When adding a component to a bike under My Gear it is necessary to select the component type from a drop down menu but many components don't match the default types. When this happens I select the closest match but each type can only have one active component so the chosen type is then unavailable for future additional components.
For example, last year the hub shell on my rear wheel was replaced. There is no type option for hub shell or even hub so I selected "Rear Wheel" as the component type. Last week I replaced the mudguard on my rear wheel. There is no mudguard component type and "Rear Wheel" is already spoken for so I have logged this against my "Front Wheel".
A simple solution would be to add a type called something like "Other" that can be used for multiple components. But maybe also reconsider the restriction that there can be only one of any type of component.
BTW, this is a similar idea to Manage multiple wheelsets in Strava Gear though my idea is more generic than just wheelsets and would be simpler to implement as it does not require linking components to more than one bike.