Differences Between 7 Foot Wide and 8 Foot Wide Enclosed Trailers

7-foot and 8-foot enclosed trailers are the same overall width.

For some people, one dimension is very important:

The overall width. Both a 7-footer and an 8-footer are 8.5 feet wide overall, fender to fender.

This is because both trailers use the same width axles, usually dual 3500 lb or more axles.

While you might think you're going to fit in smaller spaces or have more maneuverability with a 7 foot wide trailer, it's only partly true. The swing of the rear of the trailer will be less for a 7' wide trailer and you'll may have slightly more clearance between the front corners and the rear of your truck. However, this can vary depending on the manufacturer.

But the cargo box is different.

The inside of a 7 foot wide trailer is narrower than an 8 foot wide trailer.

Enclosed trailers widths are named for the outside width of the cargo box, although you can think of this as being nominal, just like lumber. (A 2x4 made today isn't actually 2" by 4", it's smaller.)

The inside of an enclosed trailer will typically be several inches narrower than the nominal width. This is mostly due to framing and the plywood and aluminum sheathing.

Fenders stick OUT on 7 foot wide enclosed trailers.

So, the cargo box on a 7 foot wide enclosed trailer is narrower than an 8-footer, but the axle is the same width. This means that the fenders stick out of the trailer on both sides.

This isn't generally a problem, except for a minor issue with barn doors:

They likely will not fold flat against the outside of the cargo box when fully open. Instead, they'll stick out a little bit past the 8.5' width on either side.

Why?

For weight distribution, the dual axles are places fairly far back. The doors need around 3.5' of flat space to fold flat, but the axles and fenders are far enough back that the barn doors will instead contact the fenders and angle out slightly.

While barn doors are usually better than ramps in dense urban areas, this extra overall width when parked is something to be aware of.

On an 8 foot wide trailer, the fenders will sometimes have a small amount of protrusion, or they may be completely tucked into the the cargo box. It depends on the manufacturer. Longer trailers will allow space between the rear of the trailer and the fenders for the doors to lay flush.

Fenders stick IN on 8 foot wide enclosed trailers.

7 foot trailers have smooth interior walls, but 8 foot wide enclosed trailers have wheelwells inside. This is mostly problematic if you want to be able to slide long things agaist the wall of the trailer for storage.

For 7-footers, you can slide things in at floor level. For an 8-footer, you may need to build a shelf level with the wheelwell to store a ladder or sheet goods.

7 foot wide trailers have better driving visibility.

7 foot wide enclosed trailers have more visibility than 8 foot wide trailers, around half a foot on either side, depending on the manufacturer.

Some contractors like the extra visibility since it can make reversing and looking for other vehicles on the road much easier.

On either trailer, it's worth considering buying a backup camera for the rear of the trailer. This will make backing up faster, and more importantly, safer.

8 foot wide trailers have more storage possibilities.

For your day-to-day, one of the biggest differences in both trailers is the interior width. The difference between a 7 foot wide enclosed trailer and an 8 foot wide trailer will be around 8-12" depending on the manufacturer.

This results in a significant higher amount of space in an 8 foot trailer.

For 16 foot long trailers with a comparable height, an 8 footer has around 80 cubic feet more (accounting for the volume of the wheel wells) of interior storage space. This is about 11% more.

That number by itself isn't that interesting, it's really what the extra width gives you. You can:

• Create slot storage for storing sheet goods behind your shelves.
• Create removable storage and use the extra space for heavy-duty, large-item hauling.
• Make a less claustrophobic, wider aisle down the middle of the trailer.
• Have more room for double depth storage. For example, you could store a tote or tool behind another tote.

One problem with 8-foot trailers, however, is that the wheelwells protrude into the storage space. So if you want to store an extension ladder or sheet goods against the wall, you'll have to put them above the wheelwell.

It's easy to make an 8 foot tool trailer heavy.

With the extra storage space, you'll be tempted to keep filling your trailer with more tools and inventory and it's easy to blow past the weight rating. You should think a little bit about your philosophy and strategy.

Many contractors aspire to fit every tool they have in the trailer and also like to be able to do any job. This comes at a price, since you need more organization to support more tools and more inventory.

A typical plywood shelf build in an 8'x16' tool trailer will add around 2000 lbs of plywood weight. This might not sound too bad, but it's a problem:

A fully kitted-out, plywood-shelf tool trailer might weigh around 7000 lbs, a typical dual axle weight rating. If you've sized your truck to pull this weight, you're right on the border of not having enough capacity.

This could mean, for example, that hauling a load of plywood to a job site puts you far over the trailer's weight rating. If buying an 8-footer, you probably want a minimum of a 10,000 lb weight rating.

Some contractors specialize and use smaller trailers, or use a cargo work van in combination with a trailer when necessary.

7 foot wide enclosed trailers are cheaper.

Of course, everything comes at a cost. 8 foot wide enclosed trailers are more expensive, and there's no way around it.

Conclusion

For a most construction contractors, tool trailer width is a big decision. Depending on how you work, how frequently you move your trailer, and your budget, one will be better for you.