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Vehicle Knowledge · Topic 3 of 6 · ~1 min read
Tyres: The Only Part Touching the Road
Everything the last lesson said about brakes, and everything Module 4 said about stopping, is finally spent through four contact patches each the size of your palm. The tyre is the only part of the car that touches the road — so its condition is the ceiling on every other safety system. This lesson reads a tyre the way it asks to be read: the tread ladder and where "legal" stops meaning "good," the sidewall code, why heat (not wear) causes the highway blowout, and the two faults you can feel through the wheel.
In this lesson you'll learn
- The tread ladder: what new, worn, and legal-minimum tread each mean for wet grip — and where the wear indicators hide
- How to read a sidewall: what 235/65R17 98H and a load index actually say
- Pressure: why both under- and over-inflation harm you, and why heat is the Kenyan multiplier
- The two fault signatures every driver should recognise from the steering wheel: pull and vibration
- 1. The Tread LadderRead the tread ladder, distinguish "legal" from "good" wet grip, and find the tread-wear indicators.
- 2. Reading the SidewallDecode a sidewall marking and identify the two figures that are safety ceilings — load index and speed rating.
- 3. Pressure and HeatExplain why both under- and over-inflation harm you, why heat is the Kenyan multiplier, and how to check pressures correctly.
- 4. Faults, Replacement Rules, and SparesRead the two seat-of-the-pants tyre faults, apply the replacement rules, and treat spares for what each one is.