Kind of in the market for a new flatbed. I'm used to pulling a 48 step with a 13" kingpin set way behind center of axles due to an 8' upper deck. What are the pros and cons of the various kingpin depths on a flat? I'm seeing 12,18, 24, 30 and 36" settings with 24 and 30 being the most common.
The more shallow the king pin the more you can hang off the front. The only reason I see for a deeper kingpin to the meet the KPRA laws in certain states.
Well, there is the weight issue too. With a regular depth, I get a little weight on the steer, drives, and try to keep the spread under 36,000. I don't know how much a 13" would be.
You would load a 18” kingpin trailer 1’ farther forward then a 42” kingpin trailer and end up with the exact same weights.
I had the king pin and plate replaced on my high boy flat (rusted out) Was 24” and I had them replace it to 12”. Love it. It gives a foot more front overhang and didn’t really change the center as far as I can tell. 5th wheel is right at the front of the plate now.
Bear in mind the deeper the pin setting, the closer the landing gear will be to your mudflaps. Also the further it will stretch your air lines (sometimes too far) in sharp and over 90 degree positions Con of a really short king setting is that you can occasionally drag the air lines on the 5th wheel plate in sharp turns resulting in a mess of grease all over them Both airline scenarios assume a somewhat typical airline off back of cab to front of trailer Only other thing I might consider is if you get on your step deck from your truck catwalk, the deeper pin settings are less likely to have you step in the 5th wheel grease that runs off the front edges of the fifth wheel, but a big gob of it might land on the catwalk far further forward than you're used to
Shallower kingpin and a rear set wheel will be hard to load the steer axle. Flatbeds are typically 30-36" kingpin. I person run a 30" on my stepdeck, but I have 11' top deck. If I bought another flatbed it would have a 30-36" kingpin to get the weight on the drives and off the trailer. And I'd have the fifth wheel set at center of the axles on the drives. I'm surprised you can get any weight up front with that wheel so far back.
