Cavalry Light Maxim Gun, 1901
The Cavalry Light Maxim Gun mounted on a trike, 1901 British Trials. As a combat vehicle it was trialled as an option to give cavalry mobile rapid firepower, but it was not adopted by any militaries, as when the trike is moving, the weight of the vehicle's guns and 400 (light load) or 1000 (combat load) rounds of ammunition per gun made it virtually useless on any terrain that was not a good clear path or on a plain or other similar open ground, meaning that normal cavalry or other bicycle mounted troops were much more mobile during the trials. (1)
With the vehicle stopped, when trying to fire the machine guns, the weight and the necessary rigidity of the structure that supported them caused tremendous vibrations that made any attempt to aim with the Maxim's already rather poor sights almost impossible.
Another complication was the weight of the vehicle, as with even the lighter Cavalry variants of the .303 British calibre Maxims the trike was around 170 kilograms or 375 pounds with a full ammunition load in the boxes underneath the trike. As a result it struggled climbing hills, but was able to be towed by bicycle infantry troops or horses in emergencies.
Here you can see the cavalry Maxim Trike in it's 'Deployed' state better, with support struts down to try and prevent vehicle movement or rocking. The trials were conducted by the 26th Middlesex Cycling Volunteers at the Royal Military Tournament. (2)
A modern replica of the trials Cavalry Trike constructed post 2008. It uses a slightly different frame and has larger ammunition crates than the original, as well as non-functional guns.
1- https://www.forgottenweapons.com/hirams-extra-light-maxim-gun/
2- Scientific American Magazine, (1901)