Trailer spares are made of different materials. The model of your trailer and the recommendations of the manufacturer will weigh on your choices for spares or parts. You cannot and should not randomly choose some alternatives. Finding alternatives is not a challenge. Choosing the right one is. Manufacturers are unlikely to offer you a guide to alternatives since they do not want to fuel any perception that any type of spare or part will be compatible. The compatibilities and recommendations are usually stringent.
When you switch from one material to another, you must ensure compatibility and never compromise on reliability, safety and efficiency. You may find one material to be superior to another. Some people prefer steel over aluminum and vice versa. Some people prefer composites. But all these materials have their suitable applications. Composites are a material system. They are a great substitute for steel and aluminum in many cases but not for all types of trailer spares. The composite design cannot always effectively emulate or mimic the form, shape, strength and structure as well as function of the spare or part made of another material. You need to ensure the choice of material is a suitable alternative, if not better.
Whenever you go for an alternative, material or just model and make, you should use the standards as a guide to know the quality or grade. This is crucial as the grade determines if you can extract the same kind of performance as the original parts or accessories in your trailer. It is not uncommon for consumers to fall for the benefits of alternative materials, even design and the prices can also be a major influencing factor. It is up to you to compare the real merits and demerits so you can make an informed decision. Do not opt for random alternatives without the assurance that they will be better.