Repair guides › Wheels & Tires
Look after Presta valves
The tire gives grip and comfort; the tube inside holds the air. The tire bead hooks under the rim edge. Rim tape covers the spoke holes. Pressure is the biggest free upgrade on any bike: wider tires at lower pressure grip and roll better on rough ground; narrower and firmer is quicker on smooth pavement. Presta valves are thin with a lock nut; Schrader are car-style.
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Tools
- Floor pump with gauge: Topeak JoeBlow Sport III ($$)
- Valve core tool: Muc-Off Valve Core Remover ($)
Compare Good, Better and Best for each tool
Steps
- Presta valves are thin, with a small knurled nut at the tip. Unscrew that tip nut until it stops, then tap it once to free the seal before you pump.
- Push the pump head straight on and hold the tire and valve together while you pump, so the valve doesn’t bend.
- Done pumping? Screw the tip nut closed finger-tight and put the cap back on.
- The lock nut against the rim only keeps the valve still: finger-tight. Too tight and it tears the tube at the valve.
- Leaking at the tip with the nut closed? The core may be loose: snug it with a valve core tool (if the valve has a removable core).
- The valve should point straight at the hub. If it leans, the tube has slipped: let the air out, straighten it, pump it up again.
- A Presta tube in a rim drilled for Schrader needs a grommet or adapter ring so the valve can’t rock and tear.
Diagram
Sliced across, like cutting through the tireTire, tube and rim
Signs it needs doing
- Flat (pinch flat = two little slits, "snakebite" = pressure too low)
- Cuts or threads showing
- Bulge in the sidewall (stop riding)
- Squared-off tread on the rear