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30www.directmetals.com800.711.4939BAR GRATINGStair TreadsSTANDARD TREAD WIDTHS AND END PLATE DIMENSIONS*Table of widths based on 3/16" thick bearing bars and standard bar spacing 1-3/16" cc (1-1/8" face-to-face for riveted grating.)SUGGESTED BEARING BAR SIZES**Maximum tread length based on 400-lb. concentrated load on nosing and 4 bearing bars at center of tread length. NOTE: Since a serrated connecting bar does not reduce the strength of the grating, R and AR series treads may always be selected from the “Plain” column.NOTE: DIM, B = 2-1/4"for ALL aluminum treads.NOTE: Refer to drawings above for A and B dimensions 5 6-3/16 6-1/4 6-11/16 6-3/8 2-1/2 1-3/4 2-1/4 6 7-3/8 7-7/16 8 7-1/4 4-1/2 1-3/4 2-1/4 7 8-9/16 8-5/8 9-5/16 8-3/4 4-1/2 1-3/4 2-1/4 8 9-3/4 9-13/16 10-5/8 9-15/16 7 1-3/4 2-1/4 9 10-15/16 11 11-15/16 11-1/8 7 1-3/4 2-1/4 10 12-1/8 12-3/16 13-1/4 12-3/8 7 1-3/4 2-1/4 W, SG, SGF SGI R, AR Plank Dimension 1 1-1/2 Series Series Series Series A 1-1/4 1-3/4Dimension BEnd Plate DimensionsAluminum TreadsWidth (includes nosing*) Number of Bearing Bars 1" x 3/16" 2'-4" 2'-2" 1" I-Bar / Plank 2'-6" 3/4" x 3/16" 2'-4" 1'-11" 1-1/4" x 3/16" 2'-10" 2'-7" 1-1/4" I-Bar / Plank 3'-0" 1" x 3/16" 3'-5" 2'-10" 1-1/2" x 3/16" 3'-6" 3'-2" 1-1/2" I-Bar / Plank 3'-6" 1-1/4" x 3/16" 4'-8" 4'-2" 1-3/4" x 3/16" 4'-3" 3'-10" 1-3/4" I-Bar / Plank 4'-5" 1-1/2" x 3/16" 5'-6" 5'-3"Steel TreadsMax. Tread Length*PlainW, RSeriesSGI SeriesPlank SeriesMaximum TreadLength*SGF, SG, ARSeriesSerratedMax. Tread Length*Plain SerratedSTAIR TREAD DETAILS