Overview
This Kevlar-reinforced deck drive belt is an aftermarket replacement for OEM part numbers 954-05078, 754-05078, and 490-501-C070, used on 50-inch zero-turn mowers from Troy-Bilt, Cub Cadet, Craftsman, and MTD. Kevlar cord construction resists heat and stretching better than standard rubber belts, which translates to longer service life under the high loads a 50-inch deck generates. Replace it when you see cracking, glazing, or the blades start engaging sluggishly.
Key specifications
- Belt dimensions: 5/8 in. wide x 143-1/2 in. outer circumference
- Belt type: Kevlar-reinforced deck drive belt
- Deck size: 50 in.
- Replaces OEM part numbers: 954-05078, 754-05078, 490-501-C070, CMXGZAM501083
Compatibility
Fits Troy-Bilt Mustang XP 50 (2015-2018) and Z50 zero-turn mowers; Cub Cadet RZT-L50, RZT-S50, RZT-LX 50, RZT-SX50, Ultima ZT1-50, and ZT2-50; Craftsman Z 550, Z5600, Z5650, and ZS6700 50-inch zero-turn mowers; and MTD RZT-50 and ZT-50 models. Always cross-reference your mower’s model and serial number to confirm belt length before ordering.
Installation notes
Engage the parking brake and disconnect the spark plug wire or battery. Raise the deck to the highest position, then remove the belt covers and any belt keepers around the pulleys. Release the idler spring tension and slide the old belt off. Route the new Kevlar belt following the belt routing diagram on the mower frame or in your manual, making sure it seats fully in every pulley groove. Reinstall keepers and covers, then briefly engage the blades at low throttle to confirm proper tracking.
Common questions
Q: Will this 5/8” x 143-1/2” deck belt fit my 2017 Troy-Bilt Mustang XP 50 with the 50-inch deck?
Yes, this belt is made for Troy-Bilt Mustang XP 50 models from 2015-2018 and matches the 954-05078 deck belt spec. It is designed as a deck drive belt for the 50-inch cutting deck, so it should be the correct fit as long as your mower uses that OEM belt number.
Q: I have a Cub Cadet Ultima ZT1-50. Is this the right replacement belt, or is it only for Troy-Bilt models?
This belt is also listed as a replacement for Cub Cadet Ultima ZT1-50 and ZT2-50 models that use OEM belt 954-05078. The best way to confirm is to compare your current belt number and deck size, since Cub Cadet used different belts across some 50-inch variants.
Q: Does the Kevlar construction help, and is there anything I should check when installing this belt?
Yes, Kevlar belts typically handle heat, shock load, and repeated engagement better than standard belts, which is helpful on zero-turn mower decks. During installation, inspect the idler pulleys, belt guards, and spindle pulleys for wear or buildup, because a new belt can wear quickly if a pulley is rough, bent, or out of alignment.
