Derailleur gears may have been around a long time, but that doesn't mean they can't be improved. French company EGS have tackled the problem head-on: developing radical designs which rethink the derailleur from first principles.
The heart of the system is the Synchro-Shift gear selector, a single spring-assisted twist-grip which operates both front and rear derailleurs in sequence to give twelve gears, in even steps and without duplication. By avoiding the extreme combinations across the block, the chain is kept straighter, it shifts more reliably and lasts longer. Avoiding the 'small-small' and 'big-big' combinations also means that less slack has to be taken up - you can use a shorter chain and a shorter derailleur cage. This reduces weight and further improves shifting per formance and reliability.
The rear derailleur mechanism, thought EGS, was ripe for improvement: vulnerable, fragile, and with awkward cable entry. The alternative is the 'Up-Cage' derailleur, which runs along the chainstay and uses three jockey wheels: two tension the chain, and one controls shifting. The Up-Cage improves ground clearance by up to 9cm (3.5"), and reduces the length of chain required by as much as 15%. This gives considerable advantages in mountain bike racing, keeping the chain away from the dirt, and the mechanism out of harm's way, and has been used to good effect by the EGS racing team. What works on the racetrack will be equally at home in the grime of everyday cycling.
Synchro-Shift gear changers are available in five different versions, and work with conventional indexed derailleurs. Up-Cage derailleurs are designed to take full advantage of the straighter chain provided by the Synchro-Shift selector and are not recommended for use with other shifters.
|