smaller pull behind - single axle VS tandem axle ??

trx680 wrote:
On a smaller pull behind, such as a 18-20ft, whats the advantage of a tandem axle versus a single axle?

I could write a book on advantages for a tandem axle advantages over any single axle on a 18'-20' trailer.

Having pulled both for a living you could not pay me double contract wages to pull a single axle trailer. JMHO

I have had single axle trailers for 14 years -- one blowout -- and that is why I wish I had a dual axle! A blowout on a single axle can be very dangerous.

But I have no choice. I prefer really small trailers, which are always (I think) single axle.

So I watch my tires like a hawk and replace them every few years. (Probably a good idea for dual axle folks, too!)

2 axles provide more cargo capacity, less bouncy going down the highway, straighter tracking (single axle can sway slightly more a double axle), four points of contact with the road surface in lieu of two points of contact when braking.

A single axle, if not overloading the tires, will never overload the tires on any grade. A tandem walking across rough ground, the weight on each tire is always changing.
A tandem is more than twice as likely to have a flat, and is more likely to have damage from the flat tire.
At highway speed, every bump is hit a extra time.

Our 21’ camper weighs 5000 pounds ready to go. I would not want it to be riding on one axle. As it is, there is a comfortable 1000 pound margin from the 6000 pound gross weight.
It also is within specs for it to ride on 14” load C tires, though ours has D tires with gobs of room for weight; something like 3000 pounds.

all of our trailers have been tandems, the 19, 24 and the present 26
had single axle popups years ago
so i cant really state which is better. tandems are more maintenance, twice as many tires BUT
as a casual observation, tandems seem more stable, less sway and bounce on the highway, this just from seeing them on the road. a flat tire on a tandem is almost a non event and changing a wheel is much easier usually(just need to pull or push the trailer onto a block under the good tire
backing up is the same imho but tandems do exhibit tire "scrub" in tight turns which can be disconcerting
overall i prefer the tandem mostly for the redundency

Single axel trailers usually have a heavier rated axel.
My dad and uncle had 70s Airstreams. Identical layout but my uncles was a foot longer, had a double sink. His was a tandem while dads was a single but dad’s had bigger rims And way bigger brakes. The single will back up much easier.

CCC is definitely a concern.

Single axle TTs have about 900 pounds of capacity. My 22 foot Winnie with dual axles has 3220 pounds of cargo capacity. More than a ton and a half.

I like single axles, because when I had tandem axle trailers I had a lot more nail and screw punctures... always in the back tires.

But in an 18'-20' trailer I doubt you'll have enough cargo (weight) carrying capacity with a single axle. Simply filling the water tank might just about put you up to the max. My last couple trailers have been 16'-17' overall. Plus, with a single axle on a 19' or 20'you run the risk of dragging the rear when you go through low spots or up angles (like turning uphill into a gas station or something).

Cargo carrying capacity. The smaller lighter SINGLE axle TT normally use a 3500# axle.
Two tires a side, if you have a blowout, hopefully the remaining tire will allow to limp to a safe place to change the blown tire.