Where to mount d-rings in trailer?

This is really a few questions in one. This is a 26' enclosed trailer.

1) Where should the car be positioned in the trailer? Should it be centered over the trailer wheels or further forward/back? I know this depends on how you want the weight in the trailer distributed, but, in general, what's the best position?

2) Now that I have the car position, where do I put the d-rings? This probably depends on what I use on the car as an attachment point, so what should I use for that?

3) How do I mount the d-ring? I've been looking at the recessed ones and they require a hole be cut in the floor. Is it easiest to do this with a reciprocating saw or something else?

Thanks for any info. I'd like to get this right the first time.

David

For a VERY general answer, to a very general question; I'd say the car should be placed so that it's CG was slightly in front of the center of the axle(s). Most trailers are designed so that >15% of the empty mass is forward of the axle center, for empty towing stability, so as a rule of thumb that should do just fine.

If you really want to get carried away with it, do the geometry and figure out where the car needs to be (taking into account all the other stuff you'll have aboard) to place 20% of the total loaded trailer weight on the ball. (And then get an equalizing hitch, because with a 26' trailer and car and hardware, you'll be at >1400# on the hitch.)

What ever you do, make sure you use some type of steel back-up plate for the D-rings.

At the 2004 Runoffs, John Salisbury had his H-Prod (a very light car) pull the rings right out of the floor on the tow from Illinois to Ohio. Smashed up the radiator pretty good when the car rolled back and forth inside. Fortunately the door was strong enough to keep from breaking out.

I'd suggest you put E-track in the floor so that you can experiment with tie down points to get the optimum tongue/gross ratio. This also allows you much more flexibility when towing different vehicles. Through bolting the e-track also spreads the load of the anchor points over a much larger area.

Having just installed rings in my trailer let me say this...plan very carefully before you cut the floor. I tied the two in the rear into the main frame rails and the front two to a crossmember. It turned out good but I had to fudge things around a bit because I didn't plan it out as well as I should have.

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Chris Ludwig
08 ITS RX7 CenDiv

Also, watch out for the brake lines as well as the electrical stuff, before you start cutting and/or drilling on the floor of the trailer.

E-Track will give you more flexibility to carry different vehicles, and/or of your just moving the car from place to place, without the tools, spares, tires, fuel jugs, etc.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html

Thanks for the replies so far.

I have a weight distributing hitch along with a cam style sway control so I should be ok in that department.

I like the idea of using e-track, but I didn't think it would be strong enough to hold a car. Do you just run a bolt through the floor (using a backing plate) every so many inches to get the needed strength? What about the strap attachment to the e-track. Is there some sort of special attachment you should use? Most of the ones I saw didn't look like they could hold a car.

Thanks.

David

A friend had is rig rolled, and his car hung suspended while the rig slid down the embankment.

Damage to car? none.

Think about what happens in incidents like that. I put mine into the frame rails.

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

I've been using e-track for years. It wasn't in the original question, so I didn't say anything.

Will it hold the car? Properly attached, yes. It has holes about every 4" along both sides. Put a bolt and large fender washer on every hole, and through bolt the ones that hit a frame rail. For holding down a car, I'd recommend pieces a minimum of 2' long. It comes in 10' sections.

You can also get it with vertical slots instead of horizontal. I use that on the walls for all sorts of things. You can get a pair of aluminum "shoring bars" from either a semi-trailer supply place or Racer Wholesale and use them with the vertical e-track (also called a-track) for a tire rack.

For the attachment hardware, go to a semi-trailer sales or repair facility. They have latch links for e-track rated at 5,000# each.

http://home.alltel.net/jberry/img31.jpg

I bought my E-track from McMaster-Carr (it is Kinedyne brand) and McMaster-Carr is about 30 minutes from my house so shipping it wasn't a concern.

I bought the D-rings elsewhere so that I could find them with higher weight ratings without having to go with commercial trailer rated stuff.

Here is in example of what is available:

http://www.etrailer.com/y-143.aspx

Thanks for the picture. That helps alot. I'm still a little confused about how you mounted the e-track to the floor. Did you just screw the bolts into the floor (except for the ones that hit a frame rail)? Do your bolts poke through underneath? Did you put some silicone or other stuff around each bolt to keep water from seeping through if you're driving in the rain?

Looks like the e-track on the floor is about 1 1/2 to 2 ft from each side and maybe 4 ft between the tracks in the middle? So the e-track would sit inside the car's wheels and extend out from under the car in the front and back?

I was looking at using vertical e-track no matter what I did on the floor. I like the idea of using shoring bars to build a tire rack. Did you use the same method to put up the vertical e-track as you did for the floor?

Sorry for so many questions, but I'd rather not figure out things by trial and error if somebody already has a way that works.

www.trailer-parts-forless.com seems to have a good selection of e-track fittings, but their track price is a little higher than other sites.

Thanks again.

David

Yes, the bolts poke through. I don't trust just screwing the bolts into the flooring. No, I didn't seal them (although it's probably not a bad idea). Water migration has never been a problem.

The e-track is positioned, essentially, as you describe - it's between the wheels of the car. Now - also take into consideration that you will probably not position the car directly in the center of the trailer, for doo opening clearance and additional storage reasons. I screwed up on that part, so the car actually isn't centered on the e-track. My recommendation: test fit the car on the trailer, and position the e-track after you determine where you will put the car.

The vertical e-track is on 16" centers, and is bolted into the wall trusses with self-tapping bolts (also obtained from the trailer repair company - in my case, Liberty Trailer, in North Little Rock, AR.).

If you wann'a get really keyed up - that trailer (a 2001 39' U.S. Cargo with living quarters) and its tow vehicle (2002 Ford F-550 Super Crew) are for sale for about half the new prices. http://Forum.ImprovedTouring.com/it/wink.gif

So you used a nut and washer on the underneath side for each bolt? I was thinking of running a pair of e-track down the entire length of the trailer on the floor so that I could strap other things to the floor as well. That'd be a lot of drilling and "nutting", though, if I put a nut and washer on the underneath side for each bolt.

I'm using the trailer to go pick-up the car (along with all the spare parts, wheels, etc. that go along with it). So I won't have the car when I mount the e-track to the floor. I'll have to make my best guess as to where I want the car positioned. Does having the car off center affect how the trailer pulls at all?

Thanks for all the info.

David

I won't say that ALL the fasteners are bolt-washer-nut, but that's what I asked them to do. I do know that a goodly portion of them are.

Just keep in mind that when you position the car for optimum load balance, the doors will most likely hit the trailer's inside wheel arches when you open them. If the car is an open car, it's no problem - but in a sedan, it can be a PITA to get in if the door will only open a few inches. You've got (at most) about of 96" inside width. The wheel arches probably are 6" - 8" wide, bringing your clearance down to as little as 80" (or 40" center-to-edge). Assuming the car is 66" wide (fairly average for IT cars), that leaves you only 7" to open the door.

I've never noticed a relevant difference with the car offset side-to-side, even on a light open trailer.

<edit> In this particular trailer, which weighs 16K loaded, the offset of the car (to the right) is moderated by 1300# of generator, fuel, and water tanks - all of which are mounted to the left of centerline. </edit>

[This message has been edited by ITANorm (edited January 06, 2005).]