Freeze-thaw at its worst
A pothole is water that got into a crack, froze, expanded, broke the surface apart, then thawed and let traffic finish the job. The damage depends on how many times that cycle repeats, and Missouri sits in the band where it repeats the most: cold enough to freeze regularly, mild enough to thaw between times.
Kansas City and St. Louis are the visible result, and city streets take it worst because they are patched rather than resurfaced.
The suspension absorbs all of it, and the energy does not stop at the wheel:
- Wheel bearings. A sharp impact brinells the races — small indentations at the points the balls were loaded against. Silent that week, rumbling three months later.
- Steering geometry. Camber and toe move when a control arm or a strut takes a hit. The symptom is a pull, or a wheel that tramlines, or a tyre wearing one shoulder.
- Control arm bushings. Rubber tears under shock loading rather than wearing out. Clunking over expansion joints with vague steering either side of centre.
- The strut itself. A bent rod binds. It shows as a knock on rebound and a car that never quite settles after a crest.
- The wheel. A rim bent against the edge of a hole holds air and looks fine, and produces a vibration that survives every rebalance because balance was never the problem.
An alignment after a significant impact is part of the repair rather than an upsell. The geometry moved when the component did.
The inspection finds it
Missouri requires a safety inspection on a two-year cycle for most vehicles, with newer ones exempt for an initial period, plus emissions testing in the St. Louis area.
Given the roads, the failures cluster in exactly the places above: suspension on play or a leaking damper, tyres worn unevenly because the alignment has been wrong since an impact, and brakes on thickness or on uneven wear from a seized caliper.
Two years between inspections is long enough that a pothole in February can have destroyed a set of tyres before anybody looks. Checking alignment after any hard strike is the cheap version of that.
Salt underneath all of it
Winter salting is heavy, so every failure above happens to a car whose underside is also corroding. Brake lines corrode from the outside and fail under pressure without warning; caliper slides seize; wheel speed sensors bond into aluminium knuckles.
The buying rule follows: in this climate the removal is the expensive half of a job, so the complete assembly usually beats the component.
The Ozarks, and storms
Southern Missouri is genuinely hilly and the roads corner and climb continuously, which loads brakes on the descents and outer joints through the corners.
Missouri also gets damaging hail most springs. The panels get claimed; the parts that fail afterwards are the lamp lenses, which crack without shattering, take in water, and fail properly weeks later.
Checked