Please assist
what are the benefits and the weaknesses?
I’m going to do touring on road and off-road (not hard train).
Thx, Dror

Dual wheel takes more weight off the bike.
Single tracks behind your wheels, a big help on trails where there's a narrow portion of compacted earth.

That's the main differences IMO. There's slightly more rolling resistance in a dual wheeled I'm guessing, also another tire to worry about.

Single wheeled might be more aerodynamic, if that matters. They also fight steering input, since you're tilting your entire load.

Though this is from the Quik-Pak trailer website (gonna be biased toward 2 wheel), I own both types and generally find this info correct:

One -wheel trailers:

The one-wheel trailers definitely have the advantage on single-track trails. A narrower trailer is less likely to clip a tree or catch on a shrub. The center of gravity is lower than panniers, making it easier to control the load than it is with a higher pannier setup. With the current one-wheel trailers, low ground clearance may be a problem on uneven surfaces or riding over an obstacle. Placing all the weight on one trailer wheel and the bike means that the bike carries at least one half of the weight. Since a one wheel trailer does not balance the load on its own, the rider must always balance both the bike and the load; making it more difficult to lift the bike and the trailer from a resting position, or to move the bike and trailer while stopped. One-wheel trailers also increase the effective length of the bicycle, creating a machine with a longer wheelbase. This may make the bicycle/ trailer combination difficult to control. Quick maneuvers, crosswinds, or an unstable bike can create high-speed shimmy and make the bike impossible to control.

Trailer and bicycle frame stress can also be an issue with one-wheel trailers. The side-to-side motion created while riding the bike is transferred directly to the frame of the trailer and bicycle; sometimes causing frame struts to break from the metal fatigue created while riding with a heavily loaded trailer.

Hooking up a one wheel trailer is a job for a three-handed individual. Balancing the bike while attaching both sides of the trailer hitch and slipping those little pins into place can be a challenge. It helps to have a strong friend or the perfect wall to support the bike. Heaven forbid that you tour alone or in an area where a handy leaning wall isn't available.

When traveling with the one-wheeled trailer it is difficult to fold and carry, or to store them as luggage. Walking with any one-wheeled trailer once again requires both hands to balance the load and move the trailer. At camp it is simpler to just leave the trailer in one place and tote your gear to and from your tent.

Two-wheel trailers:

A good two wheel trailer can be quickly attached to, or unattached from , the bicycle by any two handed person. Just hold the bike with one hand and pull the self-balanced trailer up to, or away from, the hitch mount and slip it on or off the ball. A two wheel trailer can be easily moved about camp with one hand. With two wheels balancing the weight, the rider never has to lift the weight of the bike and the trailer as a unit. When necessary it is easy to simply drop the tongue without danger of tipping or spilling the load.

Two wheeled trailers may widen the effective width of the bike slightly, however most trailers are about the same as the handlebar’s width and rarely create a problem (you may not be able to store your unfolded trailer in the bathroom). The tongue weight on a two-wheel trailer rarely exceeds one third of the load weight, reducing the adverse effects created by your load under extreme situations. Any weight supported by the bike is supported at, or in front of bike's axle, creating no increase in effective bicycle length.

https://www.quik-pak.com/Bike%20trail...20or%20two.htm

That quote from Quik Pak as pointed out is biased, but IMHO fatally so.

1) Force vector analysis shows that at least 2/3's the weight of a loaded single wheel trailer is on its own wheel.
2) They argue with a pannier straw man. Did you notice?
3) Balancing the BOB/bike combination has never IIRC been identified as an issue. Most report that they have to look back to see if it's still attached.
4) I supposed it's possible, but I never heard of of a frame actually being broken by a BOB. Worry, yes. But IIRC no reported experience.
5) Attaching a loaded BOB trailer is indeed awkward until you figure out how to do it.

The issues with 2-wheeled trailers is that they have, well, two wheels. If you are hugging the edge of the pavement, one wheel is off the road. And when negotiating potholes three lines have to be considered. Having said that, some experienced tourers really love their Burley Nomads.

One advantage of two-wheeled trailers is that they look like they might contain a baby. Some drivers will give you a wider berth for this reason.

A Nomad is set up to track off to the left. In my experience, unless you are riding within 3 inches or so of the shoulder(which is tricky), both trailer wheels will stay on the pavement. I almost never have a wheel drop off the side.

In my opinion, by far and away the biggest advantage of a two wheeled trailer is that the bike will handle almost as if it were unloaded. And the biggest advantage of that is that when you stand, like climbing a hill or whatever, the bike won't wobble and shake like it does with pans or a Bob.

I have the 2-wheeled Quik-Pak trailer and have also toured with panniers. I don't have a Bob, but have toured with folks that did. The BOB was originally designed for off-road riding down single track trails. For that purpose its design makes sense. However, for road riding I find that my 2-wheeled trailer is much more convient then the Bob. It places substanailly less weight on the bike, doesn't impact the handling/balance, is substanially easier to attach/detach, stays upright when detached, and is easy to wheel around camp or hotel. The Quik-Pak is also offset, so riding close to the edge of the road is possible. You do still have 3 wheel tracks, so if an object appears in the road, your chances of hitting it is more likely. Also, at least for the Quik-Pak is that it uses 20in wheels, so tires/tubes are readily available, even at Wal-Mart.

Brian

Thanks for your wise opinions.