Product updated on 2019-10-02, BellTech - BEL:2400, 1988-91 Silverado/Sierra (1/2 Ton, Std Cab) 2 inch Drop Spindle , 88-91 Chevrolet Silverado/Sierra (1/2 Ton, Std Cab) 2 inch Drop Spindle, except 454 SS, Belltech 2400, Rotor thickness is 1 inch, if 1.25 use part number 2500 CAUTION: Wheels with more than 3 1/2 inches of backspacing, (including the factory 7 inch wheels) will interfere with the lower control arm which impairs the vehicle’s steering and are cautioned against. This rim contact with the lower control arm is indicated in Photos 8 and 9 of the instructions. We recognize that it is a common practice to trim the lower arm to eliminate the rim contact areas to provide clearance for wheels with more than 3 1/2 inches of backspacing. We have not determined the affect of such modifications on the structural strength of the lower control arm nor what other risks attend such modifications. IMPORTANT NOTE: Any person modifying stock components does so at their own risk.