A 34/28 on one bike and a 30/25 on another are almost the same gear. Ratios alone will not tell you that; gear inches will.

A pad worn to the backing plate gouges the rotor in one descent, and a rotor is several times the price of a set of pads.

The number on the box tells you how many sprockets there are. It tells you almost nothing about what will work together.

Two seconds with the wheel in the frame tells you whether a hub needs attention. Most people never do it, and hubs fail quietly.

The cassette does not mount to the wheel. It mounts to the freehub body, and that is where most "my new cassette will not fit" problems live.

If indexing works in some gears and refuses in others no matter how you turn the barrel adjuster, stop adjusting. The part you are adjusting is not the one that moved.

Manufacturers rate most 11 and 12-speed quick links single-use, and plenty of people reuse them anyway. Here is what the rating is actually about.

A 25 mm tire on a modern wide rim measures 27 or 28. Every pressure chart you look up was written for the number on the sidewall, not the one on your bike.

Riders self-select a cadence close to their own metabolic optimum without being told. Which makes the useful question not what cadence, but whether your gears let you hold it.

The list of standards is long and the decision procedure is short. Shell width, shell diameter, spindle diameter — everything else is a brand name attached to a combination of those three.

There is no ruler for a cassette. The test is a new chain under load, and the answer arrives within one hard pedal stroke.

Which lubricant you buy matters less than whether the chain was clean when you applied it and whether you wiped the outside afterwards.