The EGS Up Cage was a masterpiece of incredible but doomed euro-technology in the fine tradition of the Concorde airliner and the Minitel data terminal. First find a blind alley, then charge up it at maximum speed, all the while deploying astounding creativity, inimitable panache and a reluctance to compromise on anything, least of all quality.
The Up Cage was a fascinating design. Despite the hypermodernist CNC style, the unsprung rear pivot, rear knuckle, slant parallelogram and guide pulley that does not move with the rotation of the pulley cage are all the children of a SunTour V GT. However, unlike SunTour, EGS did not include the guide pulley in the chain tensioning arrangements at all. Instead they added a separate sprung pulley cage with two tension pulleys. The lower run of chain was close to the underside of the chainstay, ran over the top of the upper tension pulley, through the pulley cage and under the bottom of the lower tension pulley, and then up over the top of the guide pulley. If you have understood all that you are probably French.
EGS claimed that the up-shot of all this cleverness was that the chain length was reduced by 15%, ground clearance was improved by 70mm to 90mm and chain slap was dramatically reduced. All seriously good stuff - and the Up Cage seemed to be genuinely loved by French downhill racers when it first appeared.
Not only was the design classy, the quality of construction was a marvel in its own right. I clearly remember getting a good telling from an EGS employee at a trade show about the shoddy, corner cutting, antics of some of EGS’s so-called competitors. This man, who claimed to be an engineer, despite the evidence of his stylish haircut and fashionable spectacles, maintained that anyone who had progressed beyond GCSE Metalwork knew that titanium hanger bolts should NEVER be seated in an aluminium sleeve. The two metals would catastrophically corrode together etc. etc.. EGS had, of course, lined the sleeve on the Up Cage with a titanium liner to avoid just this problem. It seemed unnecessarily cruel to point out that Campagnolo (the object of his scorn) had sold many tens of thousands of derailleurs which broke his sacred rule - and, while I respected his science, I was not aware of any serious ‘real world’ problems with them - especially if you slapped a bit of Campagnolo’s signature white grease around the titanium bolt.
In addition to its titanium hanger bolt (and liner) the Up Cage has fine sealed bearing races in all three pulleys and even in the cable roller, it has titanium small bolts, it has proper brass (phosphor bronze?) pivots in the parallelogram and, most impressive of all, it has a small, replaceable brass (phosphor bronze?) piece both next to the guide pulley at the point of maximum chain wear and next to the cable roller at the point of maximum cable wear. Sheer class.
When the Martians come, the Up Cage is, most certainly, the derailleur that they will fit on their funny green bikes (while phoning home on their Minitel terminals and flying around in their Concordes).