Bike spokes: tension, replacement and truing

Why spoke tension matters so much

A bike wheel is a balance of tensions. Each spoke pulls the rim toward the hub with a precise force. If a spoke is too loose, the wheel goes out of true. If a spoke is too tight, it risks breaking or cracking the rim at the eyelet.

The ideal range: between 80 and 130 kgf (kilograms-force) depending on the wheel type. Road wheels are generally tighter (100-130 kgf) than MTB wheels (80-110 kgf). The drive side is always tighter than the non-drive side — this is normal and necessary.

Measuring tension: the tensiometer

The Park Tool TM-1 is the workshop standard. You place the spoke in the clamp, read the deflection on the scale, and convert to kgf using the supplied chart (which depends on spoke gauge — 1.8mm, 2.0mm, etc.).

Method without a tensiometer: squeeze two parallel spokes between your fingers and compare the flex. This is not precise, but it detects an abnormally loose spoke. You can also tap spokes with a wrench — a tight spoke produces a high-pitched note, a loose one a dull note.

The goal is not for every spoke to be at the exact same tension, but for the variation between spokes on the same side to not exceed 20%. Uniformity matters more than the absolute value.

Truing a wheel: the quarter-turn technique

Truing means correcting the lateral (wobble) and radial (hop) deformations of the rim by acting on spoke tension.

Fundamental rule: turn spoke nipples by quarter turns maximum. The more you turn at once, the more you risk creating a flat spot or unbalancing the tension.

Procedure:

1. Place the wheel in a truing stand (or flip your bike and use the brake pads as a reference)
2. Spin the wheel and identify areas that deviate laterally
3. If the rim moves right: tighten the left-side spokes OR loosen the right-side ones (quarter turn)
4. If the rim moves left: the opposite
5. Check radial hop (the rim going "up and down") by adjusting spokes in the affected area
6. Alternate between lateral wobble and radial hop until satisfied

Acceptable tolerance: less than 0.5 mm lateral wobble for a road wheel, less than 1 mm for an MTB wheel.

Replacing a broken spoke

A broken spoke is replaced individually. But watch out for the type:

• J-bend: the spoke has a 90-degree bend that hooks into the hub flange. This is the most common type. You can replace it without removing the cassette if it is a non-drive-side spoke.
• Straight pull: the spoke is straight with a special head that inserts into the hub. Stiffer, less fatigue at the bend — but impossible to replace without disassembling the hub if the flange is closed.

Replacement steps (J-bend):

1. Remove the tire, rim tape, and inner tube (or tubeless)
2. Remove the broken spoke nipple from the rim side
3. Remove the broken spoke through the hub flange
4. Insert the new spoke following the same lacing pattern as its neighbors (2x, 3x...)
5. Thread the nipple by hand, then gradually tension
6. True the wheel following the method above

Common mistakes

• Over-tightening at once: you would create a localized flat spot and over-tension that breaks other spokes
• Ignoring the side: the drive side is always tighter. Do not try to equalize both sides
• Not lubricating nipples: a drop of oil or light threadlocker on the threads makes adjustment easier and prevents seizing
• Forgetting the rim tape: after any spoke work, make sure the rim tape fully covers all spoke holes

Try L'Atelier free for 10 days — no credit card required.