What are Forklift Mast Bearings? A Complete Guide to Mast Rollers & Guides

Forklift Mast bearings, also known as forklift mast guide rollers, carriage bearings, or simply mast rollers, are engineered to withstand high intermittent shock loads and heavy radial forces typical in forklift operations.

Understanding Forklift Mast Bearings

Forklift bearings are vital hardware components that ensure the smooth operation of the lifting mechanism.

At TFL Bearing, we utilize advanced high-speed forging technology and premium bearing steel (such as GCr15) to produce mast rollers. Our designs feature a rated load capacity 5% higher than standard bearings, ensuring durability under extreme conditions. With an actual lifespan extending 5 to 8 times beyond standard ratings, our bearings are the preferred choice for aftermarket replacement.

Available Load Capacities: Our forklift mast bearings range from 0.5 tons (1100 lb) for light-duty trucks to over 25 tons (55,110 lb) for heavy-duty industrial forklift masts.

What Are The Types of Forklift Mast Bearings?

There are four main types of Forklift Mast Bearing:

Mast Guide Roller Bearings (Side Rollers)

Mast guide bearings (also known as side rollers) are critical for preventing lateral movement. Unlike the main load rollers that carry the weight, these bearings guide the mast stages and the carriage, ensuring vertical stability. They handle the side thrust generated when the forklift turns or carries uneven loads.

• Mounting Location: Usually mounted on the side of the fork carriage.

• Key Feature: Designed to withstand high impact and side loads.

Part number	d	D	b	B	R	Cr.	Cor.	Weight
	mm	mm	mm	mm	mm	dynamic	static	lbs.
MG205-1E	12.6	57	20.5	26.95	1	16100	11000	0.75
MG205-2E	13	52	18	24	2	16100	11000	0.75
MG305-7E	17	72.8	33.6	25	3	27000	18800	1.45
MG305DDTY	25	62	19.5	18	3	43690	45620	0.75
MG205FF	25	65	15	21	6	14020	7880	0.75
MG205FFX	25	67	15	26	4.5	14020	7880	0.85
MG305DDY	25	71	17	21	2	22390	11490	0.9
MG305DDH	25	72	28	28	2	61240	65950	1.45
MG305DD	25	76.2	17	25.4	8.38	20510	11120	1.25
MG305DDB	25	76.2	17	25.4	8.38	20510	11120	1.25

Carriage Bearings (Side Thrust Rollers)

Carriage bearings, also commonly referred to as side thrust rollers, provide lateral guidance to the fork carriage as it travels up the mast. These bearings are essential for preventing the carriage from shifting side-to-side.

• Size: They are typically smaller than the main mast guide bearings.

• Function: They adjust the clearance between the carriage and the mast rail.

Side Thrust Roller Bearings (Lateral Guides)

Side thrust roller bearings play a crucial role in transferring lateral (sideways) loads to the forklift mast, helping to prevent twisting and ensuring smooth vertical movement. Typically mounted on a shaft or pin, these rollers are subject to high friction and often require replacement to maintain mast alignment.

• Function: Prevent metal-on-metal contact between the carriage and mast rails.

• Installation: Usually adjusted with shims to ensure the correct clearance.

Side Thrust Bearing Size Chart
The table below lists the specifications for common side thrust rollers. Check the Shaft Diameter and Roller Width to match your forklift model.

Side roller bearing
Bearing	size			Bearing Model	size
	internal diameter	external diameter	High		internal diameter	external diameter	High
84904	20	42	80	CN-9	24.4	47	80
84905	26	52	84	CN-10	31	58	62
L4902	15	33	58	CN-12	19	34	80
C2-3	20	58	80	CN-13	24.8	54	62
C4-5	25	67	85	CN-14	21.4	40	80
C6-10	30	82	90	CN-15	20	41	75
CN-2	21.4	40	80	CN-16	30	87	90
CN-3	21.4	40	62	CN-17	25	42	201
CN-4	21.4	58	65	CN-18	45	90	62
CN-8	21.4	47	6580	CN-19	20	34

Chain Roller Bearings (Chain Sheaves)

Chain roller bearings, technically known as chain sheaves or pulleys, are responsible for guiding the leaf chain that raises and lowers the mast. These bearings feature a flanged design to keep the chain aligned and captive during operation.

• Function: They bear the massive tension of the lift chain.

• Maintenance: Worn sheaves can damage the chain, so they should be checked regularly for wobble or flange wear.

Chain Sheave Size Chart
Find the correct chain roller for your forklift mast using the dimension table below.

Bearing NO.	Dimensions（mm)						Bearing NO.
I	d	D	D1	C	C1	B	II
7830306	30	96	80	24	16	19	L60306
780606K	30	87	75	34	22	26	L60606K
780506	30	134	115	32	22	28	780506K
780308	40	120	110	40	30	23	F60308
780308K	40	140	120	34	27	23
780708	40	118	100	32	26	23
780708K	40	118	100	34	27	23
78070K1	40	113	95	32	21	23
780408	40	134	115	39	29	27	L60408
780309	45	138	125	58	34	25	S60309
780309K	45	126	110	56	25	25
780309K1	45	126	110	47	37	25
780309K2	45	126	110	30	25	25
780309K3	45	126	110	44	34	25	A60309
780709	45	126	110	38	28	25
780709K	45	125	110	35	25	25
780310H	50	148	134	41	25	27
780310K	50	141	122	46	27	27
780711	55	122	110.5	40	28	21	780711K
780411	55	160	145	52	36	44.5
722711	55	144	122	56	43	40
780415	75	218	200	65	49	53

 Checklist: Identifying Your Forklift Mast Bearings

Signs Your Forklift Mast Bearings Need Replacement

Regular inspection is key to safety. If you notice any of the following, it’s time to replace your mast rollers:

1. Excessive Play (Wobbling): If the mast stages move side-to-side too much when extended, the side thrust rollers or mast guides are worn.

2. Metal-on-Metal Noise: Grinding or screeching sounds during lifting indicate the bearing coating or outer ring has failed, causing friction against the rail.

3. Uneven Lifting: If the carriage gets stuck or doesn’t lift smoothly (jerky movement), the chain sheaves or main rollers may be seized.

Need a replacement but not sure about the part number?

Our technical team are experts in forklift mast identification. To get a quote quickly and accurately, please provide as much of the following information as possible:

1. Forklift Brand & Model: (e.g., Toyota 8-Series, Linde H30).

2. Part Number: Check for any numbers stamped on the bearing race or look it up in your parts manual.

3. Dimensions (Critical): Measure the Inner Diameter (ID) x Outer Diameter (OD) x Width (B). Precision is key.

Compatible Brands for Aftermarket Replacement

TFL Bearing manufactures high-quality aftermarket mast bearings suitable for most major forklift brands, including but not limited to:

• Toyota (e.g., 7-Series, 8-Series)

• Linde

• Hyster / Yale

• Komatsu

• Nissan / TCM

• Mitsubishi

• Caterpillar (CAT)

Note: We provide cross-reference part numbers to help you find the exact match for your OEM parts.

Custom Manufacturing & OEM Services

If your bearing is obsolete or you have specific OEM requirements, Shandong Tefule Bearing can manufacture mast bearings to your exact specifications.

• Fast Turnaround: We can produce custom bearings based on your sample or drawing with lead times as short as 24 hours.

• No Minimum: We support both small replacements and bulk orders.

Explore Our Full Inventory:
Click here to view our latest Forklift Bearing Catalog covering all sizes and types.

Frequently Asked Questions about Mast Bearings

Q: How often should I grease forklift mast bearings?
A: Most modern mast rollers are sealed for life and do not require external greasing. However, the mast rails (channels) should be lubricated regularly with appropriate chain and cable lube or molybdenum disulfide grease.

Q: Can I replace just one bearing?
A: It is highly recommended to replace mast bearings in pairs (or complete sets). Replacing only one can cause uneven load distribution, leading to faster wear on the new bearing and potential mast damage.

Q: What is the difference between a mast roller and a chain sheave?
A: A mast roller runs in the mast channel to guide movement, while a chain sheave is a pulley that holds the lift chain.