ▁hard ▁metal ▁without ▁lub ric ant ▁or ▁bear ings ▁on ▁the ▁gr inding ▁surface , ▁so ▁they ▁literally ▁do ▁gr ind ▁on ▁the ▁objects ▁they ▁slide ▁across . ▁Gr inding ▁can ▁strip ▁paint ▁off ▁of ▁steel ▁and ▁wear ▁down ▁the ▁edges ▁of ▁concrete , ▁stone , ▁al umin um , ▁and ▁wood ▁building ▁materials . ▁A ffect ed ▁business ▁own ers ▁and ▁government ▁buildings ▁have ▁put ▁up ▁anti - sk ate ▁devices ▁as ▁a ▁d eter rent ▁to ▁gr inding . ▁Gr inding ▁in ▁public ▁places ▁may ▁be ▁seen ▁as ▁a ▁form ▁of ▁v andal ism ▁and ▁may ▁cause ▁sk ate board ing ▁to ▁be ▁b anned ▁by ▁business ▁own ers ▁and ▁city ▁ordin ances . ▁ ▁Back - side ▁or ▁front - side ▁Whether ▁a ▁gr ind ▁is ▁back - side ▁( BS ) ▁or ▁front - side ▁( FS ) ▁depends ▁on ▁how ▁r ider ▁approaches ▁the ▁rail ▁or ▁edge . ▁If ▁the ▁sk ater ▁approaches ▁the ▁rail ▁with ▁his ▁back ▁to ▁it , ▁the ▁gr ind ▁is ▁a ▁back - side ▁gr ind . ▁If ▁the ▁sk ater ▁approaches ▁the ▁rail ▁with ▁the ▁front ▁of ▁his ▁body ▁to ▁the ▁rail , ▁the ▁gr