A "Spec & Build" Bike.
Built bikes. Built bikes are normally built up in such a way to accommodate majority of riders. For road bikes, this would mean compact cranks and an 11-28 cassette. For mountain bikes, cranks would either be triple or double, and paired with a wide range 11-34 cassette. Although, nowadays, mountain bikes spec'ed with single chainrings (or 1x - "one-by") are becoming more popular.
- Drivetrain. These rarely have "straight" groupsets (except for the higher end models). There are always parts from another groupset of the same manufacturer or from a different brand. For example, when manufacturers quoted a bike as having a "Shimano 105", what I got were Shimano 105 shifters, front derailleur and rear derailleur. The crankset is a non-series model from Shimano and the cassette is Shimano Tiagra (one level lower than 105). Because these are not as complex as the shifting mechanisms, these substitutions have hardly any recognizable effect (see our article about mixed groupsets). The brakes are unbranded.
- Wheels and Cockpit. These components are usually supplied in-house - by the frame brand itself. Another possible supplier would be a subsidiary or sister company of the frame manufacturer. For example, when I got my Giant Defy, the wheels and tires are from Giant. The whole cockpit - stem, handlebar, bar tape, seatpost and sadde - are also wholly provided by Giant. Essentially, the whole bike except the drivetrain are produced by Giant.
