Look after bicycle tires and wheels by checking tire pressure weekly, steering around debris, trueing any wobbling wheel and replacing broken spokes promptly, because tires are the hardest part to replace. A worn rim is also a safety matter: at a pressure of 400 kPa a rim 19 mm wide with a 622 mm bead seat has about 14.9 kN of tire pressure acting to push the tire off it.
Part of Bicycle Repair & Fabrication
Tire and wheel care is the routine upkeep of tires, rims and spokes, to extend their life and keep wheels round, tight and safe.
Why A Worn Rim Is Dangerous
A tire inflated to pressure p pushes outward on the rim with a force equal to p times the area it presses on: the bead seat circumference times the inside width of the rim. Take an assumed rim with a 622 mm bead-seat diameter (the common 700C or 29-inch size, recalled) and an inside width of 19 mm (assumed), pressure 400 kPa (assumed; use the pressure marked on your tire):
- Circumference = π × 0.622 = 1.954 m
- Area = 1.954 × 0.019 = 0.0371 m²
- Force = 400,000 Pa × 0.0371 m² = 14,850 N, about 14.9 kN
That force acts to blow the tire off the rim; the bead hooks of the rim hold it. When rim brakes grind the rim wall thin, the wall can eventually crack or bulge under that load, and a tire coming off at speed is a serious crash. Brake Adjustment covers pads worn to their backing, which destroy the rim.
The Routine
| What | How often | Notes |
|---|---|---|
| Tire pressure | weekly | Extending Tire Lifespan |
| Tire surface | each ride | pick out glass, thorns and stones |
| Wheel true | whenever it rubs or wobbles | Wheel Truing |
| Spokes | each ride | a loose or broken spoke shows as a click or wobble: Spoke Replacement |
| Rim brake surface | regularly | for wear, grooves or a concave wall |
What You Need
- A pump with a gauge, if possible
- A spoke wrench
- Tire levers and a patch kit (Flat Tire Repair)
- Spare spokes of the right length
- A truing stand, or the frame and a fixed pointer
Method: A Quick Weekly Check
Step 1: Pressure. Squeeze or measure.
Step 2: Tires. Look for cuts, bulges, embedded objects and worn patches. A cord showing through the rubber means replace.
Step 3: Spin each wheel and watch the rim against a fixed pointer or the brake pads for wobble or hop.
Step 4: Run a hand along the spokes by squeezing pairs: a slack one stands out.
Step 5: Check the rim wall for brake wear, grooves or cracks near the spoke holes.
Common Mistakes
- Riding a rim with a thin, concave brake wall — see the arithmetic above.
- Ignoring a single loose spoke — its neighbours carry more load and fail next.
- Skipping the weekly pressure check — under-inflated tires wear faster and puncture more.
- Overinflating — a tire above its rated pressure can blow off the rim.
Safety
A tire or rim that fails at speed
A tire that leaves the rim, or a rim whose wall collapses, can throw the rider with no warning. Never inflate beyond the marked pressure, replace a rim with a worn-through or bulging brake wall, and keep your face clear of the tire when inflating.
What’s Next
- Learn next: Extending Tire Lifespan — inflation, rotation and liners
- Combine with: Improvised Parts & Fabrication — when tires run out