Bicycle Trailer Capacity: What is the Weight Limit for a Bike Trailer?

​Have you ever wondered how much weight your bike trailer can carry? What factors determine capacity? These questions answered, and more.

The right kind of bike trailer can haul just about anything: people, pets, even serious cargo. But not every bike trailer is built to haul heavy loads.

So, how do you figure out what the weight limit is for a particular bike trailer?

Well, if possible, you should check the manufacturer's specifications first. They’ve tested the limits so that you don’t have to.

But if you can't find the specs, or if you're dealing with a DIY bike trailer, below is a step-by-step guide on how to determine your bike trailer's weight and capacity.

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What is Static vs. Dynamic Capacity in Bike Trailer Capacity?

Every bike trailer has at least two weight capacities: a static capacity rating and a dynamic capacity. Understanding the difference between dynamic and static capacities is crucial for a smooth and safe trip.

1. Static bike trailer capacity is the maximum weight a bike trailer can carry when it’s not moving. In general, static capacity is greater than dynamic capacity.
2. Dynamic bike trailer capacity is the maximum weight a bike trailer can carry that is being pulled by a bike or pushed (in the case of a bike trailer that serves as a stroller).

In the next few sections, we will look at factors affecting static and dynamic capacity.

Factors that affect static bicycle trailer capacity

Wheels

1. Quality tires play an important role if you are loading heavy objects in your trailer. Smaller diameter (16”) wheels require higher pressure than standard 20” with the same loading in the trailer. If you are carrying heavy loads you should consider high pressure tires.
2. Single walled rims are used in almost all bike trailer applications. When fewer spokes are used, double walled rims can be used to compensate. A double walled rim with 36 spokes is used in extreme applications where higher weight capacity is required.
3. Axles used in bicycle trailers are typically 10 or 12mm, or ½”. Use of cartridge bearings improves weight capacity and makes trailers easier to pull.

Frame

1. Single perimeter frames are used in most bike trailer applications. These consist of a perimeter tube around the trailer and an axle tube to connect the two wheels.
2. Double frames are also used around the wheels to support each end of the axle or around the perimeter to disperse the loading of a cantilevered axle.
3. The larger the length and width of the trailer, the stronger the frame must be to support the load. It is always best to load a trailer so the weight is balanced equally front to back over the axle.

Towing assembly

1. The towbar has historically been the most limiting element of bicycle trailer capacity. It is subject to constantly oscillating forces and frequent shocks from collisions with stationary objects. Towbar structural failure could cause the trailer to disconnect from the bicycle.
2. The flexible hitch that completes the connection between the end of the towbar and the bicycle must allow the bicycle to turn freely from the trailer. It also needs to allow the bicycle to lean and lay flat without upsetting the trailer. And lastly it should assist in keeping the trailer upright during sharp turns or side to side bumping such as road curbs. The flexibility of the hitch should diminish as trailer capacity increases.

Factors that affect the dynamic bicycle trailer capacity

Relative Weight

1. The distribution of total weight between the bicycle and the trailer is a critical consideration when attempting to carry heavier trailer loads. The ability of the cyclist to control the dynamics of a bicycle/trailer combination decreases with increasing speed and with the relative weight of the trailer to the bicycle. With speeds under 20 kph the load in the trailer should not exceed 40% of the weight of the bicycle plus rider. This is the reason that Bicycle Trailer Standards worldwide currently advise to limit capacity to 100lbs. It is not the capacity of the trailer but the ability of the bicycle to stop the trailer that is the determining factor.
2. The use of trailer brakes can ameliorate the relative weight issue but can’t resolve it completely. With the advent of electric bicycles the desire to carry greater loads will continue. These increases in loads should be shared on both the trailer and the bicycle. A heavier bicycle will help to control a heavier trailer.

Height of Load

1. Trailer tipping due to high loads, uneven ground, or fast turns is common. Wider wheelbase, lower center of gravity, and slow speeds increase dynamic stability. 

• Generally, it is safest to keep your cargo height to a maximum of 1.5x your trailers' full width.

Find the Best Bike Trailer for You

Not every bike trailer can carry heavy loads, but the right kind can haul just about anything! Browse our selection to learn more about our bike trailers, and feel free to contact us with your questions about bike trailer weight limits and more.