How To Adjust Boat Rollers On Your Trailer

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How To Adjust Boat Rollers On Your Trailer

“I no longer strain my back when trying to launch my boat. It just flies off the rollers into the water”

One of the most common questions customers ask me when they call up looking to replace their boat trailer rollers on their trailer is how to actually adjust them correctly. I have created this blog article which will hopefully assist a lot of you on provide some guidance when it comes to adjusting the rollers on your trailer.

When it comes to choosing new boat trailer rollers for your trailer, there is a lot of confusion as to what the differences between the types of rollers actually are. To give a quick understanding here is the main differences.

  • Black Rubber Rollers: can be used on either aluminium hulls or fiberglass hulls. Black rubber rollers are usually of poor quality and can crack and split causing potential damage to your boat and trailer.
  • Blue HDPE Polyethylene Plastic Rollers (Blue Poly): Blue Poly Rollers are commonly used on aluminium boats and trailers. They are of higher quality plastic and are less likely to crack or split. HDPE Plastic rollers usually come standard as blue in colour in the boating industry however can be machined in any colour such as red, grey, black and so on. The colour is irrelevant to the performance of the rollers.
  • Red Polyurethane: are commonly used on fiberglass hulls only. Polyurethane rollers are red in colour however lately some manufacturers have been machining these rollers out of a yellow material. Polyurethane are tougher then rubber and an ideal replacement if you’re looking for style and performance.

In an upcoming article we will discuss the major differences, pros and cons to each different type of boat trailer part. Why you should use a specific type and why. For the purpose of the following guide we will not list any specific rollers to use but rather use a generic roller in terms of a correct setup.

First thing when looking to adjust the rollers on your trailer is to draw a ruff sketch and a plan of your boats hull. Don’t forget to include planning of the strakes and take all measurements from the hull’s center line. Make sure you take the boat off the trailer when you are ready to work on your trailer.

“A great tip is to launch your boat down at the boat ramp and simply work in the car park.”

  1. Make sure you install high quality trailer rollers. If your rollers can’t turn with a piece of fishing line wrapped around them then they will most likely need replacing or attention.
  2. set your width measurement first. Be sure to measure from center of the boat to each strake (I like to run the strake in the center of the roller arm)
  3. Next, set your keel roller height with a string line running from front to back. Angle should be approximately 5 degrees to about 8 degrees. The trick is to take the measurement from the 2nd roller at the front not the first as each hull has a different entry angle. Do the front keel roller last after the wobble rollers are finished.
  4. Back all the wobble rollers off about 10-15 mm (lower) and then pull the boat back on ensuring the boat is on the center of the keel rollers.
  5. Jack each wobble roller up (Starting from the back) until it is touching the hull of the boat but not taking the weight. Make sure you check both sides of the roller arm to ensure that both rollers are touching evenly on both sides).
  6. Back off the keel rollers approximately 1/4 to 1/2 a turn on the height bolts. Drive your trailer up the road or around the car park to settle the boat down onto the trailer.
  7. Lastly; reset the keel rollers to just take the load of the boat including the front bow roller and self centering rollers. You should now have the boat supported between the strakes and the keel evenly and still have roughly a 5 degree down slope. If you haven’t you will need to repeat from step 5.

Once completed your boat trailer should now launch much easier, the slight incline/decline will allow the boat to move without much assistance saving all your energy for your day out on your boat.


This is a basic introduction on how to adjust the rollers on your trailer. Keep in mind most peoples trailers are made by different manufacturers, are different models and contain different size rollers. Always adjust your rollers to suit your boat trailer.

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