Lightweight's small carbon artwork called "RD", which costs 750 euros, is said to be around a third lighter than the top derailleurs from Campagnolo and Shimano. The 120 gram weight of the test specimen, which is suitable for Shimano and Campa ten-speed, is a world record for a standard ten-speed rear derailleur. However, to mount and adjust it on the test bike, we needed a precision screwdriver like those used by watchmakers or opticians.
During the first test rides, Lightweight's lightweight shift box did its job inconspicuously, the shifting behaviour with Dura-Ace components was impeccable, only the aluminium derailleur pulleys run louder than the plastic pulleys of the standard equipment. It is particularly loud when the chain is dry. After around 500 kilometres, two of the delicate rear derailleur bolts were forced to come to a sudden stop as they had come so far out that the rear derailleur almost disintegrated. This could not be repaired on the road due to a lack of tools, so singlespeed was the order of the day. The next 1,000 kilometres with stuck bolts went smoothly. Lightweight has already recognised the problem and current rear derailleurs are supplied with better secured bolts.
Lightweights "RD" is certainly not for cool computers, but it is an option for all those who want as little metal as possible on their super-light road bike.
PLUS: lightest rear derailleur on the market; compatible with mass production technology; precise shifting function
MINUS: expensive
Reference/Info: CarbonSports, telephone 07541/388923, www.carbonsports.de
Photo: Matthias Borchers
