Recommended Disc Brakes for a Boat Trailer

Updated 10/23/2025 | Published 09/22/2025

Products Featured in This Question

Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 7,000 lbs

(131)

$213.36

4" Carbon Fiber Digital Caliper

(26)

$11.93

Question:

What information do you need to put together a disc brake package for a boat trailer? The trailer doesnt currently have any brakes.

asked by: Wendell H

Expert Reply:

Hey Wendell. I am going to need to know your bearing numbers or spindle size, axle capacity, how many axles you have, length of the trailer, and your lug nut pattern.

I have linked an FAQ below that'll show you how to measure your lug nut pattern.

To find the bearing numbers or spindle size, you'll want to pull one of the hubs and look at the two bearings. They should have numbers stamped into the sides of them. I'll need those part numbers to identify your spindle size which will tell me what hub you need.

If they do not have numbers stamped into the side you'll need to measure your spindles using a digital caliper like item # PTW80157. I'll need the C and D dimensions shown in the diagram below.

What is the width of your trailer's tongue?

You can add this information and any other questions you have where it says Reply to Jerred H and I'll be happy to answer them.

expert reply by: Jerred H

Bearing Diagram
(click to enlarge)

Jerred H.

10/22/2025

Hey Wendell, were you able to get the bearing numbers or spindle measurements for your boat trailer? Once you have those details, I can help you match the right disc brake package. Let me know what you find so we can get it sorted out.

Wendell H.

10/22/2025

Not yet. It will probably be awhile. I usually service my hubs after the weather get too bad to fish.

Jerred H.

10/23/2025

@WendellH Sounds like a man who knows his priorities! Let me know when you get those measurements and I'll find you the right parts. Enjoy the rest of the season.