External Wheels or Wheel Wells

[travist]

Hi All,

As mentioned in other threads, I'm building a standy tear drop, fairly big actually (15.5' long, and 7' wide). I'm going to do a tandem, but if I do, the wheel wells would be large and take up a good chunk of potential storage for us, but doing deck over is too high for the galley kitchen (at least I think it is, unless there is a good solution out there.)

So, just in general, what are the advantages and disadvantages of the two approaches. Aside from width should I avoid external wheels? it seems like a good solution to my problem. Is there other disadvantages from making wheel wells aside from chewing up my storage space?

Is there any towing considerations that I should consider with either?

Thanks,

[pchast]

Why tandem? What is your projected final weight?

[travist]

Two biggest reasons I want tandem.
1. Tire redundancy. My parents have had their trailer tires blow out on the highway with reasonably new tires, and I know you can lose your trailer that way.
2. Tracking/driving, it would track smoother.

But either way I'm curious about the wheel wells, because even if I went single axle, I still feel like you lose a fair bit of space for wheel wells.

[swoody126]

¿ is 7' wide your intended box size or your total width (incl fenders) ?

a 7' wide box plus external fenders puts your footprint width out to about 102"± leaving 7' of inside floor width

a 7' wide box w/ fender wells inside will cost you a bit of storage/living space(6cuft± on each side) and reduces your central floor width to about 5'±

either way a 7' wide box on tandems presents quite a frontal surface to tow into the wind specially if it is a full standee

having towed a 7x14 box w/ outside fenders i can tell you that even empty it CAN be quite a load in windy situations even behind my F-350

with it loaded w/ my sidecar m/c and gear it simply became HEAVY

just points to ponder...

sw

[Ottsville]

Two biggest reasons I want tandem.
1. Tire redundancy. My parents have had their trailer tires blow out on the highway with reasonably new tires, and I know you can lose your trailer that way.

This is also something I think about, but keep in mind that with a single axle you can run LT tires which, in general, are a better quality than ST tires.

2. Tracking/driving, it would track smoother.

There's no reason there should be a *significant* difference between a single and and double axle based on that alone. Sure they will be a little smoother, but tracking and driving are more affected by loading and length from ball to axle.

But either way I'm curious about the wheel wells, because even if I went single axle, I still feel like you lose a fair bit of space for wheel wells.

So the width is an interesting question. Though I've never known anyone to be ticketed for it, some states have an 8' limit on trailer width except on designated roads where you can run 8'6" trailers.
https://www.rvtripwizard.com/rv-info/state-road-laws.php
https://rv-roadtrips.thefuntimesguide.com/rv_size/
So with a 7' trailer and fully outside tires, you could be over 8'

Personally, I like trailers that are slightly wider than the TV whether that be at the walls or the fenders. They are easier to see yet you can still see around them. Yet a narrower is better for driving through towns and off-road/forest service roads and camping in undeveloped areas.

With a wheel well you have lots of options. You could make it any height you desire and tires don't need to be fully recessed under the wall. You can do a hybrid of partially recessed and fender.

What is your projected final weight?

This is a good question to answer. It may help you with the tendency to overbuild.

[tony.latham]

Hmmmm....

Trailers are double-axled for hauling heavy cargo. Not for tracking and not for tire redundancy. You have to put trailer tires on double axles because they need to have stiffer sidewalls because of the stress put on them while turning tight corners. Cheap Chinese trailer tires are famous for failing.

Put a good set of LT radials on a single axle trailer and they'll come apart as often as they do on your tow vehicle. And they'll ride better. Your trailer will track like an arrow as long as you use the 60/40 rule with axle placement.





Tony

[working on it]

Hmmmm....

Trailers are double-axled for hauling heavy cargo. Not for tracking and not for tire redundancy. You have to put trailer tires on double axles because they need to have stiffer sidewalls because of the stress put on them while turning tight corners. Cheap Chinese trailer tires are famous for failing.

Put a good set of LT radials on a single axle trailer and they'll come apart as often as they do on your tow vehicle. And they'll ride better. Your trailer will track like an arrow as long as you use the 60/40 rule with axle placement.





Tony

• Exactly! What he said.
• I have had blowouts/shredding/tread separation on my tandem axle-ed car hauler, but they were due to: 1)old, worn-out tires, 2)tire damage caused by bent axle, 3)over-speed while over-loaded, 4)road debris, and 5)cheap no-name Chinese tire tread separation. I could've avoided most of these occurrences if I had possessed the money to repair the bent axle, or to put good tires in place of bad ones, but at the time ALL my spending money was going into my drag racing car, instead. The road debris was pretty much just unavoidable, though.
• After many years of trailering, mostly tandem axle trailers, I was hesitant to go to a single axle, citing the same reasons the OP listed: tire redundancy, and possibly a smoother ride (over bumpy roads), but used what I had to start a "cheap" TTT project, a derelict single-axle trailer. Along the way, I've improved it enough, and proven its' durability, so that I figured it was time to install the best tires available for using it (IMHO), to eliminate the weak link, my 12-year-old ST tires.
• I was unable to find another ST tire replacement that I trusted, so I went to LT tires, which I have used for many years on my HD pickup.
• LT tires have toughened, stiff sidewalls, better/deeper tread than ST tires, and last longer due to higher standards imposed in their manufacture (they are meant for use on pickups, where they are used for steering (and trailing) use...which tends to put much more strain on a tire's carcass than simply following). Take a hard corner at high speed, and think of how great the forces are, on the leading tire! To paraphrase what Tony said: put a good set of LT tires on a single-axle trailer, and you're good to go!

[travist]

I have a fairly curved front, which should help with wind load, so not really a box in that sense.

I don't yet have a projected weight, but I'm definitely keeping it under 3500# wet.

You all have given me a lot to think about. In canada we can do the 102" width no problem, but its good to know that some states don't allow that.

I still think even with good tires, in that off chance I blow one tire, I see the whole trailer flipping and losing all my hard work, maybe that is unnecessary fear though.

Thanks for all the insight!