By 1989 it was more than clear that MAVIC needed a replacement for the venerable MAVIC 801/851series. The Shimano Dura-Ace SIS (7400) had been launched in 1984, and index shifting was spreading through the pro peleton like wildfire. More importantly, Shimano was making index shifting available at lower price points, and consumers were starting to see it as the norm.
MAVIC's response was to create a Shimano Dura-Ace SIS (7402), but with French characteristics. The derailleurs were manufactured by Simplex, loosely based on their Simplex Vallée model, but MAVIC breathed on the detailing. The derailleurs were completely demountable, the finish on the castings was higher (if not to Shimano Dura-Ace standards), there were lots of, nicely machined, stainless steel small parts, bizarrely, the pulley wheels had needle roller bearings and finally there was the signature hard anodising of b-pivot bolt, parallelogram plates and pulley cage plates. Ah, and I almost forgot, they were also reassuringly expensive.
The styling was clean, simple, refined and modern, but it lacked the enticing eccentricity of MAVIC's earlier models. These derailleurs are quietly nice, but far from heart-stopping.
The MAVIC 840 series was offered with three different lengths of pulley cage:
Which brings me to the naming convention. Complete the number sequence: 800, 850, XXX. Does 840 spring to mind? Would 900 not seem more natural? How about if the 800 series was launched in 1979 for model year '80, and the 850 series was launched in 1984 for model year '85, what would you call a series launched in 1989 for model year '90? Does 840 spring to mind? Would 900 not seem more natural?
And why is the short cage derailleur for double chainsets the 840, the longer cage model for triple chainsets 841, but the very long cage model for mountain bikes the 845? What is it about 842 that would be so wrong? Simplex were the masters of a confusing naming conventions - and MAVIC seem to have been infected with their disease.
In 1992 photos emerged of this version of the MAVIC 840 - silkily anodised silver, with a cutout in the outer parallelogram plate at the tension pulley. It appeared on various team bikes at that year's Tour de France.
Some of its key features may be:
It has been suggested to me that MAVIC had decided to move away from the largely black components of the original 840 series towards a more light grey/silver look for the upcoming radical, electronic, MAVIC Zap groupset. I have some sympathy for this view because the very earliest, almost pre-production, Zap that I have is very dark grey, but the mainstream production Zaps were changed to very light grey. A silver 840 would then be a more economical (and less risky) option for MAVIC to offer alongside the Zap.
Finally there is the mystery of the steel inner pulley cage plate. I have two thoughts on this: