In the early 1980s SunTour launched their 'Tech' series of highly advanced derailleurs. We were stunned and amazed at the sheer sophistication of these engineering wonders.

But we soon were equally stunned and amazed that SunTour, a brand that had made reliability its watchword, had launched products that broke so quickly and frequently. When they worked they were great - but many soon stopped working.

This image shows some parts from 1980s SunTour 'Tech' series derailleurs that have failed in very typical ways:

• First up are two typical, wrecked, guide pulleys. One of the pulleys has frozen and the teeth have broken off. The other pulley has continued to turn, but too stiffly, and the teeth have been ground down to stumps.
• Second is a 'parallelogram' wire from the sealed body of a Superbe Tech derailleur that has failed. It has straightened at one of its bends, no longer engaging with the flange attached to the relevant knuckle.

• Publisher: SunTour
• Country: Japan
• Date: 2025
• Derailleur brands: SunTour
• Derailleurs: too many to list here