3.5k Bearing kit (MAT)

What “3.5K bearing kit” means

• Refers to a set of components used to service or replace the wheel bearings on a 3,500 lb-rated trailer axle .

• Common on utility trailers, small campers, and boat trailers.

What’s included in the kit

A standard 3.5K bearing kit usually contains:

Inner and outer bearings – allow the wheel to spin smoothly on the spindle

Bearing races (cups) – surfaces the bearings roll against

Grease seal – keeps grease in and dirt/water out

Cotter pin or tang washer – secures the spindle nut

Dust cap – protects the hub from contamination

• Sometimes includes grease or a grease fitting

Function (MAT context)

“MAT function” isn’t a universal industry term, but in maintenance/technical contexts it usually refers to the maintenance and assembly task/function of the kit. In that sense, the function is:

M (Maintenance): Replacing worn bearings to prevent overheating, wheel failure, or axle damage

A (Assembly): Providing all necessary parts to properly reassemble the hub after inspection or repair

T (Traction/Turn): Ensuring smooth wheel rotation with minimal friction, which supports safe towing and load handling

Why it matters

• Prevents bearing failure , which can cause wheel lockup or detachment

• Reduces friction and heat buildup

• Extends the life of the axle and hub

• Improves safety and reliability during towing