This is the south-western edge of Bangkok, out where the city stops pretending to be a city and turns into a muddle of canals, warehouses, shrimp ponds and condo blocks on the Thonburi side of the Chao Phraya. Thung Khru and Bang Khun Thian are the districts on the map; Phra Pradaeng, the town that gives the label its name, lies across the river to the east. As a place to begin and end rides north to Ayutthaya or north-east to Khao Yai it makes practical sense, because you avoid crossing the dense middle of the capital twice a day.
Riding here is about patience and awareness rather than corners. Rama II Road, the main artery heading south-west, is wide, busy and lined with lorries, and the side sois are full of scooters doing whatever they like. Motorcycles are barred from the expressways and motorways in Thailand, so you will use the ordinary surface roads, where the leftmost lane is effectively the bike lane and buses swing into it without much notice. Leave before seven on a weekend and the whole city feels more relaxed; by mid-morning on a weekday it is a slow crawl in the heat.
There is more nature close by than you would guess. Bang Khun Thian is the only Bangkok district that touches the sea, a short strip of mangrove coast on the Gulf of Thailand where the city has tried to hold back erosion with bamboo fences and replanting. Across the river, Bang Krachao, the big loop of the Chao Phraya next to Phra Pradaeng, is known locally as Bangkok's green lung: orchards, raised walkways and quiet lanes kept largely free of development. It is a pleasant place to potter about on two wheels at the end of a long day, though the roads inside the loop are narrow and you will share them with cyclists.
Practically, this is ordinary suburban Bangkok, which means fuel stations, convenience stores and noodle stalls on almost every main road. The stores are a good place to buy cold water and electrolyte drinks before setting out. At the finish, after hours on the highway, a bowl of boat noodles at a canal-side shop and a slow ride home with the evening breeze off the river is about as civilised as Bangkok gets.