With the third iteration of the V series SunTour defined the look and performance of derailleurs for the next 30 years. All the elements are here: the curvaceous cast aluminium knuckles, the slant parallelogram, the adjustment screws (clearly marked ‘H’ and ‘L’) at the back, the adjustable cable outer stop, the cable clamped under a washer by a bolt, and the final element - big, glossy, chromed allen bolts.

In this version, the GT pulley cage introduces the form of ‘Quick Cage’ design which SunTour was to use for the next 15 years. Now the outer cage plate is interrupted, making it even easier to fit and remove the chain.

The V GT was not light, but it was an astoundingly affordable, virtually unburstable and frighteningly reliable mechanism that could handle heavy use with a freewheel with a 34 tooth cog - and as such it made comfortable cycling available to millions.

• Derailleur brands: SunTour
• Categories: SunTour - the V story
• Country: Japan
• Date of introduction: 1972?
• Date of this example: 1972 (two letter date code is OL)
• Model no.: 4900 (and also 2900/1)
• Weight: 379g
• Maximum cog: 34 teeth
• Total capacity: 36 teeth
• Pulley centre to centre: 65mm
• Index compatibility: friction
• Chain width: 3/32”
• Logic: top normal
• B pivot: unsprung
• P pivot: sprung
• Materials: aluminium knuckles, steel parallelogram plates and pulley cage plates.