What is a Calthorpe?
There are certainly names in motorcycling that are more common than others. Ask just about anyone, motorcyclist or non-motorcyclist, to name a motorcycle manufacturer, and you’ll likely hear some common responses. Those responses are likely based mostly on how long a company spent in the manufacture of motorcycles and how many bikes the company produced.
Even when it comes to British motorcycles, the most likely answers to the same question will probably be Triumph or BSA. It’s not too likely that you’ll have someone give you the name “Calthorpe” when you ask them to name a British motorcycle manufacturer.