In addition to the pony's physical characteristics, the rider's weight, skill level, and experience should also be considered when determining how much weight a Shetland pony can carry. For example, a beginner rider may be more comfortable riding a smaller pony that can carry less weight, while an experienced rider may be able to safely ride a larger pony that can carry more weight.
It is always important to consult with a veterinarian or experienced horseperson before riding a Shetland pony to ensure that the pony is capable of carrying the intended weight and that the rider is comfortable and safe.