We're changing the way we make fifth wheels. The wheel itself, (the plate) is the same cast metal one we've been using for years. The mounting plate we were using is OK but it is tricky to get the fifth wheel so it pivots easily and allows the fifth wheel to tilt back when the truck is displayed without a trailer and to fit flat against the under side of the trailer when necessary.

A better model will be created if the mounting bracket is fabricated from styrene than if one is produced from a casting machine. On the real trucks there are many ways a fifth wheel is mounted so many modelers will want to look closely at a particular truck they're modeling. Highway trucks are different than a heavy contractor's truck pulling a lowbed. Tire size and the height of the tires above the top of the frame will vary from truck to truck.

The mounting plate, the flat part that attaches to the frame of the truck is a piece of 0.015" thick styrene cut to same width as the frame, length can vary from just about the length of the fifth wheel to an inch or more.

To this add two "ears" of 0.020" x 0.100" styrene spaced so they will be just outside of the two ears of the cast metal fifth wheel. Actually this is about the same as the width of the truck frame. After the glue has cured well and hard you can drill a hole in each side and then carve them down to size and shape so they do not look bulky (make them as inconspicuous as possible) and allows the fifth wheel to pivot as necessary. You're actually making the mounting ears for the fifth wheel after they have been glued onto the mounting plate

It will also help to file down the ears (lugs) on the fifth wheel itself to allow it to sit a little lower on the frame. Make sure the holes are plenty big, they won't be seen because they're inside the ears. Pin the metal fifth wheel onto the styrene mounting with a piece of 0.020" brass rod. Bend one end of the rod at a sharp right angle for two reasons: first so it won't slide all the way through and second so it will give you something to glue to so the rod will stay in place.

This may take a little more time, not that much, but the results will be well worth the time spent. For normal highway operation the top of the fifth wheel should be 51.5" (0.591") above the ground. Truck frames are typically 40" high when 20" rubber is used, 44" with 24" tires. The 40" dimension can be a little lower with lighter duty trucks but the fifth wheel should be shimmed under the mounting plate to bring it up to standard.