SunTour XC (6300)

SunTour XC derailleur (6300) main image

SunTour’s first mountain bike design, the MounTech had been a masterpiece of technical complexity and sophistication - disastrously let down by reliability problems. The SunTour XC was the second design - and it was all about getting back to basics.

This is a rock-crusher of a derailleur, over-size and over-built in every area. It is as simple as a knife and fork, with one sprung pivot and no fancy features, even the styling and branding is deliberately plain and straight forward.

But despite all this virtuous utilitarianism, I grew to dislike this gear. The smooth outer parallelogram plate scratched visibly - and the branding scratched off - a big problem on a new high-end bike (this example perfectly illustrates this phenomenon). But most of all, the gear change was oddly clunky, imprecise and noisy. As with the aRX, SunTour seemed to have altered their geometry (in the case of the XC the outer cable stop and the cable clamp bolt are attached to opposing parallelogram plates), and the very long pulley cage (with very thin, resonant, steel inner pulley cage plate) conspired to make things worse. This was in marked contrast to the gear change of Shimano’s Deore XT which was becoming silkier by the day.

  • Derailleur brands: SunTour
  • Categories: SunTour - the mountain bike gears
  • Country: Japan
  • Date of introduction: 1985
  • Date of this example: 1986 (two letter date code is CB)
  • Model no.: 6300 (Sutherland’s 6th edition)
  • Weight: 244g
  • Maximum cog: 34 teeth (Sutherland’s 6th edition)
  • Total capacity: 38 teeth (Sutherland’s 6th edition)
  • Pulley centre to centre: 79mm
  • Index compatibility: friction
  • Chain width: 3/32”
  • Logic: top normal
  • B pivot: unsprung
  • P pivot: sprung
  • Materials: largely aluminium, with a steel inner pulley cage plate
SunTour XC derailleur (6300) additional image 01