Axle Placement for Teardrop/Cycle Hauler w/6'x12' Trailer.

[sandman]

Hey Guys,

I need some of you gurus help like badly!!! The trailer shop is ready to mount the axle on my custom built trailer and I have NO CLUE where the placement should be. I am following the specs for the Little Guy Sport Model teardrop/cycle hauler. I tried to get some info from little guy but they do not give out all their specs. Here is the actual specs I am following based on their info. Can any of you guys figure based on specs and photos as to how far from the rear of the trailer the axle should be placed. I need this info badly since the trailer shop is waiting on me to figure it out.

Ground to top of vent 68”
Outside trailer front to trailer rear 96”
Outside bumper to tongue 17’8”
Inside width 72”
Inside height 42 ¼”
Inside front to rear longest point 90”
Inside front to rear on floor 72”
Front on floor to hatch opening 98” Roof vent rough opening 14 ¼” x 14 ¼”
Payload platform 61” L x 72” W
Front overhead cabinet 16” H x 13” D x 71 ½” W
Rear counter top 14” W x 75 ½ L
Rear storage cabinet 9” D x 17” H x 71 ½” W
From hatch 66 ½” W x 20 ½” H for storage

[brian_bp]

I have read references in other topics to a calculation provided here in T&TTT, so I won't confuse the issue by suggesting my own method.

This might be Trailer Balance in the Design Library (Andrew's site). If using that guide, the tongue weight (W2) would be the motorcycle(s).

I do have a suggestion: run the calculations for two conditions - with and without the motorcycle(s) - to ensure that the axle placement produces appropriate hitch/axle load distribution in both cases.

[BrwBier]

If you are building very close to what a little guy would be (no cabinets, just a shelf) and use appropriate materials, then I would just put the picture and measurements on graph paper. I would think that would get you very close. A lot of weight distribution can be achieved with placement of gear when packing for a trip.
Brwbier

[sandman]

I wished I could review the spreadsheet on axle placement but I don't have Excel installed on my pc.

[Nitetimes]

Because you are building one like that I have to assume you have a TV that can take the tongue weight. So here's the best advice I could think of at the moment.
Figure out where your door is going to be on your cabin profile, consider what fenders you are going to use and the mounting position they will need to be in in relation to the door. Where ever that all comes out to is where you'll want to put your axle. Sorry I can't give you any real numbers but you should be able to get a location if you do as I described.
There really is no way to calculate your tongue weight and such to use as your axle placement because of the long nose and carry rack up there. Tongue weight really won't be very adjustable.

I would however try to squeeze the axle as far forward as possible even if you only have an inch or so clearance between your door and fender.
If you had a drawing of your profile and all the measurements you plan to use we could probably give you an axle center number.

[volfanatic72]

Sandman:

You can download a copy of Open Office off the web. It can do anything that Microsoft Office can do... and it's free.

[madjack]

SM, because of the radical nature of what you are building nothing we do here applies very much...the standard rule of thumb for utility trailer building is a 60/40 split front to rear...if your trailer is the same length as the LG (17'8"), that would put your axle at 81 inches...probably fine for loaded but would NEVER be acceptable when not loaded with your toys...looking at the LG pics, it appears that the axle is about in the middle of the body or somewhere around 4' from the rear...hope your tow vehicle can take several hundred pounds of tongue weight...some sort of helper springs or air ride on the rear of TV may be called for as well.......
madjack

[sandman]

My tow vehicle is a full size Toyota Tundra with a V-8 so pulling will not be an issue. The tongue weight will be 140lbs like the real Sport model. So far the welder thinks it looks like 40" from the rear but we are not sure. The only time I will be pulling the teardrop is with the cycle so it will always have a consistent front load. My doorway is 42" from the rear if that helps us figure out where to put the axle.

[bobhenry]

hey hey hey

Maybe we are looking at this wrong ! Make the tongue adjustable .
A tube in tube with 2 or more positions loaded and un loaded. More tongue weight for a better ride use a shorter tongue and a longer tongue when the bike / bikes are on board. Or is it the other way around, Oh well , have the guru's give you a hand with this idea . I would rather build a couple experimental tongues than have to move spring perches and axle positions. Your welder could procede with your best guess at just rear of center and you could adjust later without a huge hassle

[angib]

It looks as though that Little Guy has its axle 48" from the back of the trailer body, so dead in the middle as Madjack suggested. You should never trust Little Guy quoted hitch weights, as they seem to quote the same number for all their trailer models, even though that's clearly impossible.

I've made a few assumptions:
- 8ft long body;
- 5ft long tongue - 3ft wide platform + 2ft A-frame;
- 1500lb trailer including platform;
- no significant galley weight;
- 300lb bike.

Without the bike on the trailer, the hitch would get around 5% of the trailer weight (80lb) - that's dangerously low by US standards (though Europeans would consider it fine), but it is still positive.

With the bike on, the hitch weight goes to 14% of the increased total (260lb), which is spot on the upper end of the recommended range.

If the galley has 100lb of stuff in it, those figures drop to 3%(45lb) and 12%(240lb). So if you want a heavy-ish galley, move the axle to 42-44" from the back of the trailer.

BUT you say your door is 42" from the rear of the trailer, and if that's true, then none of this works. Unless you push the door to the front of the body, as Little Guy have done, you won't get the axle more than 27" from the back of the trailer (unless you go for little wheels). In that case, you'll have 19% of the trailer weight (290lb) on the hitch without the bike, and 27% (500lb) when it's loaded. So while the Tundra may accept that, you'll probably need airbags to help you see over the hood!

Andrew

[sandman]

angib,

Glad you sounded off here since you seem to have the most knowledge about trailers and axle placement. I have included a pic of my profile with some notes to help figure out the best placement of the axle.

Just to clarify, my trailer will be 6 foot 4 Inches Wide with a length of 12 foot. The trailer will weigh in at 640 lbs since the builder suggested using 2x3 C-Channel for the tongue and rails and angle iron for the cross members. The teardrop should weigh in around 850-900lbs. The floor length of my teardrop is 85-3/4" which will leave about a 9" overhang hanging off the very rear of the trailer. The teardrops total length is 95- 1/2". Hopefully this will give you guys some more ideas. The good thing is I have not finalized the placement or size of the doors yet so the profile is still in-tact.



Does this help answer my big 64,000 question. I think 48" from the actual floor for the axle will put it right in the way of the door. This is driving me nuts. The long trailer coupled with teardrop can be done since Little Guy has done it and I am following their specs pretty closely. I just can't get the axle placement worked out on paper or in my head. AHHHHHHHH!!!!!! I am going crazy!!!!

[madjack]

SM, if you're here, your bound to be somewhat crazy...afterall most of us are as well...the new numbers you have given will help and maybe Andrew will chime in as well but I think that your axle should go pretty close to 48" from the rear of the cabin(not trailer frame)...how deep is the front platform and any idea of weight of bike....
madjack

p.s. assuming a 2' centerline(from cabin) on the bike, that makes your "weighted" area around 10' in length...with a 10' tear I would say around 42 to 44 inches...taking in the extra weight of the bike, that pushes out around 46/48"s( my thinking, using the S.W.A.G. theorem )...........MJ

[angib]

That's why I was careful to say 48" from the back of the trailer body! In your case that would be 38" from the back end of the floor.



Add another 15" for the wheel and fender radius (assuming you want 14" or 15" wheels) and you're left with the front 33" of the body in which to put the door - Little Guy have managed to get a couple of inches overlap between the door and the fender, which you might be able to do also.

Andrew

[sandman]

Thanks for all the advice Madjack and angib. You guys are the coolest. I appreciate your time and attention on this problem. Well, it doesn't seem like a problem now that you guys have given me the answer to the question. The trailer will have 14" Alloy Rims.

Madjack-The dry weight of my bike is 235lbs which will probably be stored closer to the teardrop to pull some weight off the tongue. My galley will be pretty much just a storage bin for helmets and riding clothes so the rear of the tear won't bear too much weight. I am trying to think ahead on shaving some weight where possible.

I tried to send an email to Little Guy and got back a canned response and they wouldn't provide technical info on the axle placement just like I figured. They did state that in the current configuration of the Little Guy Sport that they have had no issues or complaints about trailer handling since they went with a wider trailer.

Thanks again you guys for your insight and sound advice. Next round of beers is on me.

[angib]

Revised hitch weight numbers, based on:
- 8ft long body;
- 12ft long total trailer;
- trailer 900lb;
- bike 250lb;
- no significant galley weight;
- axle 48" forward of body rear (39" forward of frame rear);
- bike weight centred 18" forward of body front.

Without bike, hitch weight: 50lb or 6% of 900lb.
With bike, hitch weight: 230lb or 20% of 1150lb.
These estimates are probably accurate to +/- 10%.

Andrew