Choosing the best trailer jack for your application.

If you're looking to upgrade the trailer jack, or Jockey Wheel as the Aussies call it, on your off road or overland trailer, it can sometimes be a bit confusing as to which model is the best to suit your application. Well, worry no more, here is a basic overview of the different XO Trailer Jack models offered by Ark, and which applications they suit best.

The best model for you will be based on a number of questions about the technical specs of your trailer, and the type of terrain you plan to tackle. Here are some key things to consider:

(A) What is the height of your trailer frame from the ground?

Each trailer jack is designed for a specific mounting height range on the trailer. The tire size and suspension height are the first thing to consider when choosing a jack. The measurements (A) in the table below relate the maximum and minimum distance required from the centre of your mounting point on the trailer (typically the horizontal centre line of your drawbar frame) to the ground level. You'll want to choose a jack with plenty of allowance for raising and lowering the jack to stabilize your trailer when deployed, but also when raising the jack on to your tow vehicle. This includes on uneven ground when off road. Note also that the maximum height rating on a jack relates to static load only. If you're moving the trailer about your camp site, then the maximum height recommended when moving is also noted in the table below. This is because when moving the trailer additional lateral stress is placed on the shaft of the jack, so a minimum amount of overlap between the outer and inner shafts of the jack is required to maintain lateral integrity of the jack. Each XO jockey wheel includes a marking on the inner shaft that shows you've reached the maximum extension point recommended for moving the trailer on the jack.

(B) What is the tongue weight of your trailer?

The tongue weight of your trailer, including any cargo loaded on the tongue or forward of the axle, should be factored in to what jack you choose. Currently Ark offers jacks ranging from 350kg to 750kg static load ratings. Note that this only relates to the tongue weight of your trailer, not the overall gross weight and is typically set at between 10-15% of the GVWR of the trailer, but check with your manufacturer for the stated tongue weight. Just be sure to factor in any options or cargo that you are carrying to the tongue weight calculation as things like fridges, spare tires, propane tanks etc. can all have a significant impact on tongue weight.

It's also a good idea to build in a nice buffer between your tongue weight and the capacity of the jack. The higher the rating on the jack, the beefier the materials with which it is built, and the more wiggle room for abuse you have. For example, the weight ratings are base on a normally extended jack on level ground. If you're extending the jack out to the maximum recommended extension for moving, and then moving the trailer around in soft ground out of a deep rut, the lateral forces on the jack are greatly increased, so the more headroom you have before you reach the jack's maximum load rating, the better.

(C) What is the size of your drawbar/tongue tube?

The Ark jockey wheels come with a universal mounting bracket that is designed to fit drawbars of between 50-150mm (2-6") in the case of the XO350 and XO500 models, and 75-150mm (3-6") for the XO750 series. The mounting plate and u-channel kit supplied with each jack have pre-cut holes designed to suit this range. When choosing a mounting location, you will need to have a spot that will allow access to the inside of the tube for locating the u-channel bars, or if there is a deck or tongue box in the way, you may need to weld a mounting plate to the drawbar frame and mount the swivel plate of the jack directly to the welded plate. The kit comes with mounting bolts designed to work with drawbars of a max 50mm or 2" depth, so if your tongue is made from say 3"x3" material, you will need to source suitable longer bolts to fit your application. Tube mount models are designed to fit a standard tube mount collar found on many cargo trailers, or you can use the bolt-on tube collar that comes with the kit.

(D) Remember to check the room required for the trailer jack to swing up when in transit?

It's also important to check how much room you have between the coupler/vehicle end of your trailer, and the cargo box, tongue box, or any other items mounted to your drawbar. This will ensure that you can safely swing the jockey wheel up and out of the way for maximum ground clearance off road. 

You just want to be sure that the coupler is far enough back from the vehicle such that it won't get snagged when turning sharp corners, and is free of any obstacles that may prevent it from stowing in the horizontal position.

Note that the trailing yoke can be locked in several positions which can be very handy if you have say a spare tire sitting on the drawbar that might prevent the wheels from stowing vertically, but stowing them in the 45 or 90 degree positions leaves them clear of the obstacle. Also note that the handles on all XO series trailer jacks are attached magnetically and removable, so nothing needs to be hanging down below the trailer frame to get snagged up on obstacles off road.