chain causes the rollers to climb up the coast side flank as the rollers progress around the sprocket wrap with the addition of appreciable chordal pitch reduction the extent to which the rollers climb up the coast side flank in increased it is important to note that chordal pitch reduction is required when the pressure angle u03b3 has a negative value otherwise as shown in fig1 and 17 roller 162 would interfere with the engaging flank with a maximum material sprocket and a theoretical pitch shortest chain as it exits the wrap 158 back into the span also the reduced chordal pitch assists the staged mesh as previously mentioned fig1 showing the roller contact progression in the wrap 158 serves also to show why the shallow u03b2 39 angle and tooth space clearance tsc helps maintain 34 hard 34 roller sprocket contact for the rollers in the wrap in addition the disengaging flank roller seating angle u03b2 39 fig9 may be adjusted to have a maximum value which is equal to u03b1 min 2 or even less this reduced seating angle u03b2 39 promotes faster separation when the roller leaves the sprocket and enters the span this reduced angle u03b2 39 also allows for the roller in a worn chain to ride up the coast flank surface to a less severe angle as the roller moves around the sprocket in the wrap the invention has been described with reference to the preferred embodiments obviously modifications will occur to others upon a reading and understanding of this specification and this invention is intended to include same insofar as they come within the scope of the appended claims or the.