East of the river
The eastern half is prairie: long distances, open highway, persistent wind and a very large unpaved road network.
Wind is a continuous load rather than weather. A car being pushed sideways for hours is being corrected for hours, which wears tyres on one shoulder, works the steering rack and tie rod ends under lateral load, and loads suspension bushings to one side. It is why a highway car here can need an alignment without ever having hit anything.
Gravel adds abrasion to everything. Air filters load at rates no service interval anticipates. Grit is thrown continuously at every rubber boot, so a split constant-velocity boot ends a joint quickly. Brake dust plus grit becomes a grinding paste around caliper slides.
Washboard — the regular corrugation that forms on gravel — is the specific killer of dampers. High frequency, small amplitude, mile after mile, which heats the fluid and fades the damping. A pothole is one impact; washboard is ten thousand.
West of the river
The Black Hills are genuine mountains, and the roads through them climb and descend continuously with tight radii.
Descending puts continuous heat into the brakes with no interval to shed it. Pad fade first, as the friction material outgasses; then boiling fluid, because brake fluid absorbs water from the atmosphere over years regardless of mileage and boils lower every year; then a pulsation afterwards from uneven rotor cooling.
Climbing is the cooling system's hardest case: high engine load at low road speed, so there is little airflow through the radiator at the moment it is asked for most.
Cornering continuously loads outer constant-velocity joints, tie rod ends and the steering rack far more than straight-line distance does.
Testing brake fluid for water takes a minute and it is the item that decides how a descent goes. Engine braking is free and it is what the low gears exist for.
Winter, and no inspection
The winter is long and the salting is heavy, so the salt-belt failures apply: brake lines corroding from the outside and failing under pressure without warning, caliper slides seizing, wheel speed sensors bonding into aluminium knuckles.
South Dakota has no periodic safety inspection. Nothing checks any of it on any schedule.
The substitute is a date. Once a year, wheels off, brake lines traced end to end, fluid tested for water, boots checked at full lock, and each wheel rocked at 12 and 6 o'clock. For a used car here that inspection is the whole of the vehicle's history, because there is no other record.
Distance
Between towns the distances are real and help is not close. A weeping water pump at home is a scheduling problem; the same pump on a highway in January is a tow and a night somewhere.
Battery, starter, alternator, water pump, belt and tensioner are the parts worth replacing on age rather than on failure. None are expensive and all of them strand a car.
What the rules and the weather here actually say
- Does this state inspect your car
- The state's inspection programme lasted eleven years, from 1968 until it was repealed in 1979. US Government Accountability Office, read
- Emissions testing, and who is exempt
- South Dakota is one of the states absent from the federal EPA's list of emissions inspection programmes. US EPA, read
- What goes on the roads in winter
- Salt, chemicals and abrasives get used alone or mixed together, and below roughly 15°F the crews switch to sand because the chemicals stop working. South Dakota DOT, read
- The climate, in a number
- Rapid City's normal annual snowfall is 48.5 inches against only 17.44 inches of total precipitation — most of the year's moisture arrives frozen. NOAA climate normals, read
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