Road hubs

How to choose a road bike hub

You rarely buy a hub on its own: it is the starting point for a custom-built wheel, or the part you replace when the hub shell is worn but the rim is still sound. Five measurements determine compatibility.

Five things to check

• Front or rear : the rear hub houses the freehub body. It is wider, more complex and more expensive.
• The hub spacing : 12x100 mm at the front and 12x142 mm at the rear for thru-axles, 100 and 130 mm for quick releases.
• The disc rotor mount : Center Lock or 6-bolt. Center Lock is by far the most common in this range.
• The freehub body : Shimano HG, SRAM XDR or Campagnolo, depending on the cassette.
• The number of spoke holes : 20, 24 or 28 at the front, 24 or 28 at the rear. It must match the rim’s spoke-hole count.

The freehub mechanism makes the difference

This is what really sets high-end hubs apart. Chris King uses a helical-tooth system (RingDrive), DT Swiss ratchets (Ratchet), Hope pawls. The more engagement points there are, the quicker the response when you accelerate again — crucial in cyclocross and when repeatedly accelerating, less important on the flat. The freehub sound follows directly from this, and it is more of a buying consideration than many riders admit.

Steel or ceramic bearings

Chris King offers its R45D hubs with ceramic bearings. The efficiency gain is real but small, and comes at a high price; ceramic bearings cope less well with water and road spray. For a bike ridden year-round, a good, well-maintained steel bearing remains the safest choice.

Building a wheel around the hub

A hub, a rim, spokes of the correct length and spoke nipples. Spoke length depends on the hub, rim, number of holes and chosen lacing pattern: calculate it before ordering the spokes, not the other way round.

To find out more: How to lace your wheels

See also: Road wheel spokes · Road bike freehub bodies · Road bearings