jedens -
No problem! /w3tcompact/icons/smile.gif
The traditional "low boy" trailers most folks think of are those that use a gooseneck type attachment and have the axles at the rearmost part of the trailer. The "low boy" I was referring to probably, to be more accurate, should be called a "drop axle" trailer.
As far as the actual height difference between the two types, (e.g. Drop axle vs. straight) it will vary based on trailer design. I would guess it it should typically range anywhere from 4"-6" difference in ground clearance.
For example, a "spring under" on a drop axle trailer will get that sucker LOOOOOW to the ground. /w3tcompact/icons/hmm.gif Kindof nice if your towing a corvette around (and don't have a tilt-bed trailer) as it reduces the breakover angle between the ramps and the bed. /w3tcompact/icons/smile.gif Bad if you have to go over anything poking up (some speedbumps) or thru dips (taildragger). /w3tcompact/icons/sad.gif
With a tractor, for the most part you don't have to worry about the breakover between the tractor & trailer (plenty of clearance) but some cars, well there could be an issue. If you are towing your trailer around on the stereotypical "ranch", well ground clearance is a necessity. If you ever go to a "true" lowboy trailer, although you won't have to worry about the "taildragger" scenario, you'll introduce issues with breakover angle and potentially "high centering" it. Just something else to think about I suppose. /w3tcompact/icons/hmm.gif
I've pasted a couple of links on trailers & axles for you to check out if you're curious, along with attaching a picture of my trailer with my tractor on it to this message. The extra height is great for towing things around on rough/uneven roads, but raises the CG and helps the mileage go down due to wind resistance. Overall, I'm very happy with my trailer - a "low boy" / drop axle simply wouldn't have worked for me.
Hope this helps! /w3tcompact/icons/smile.gif
<A target="_blank" HREF=http://www.standens.com/MeasureAxle.htm>Axle Info</A>
<A target="_blank" HREF=http://www.bnmtrailersalesinc.com/utility-trailers/drop_axle_gate_removesides.html>Drop Axle utility trailer</A>
<A target="_blank" HREF=http://www.toysandjoys.com/products/64.html>Typical Low-Boy trailer</A>
<A target="_blank" HREF=http://www.goldenwesttrailers.com/open.asp>Bunch of different trailer pics</A>