LiftMaster K15-40B19LGH Sprocket, 40B19T, 1 Inch Bore
The LiftMaster K15-40B19LGH is a replacement drive sprocket identified as 40B19T with a 1 inch bore. On commercial operators, the sprocket transfers power through the roller chain to move the door or drive assembly. Worn or hooked sprocket teeth can cause chain noise, jumping, poor travel, and accelerated chain wear. This sprocket is commonly associated with LiftMaster GT and GSD commercial door operator applications, but the correct part must still be confirmed by shaft size, chain type, tooth count, and parts diagram location.
What This Part Does
The sprocket engages the drive chain and transfers rotational motion from one shaft or drive component to another. Correct tooth count and bore size keep the chain aligned and help prevent premature chain and bearing wear.
Compatible With
Use this sprocket on select LiftMaster commercial door operators that specify K15-40B19LGH or a related 15-40B19LGH sprocket reference.
- Select LiftMaster GT commercial trolley operator drive assemblies
- Select LiftMaster GSD commercial door operator drive assemblies
- Commercial operator sprocket positions requiring 40B19T tooth profile and 1 inch bore
- Applications that reference K15-40B19LGH, 15-40B19LGH, or related 40B19T 1 inch bore sprocket numbers
Compatibility and Application Notes
- This is a 40B19T sprocket with 1 inch bore.
- Do not confuse it with 41B sprockets, 48B sprockets, 3/4 inch bore sprockets, or 1-3/16 inch bore sprockets.
- If replacing a worn sprocket, inspect the chain and mating sprockets at the same time.
Features and Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Drive sprocket |
| Part Number | K15-40B19LGH |
| Sprocket Size | 40B19T |
| Bore | 1 inch |
| Application | Commercial operator chain drive assembly |
| Compatible Operator Type | Select GT and GSD commercial door operators |
| Notes | Match chain series, tooth count, bore, and diagram location |
Also Known As / Related Part Numbers
- K15-40B19LGH
- 15-40B19LGH
- 15-40B19LGF
- G155501
- 40B19T 1 inch bore sprocket
Technician Note
A new sprocket installed on a stretched or damaged chain may wear out quickly. Check chain stretch, alignment, lubrication, and bearing condition before finishing the repair.
Before Ordering
- Confirm the existing sprocket is 40B19T.
- Confirm the bore is 1 inch.
- Confirm the operator parts diagram calls for K15-40B19LGH or a related number.
- Inspect the chain and other sprockets for matching wear.
- Check chain alignment after installation.
Professional Advisory
Commercial operator chains and sprockets are pinch-point components. Disconnect power and secure the door before service.
Product Questions and Answers
What does 40B19T mean?
It identifies the sprocket series and tooth count. In this case, it is a 40B series sprocket with 19 teeth.
What operators is this sprocket commonly used with?
It is commonly listed for select LiftMaster GT and GSD commercial door operator applications.
Can I use a 3/4 inch bore sprocket instead?
No. The bore must match the shaft. This listing is for a 1 inch bore sprocket.
Should the chain be replaced with the sprocket?
If the chain is stretched, rusted, tight in spots, or has damaged links, it should be replaced or serviced along with the sprocket.
No. K15-41B32GXX is a different 41B32T sprocket with a 3/4 inch bore.
