The Kubota KX121-3ST runs a 350x54.5x86 track: 350 mm across the tread, 54.5 mm between links, 86 links around. Cut for digging, trenching, backfill and tight-quarters work and shipped free to the lower 48.
What the numbers mean on a Kubota KX121-3ST
- 350x54.5x86 — 350 mm tread width (about 14"), 54.5 mm pitch, 86 links
Width is the tread face, pitch is the distance between drive lugs, and links is the count around the loop. All three have to match — a track one link off will not tension correctly no matter how close the width is.
Tread choice for the Kubota KX121-3ST
Size gets the track on the machine; tread decides how it works and how long it lasts. What we stock for this one:
- Non-Directional — turf and finished surfaces. Minimal ground disturbance
Undercarriage parts for the Kubota KX121-3ST
Rollers, idlers and sprockets wear on the same clock as the track. Fitting new rubber over a hooked sprocket or a seized roller is the fastest way to lose the new track — check these while the tracks are off:
- Drive sprocket — SPRD118-14433
- Bottom roller — TRRD118-21700
How these wear
Excavator undercarriages load one side hard on slew and travel, so link cracking usually shows up before the tread wears out. Replace in pairs where you can: a new track running against a stretched one loads the drive unevenly and you will feel it in the steering.
Same track, other machines
Track size follows undercarriage geometry, not brand, so 350x54.5x86 shows up on machines from several makers. If you run any of these alongside the Kubota KX121-3ST, it is the same belt:
- Kubota KX040-4
- Kubota KX040-5
- Kubota KX040H
- Kubota KX121-2
- Kubota KX121-2S
- Kubota KX121-3
- Kubota KX121-3S
- Kubota KX121-3SS
Not sure which you are running? Read the size off the inside of the old track, or call (850) 816-7898 and we will pull it off the machine record. The Track Finder works by make and model too.
