How do you determine depth of dropped floor on canned ham?

[lstyles]

I've made some progress on my trailer frame design but I am to the part where I need to design in the drop floor. I prefer the drop floors that come out all the way to the side of the trailer (like Doug's trailer) so you don't have to step down into them. My question is how do you determine how much you can safely drop the floor? I am guessing that wheel size and axle probably play a role in determining this but what is the minimum clearance etc that I should have?
thanks,
Lori

[doug hodder]

Lori...I asked an open question for just how low people had their dropped floors on either a canned ham or a tear. From the ground to the bottom of the 2x longsill (doorside) on the frame I'm at 6 5/8" when level. This is the lowest point on mine. A flexiride axle is a real + as it's very difficult to determine the exact height if you don't have a fixed weight in mind. You can adjust the axle to bring it up a bit as well as make the dropped floor extend further back and wider since you don't have to deal with spring hangers and their bolts.

Other variables...wheel diameter and in my case, garage interior and garage door height. I've only got a 5" drop on the floor in mine, others are deeper, but I didn't want a really tall trailer. If you go with a short design, you will also need to get the correct tongue jack. Too tall on the mount and you won't be able to get it level, or pull the dolly wheel when it's on the hitch ball and run the risk of dragging it, if the frame sits low. I got one that is a jack only, no mounting system and created my own to customize the jack height.

I worried about dragging something, but so far, haven't had any issues with it being too low and the trip into DMV parking lot was risky, but no drag.

On a side note....it would be to your advantage to install some skid type plates on some of the portions that could drag as insurance. Scotties had them. Doug

[lstyles]

Thanks for the response Doug! So then it would seem I should build the trailer and mount the axle and wheels and see how it sits before deciding on how low I can go? That makes sense and I think that is doable. I am thinking that 14" wheels will be best does that sound right (not to small not too big) for a 16ft canned ham (13ft body, 3 ft tongue).
Lori

[doug hodder]

I've got 14's on mine, but the deal for me was that I wanted a 14 with as wide of a whitewall as I could get so that's what drove my tire size. That may not be important to you. I had no idea of exactly how much the whole thing would drop once all the weight was on the flexiride. As it ends up 2500#..set at 0 worked for me. I think I'd get one de-rated a bit if I were to do another, but this seems to ride fine and doesn't shake it to pieces. I don't do a lot of either "off road" or gravel unpaved road travel however.

PS...I am also using automotive type tires, not trailer rated ones. Wide whites aren't available in the trailer ones. Others may think I'm stupid for doing this however. Make sure that your tires can handle the weights you are planning on. Mine is only like 11' long, 1400#. You might want to check what you have for a tire on your tow vehicle and if it's the same bolt pattern, go for that size so that you have a built in spare. 15's would probably be more in line on a 16'. Just my opinion, others may vary. Doug

[cuyeda]

...snip...
On a side note....it would be to your advantage to install some skid type plates on some of the portions that could drag as insurance. Scotties had them. Doug

Another side note... Skid rollers!


Check this sample link out.

http://tweetys.com/search.aspx?find=skid+rollers

[48Rob]

I've always believed that the depth of the dropped floor can be determined by setting the trailer tongue on the ground, and measuring from the ground up at the forwardmost point of the drop floor area.
Next, measure the max spring, or torsion axle travel, subtract that number from the first, then add a couple inches for safety.

As the guys pointed out, skid plates or skid rollers are a wise investment, as is a well built steel front plate or bar to prevent damage to the floor if an obstruction in the road can't be avoided.

Rob

[Mark72]

PS...I am also using automotive type tires, not trailer rated ones. Wide whites aren't available in the trailer ones. Others may think I'm stupid for doing this however. Make sure that your tires can handle the weights you are planning on. Mine is only like 11' long, 1400#. You might want to check what you have for a tire on your tow vehicle and if it's the same bolt pattern, go for that size so that you have a built in spare. 15's would probably be more in line on a 16'. Just my opinion, others may vary. Doug

Doug, Coming from my tire business experience, I think the choice to use automotive tires is a good one. The only difference I know of in a trailer rated tire is a slightly stiffer sidewall. What I have experienced is the fact that trailer rated tires seem to be very prone to tread separation resulting in serious damage to many a camper. I will never run a trailer tire on anything I own.

Mark

[Steve_Cox]

If it is of any help, traffic speed bump heights range between 3 and 4 inches with trend toward 3 - 3 ½ inches maximum. They just look and feel a lot higher. My gypsy trailer dropped floor has 7" of clearance with the trailer loaded and on the level. Never had a bottom out problem yet, the drop floor is all in front of the axle.