Parts Needed to Add Brakes to Single Axle Boat Trailer


Purchased a boat trailer thats needs some help. Boat is a 22foot I/O walk around Galaxy, weighs 2,850 lbs on a single axel Loadmaster Trailer. Previous owner drove the trailer about 300 yards at a time to put in and take out the boat. He had 14inch rims with 205/75R14 95S tires. My perspective accident waiting to happen. Per Title, Aluminum Trailer is 1998, 480 empty weight, 3,500 gross weight. Need advice on upgrading to at least 15inch rim. Trailer Manufacture current standard on this range trailer is a 15”C 5 lug. Outboard looks close to close to the ground on the 14inch tires. Looking for 5 bolt and Dinch rated trailer rims/tires rather have a rating a little over than a little under as well as, adding trailer brakes. Salt water use but mostly need to drive 2 hrs by road 55 MPH max, to launch boat into a seasonal slip and pick it up end of season. It has rusted square plate with four holes at the spindle. Most inexpensive options that meet my safety needs. Thanks!


Expert Reply:

You can increase the size of the wheels and tires on your boat trailer so long as you have enough room in the wheel/fender wells. Normal suspension travel usually dictates no less than 4-inches of clearance at the top of the tire. Provided you have enough room to prevent the larger tire from contacting any trailer surface you can go with ST205/75-15 rims/tires; the linked page displays all products that combine a 5-on-4-1/2 rim with a 205/75-15 trailer tire.

For instance, part # A15R645SMD is a radial type Load Range D tire/silver rim rated for 2150-lbs at 65-psi. This tire carries a speed rating M, meaning up to 81-mph. This tire is ideal for highway use.

You can add brakes to your trailer since it sounds like you have 4-bolt brake flanges in place. The least-costly option for adding brakes is to go with electric drums. Boat trailers more and more these days are being fitted with OEM electric drum brakes since they cost so much less and are easier to install and maintain than hydraulic drums or discs. You can refer to the linked article for details on the process of adding electric drums brakes to a trailer.

You will need to determine your axle rating to find the correct brake capacity. For a 3500-lb axle the 10 x 2-1/4-inch brake size is typical. Brakes # AKEBRK-35R-SA (right) and # AKEBRK-35L-SA (left) have a 4-bolt mounting pattern to match your flanges. Your new hub/drums must use the same bearings as your current idler hubs in order for them to fit on your spindles. If you have the common 68149/44649 bearings you can use hub/drum # 84546UC3.

Electric brakes require the vehicle have a 7-way trailer socket and brake controller. If you have a factory 7-way all you need is the controller, such as the Primus IQ # TK90160, but if you do not have a factory 7-way you will also need our installation kit # ETBC7 which includes a 7-way and all the items needed to install the Primus. You'll also need a junction box/7-way plug like # 277-000141 on the trailer to connect the trailer brake and light wiring.

expert reply by:
Adam R

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