There are two items of maintenance associated with the bow roller.  First however, its important to note that I don't think this roller was incorporated onto later model trailers.  R&R is hull #224 and the roller will likely be a part of trailers shipped with boats up to and perhaps some beyond that.  It would be interesting to know why the roller no longer is used.  Trailers without the roller offer two possible problems.  First, if the ramp is steep, the deck lip might catch the bow roller when launching.  Second, and again associated with steep ramps is that the boat doesn't pull forward adequately when hauling out leaving the bow not into the bow chock and a little too far aft messing up the trailer balance.  There are also some negatives to the bow roller.

• As shipped, the frame is exposed and if the hull gets outside of the frame during loading... the corners of the frame or the axle can inflict a bow wound.  Here... the frames are shielded with a piece of wolmanized 2x4 which is covered with carpet.   Construction is straight forward.

•  Drill two holes in each block for carriage bolts.  I used 1/4 x 3" galv
  
•  Locate and drill counter bores for the axle protrusions, boring only slightly deeper than the axle as this will hold the axle in place.
• Clamp 2x4s to frames and drill holes thru frames.
• Insert Carriage bolts
• Cover with carpet stapling on the side with the carriage bolts.
• Mount

The roller contains plastic inserts bearings both ends which transition the axle to the roller body.  These are subject to failure.  The fix was to turn new inserts from a solid stronger piece of plastic (hardwood would work fine).