MAVIC 840 prototype (?) derailleur

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:

The MAVIC 840 with a 46mm cage.
The MAVIC 841 with a 70mm cage 'for triple chainsets'.
And a later addition of the MAVIC 845 with a 75mm cage for 'mountain bikes'

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.

I believe that this is a prototype of the MAVIC 840.

Some of its key features may be:

The parallelogram plates are anodised black.
The outer pulley cage plate is anodised black. It has no cut-out at the tension pulley.
The inner pulley cage plate is also aluminium and also anodised black. It also has no cut-out at the tension pulley.
It has a a very Simplex arrangement at the b-pivot. The allen bolt screws in from the inside of the hanger. The outside is smooth, domed and disturbingly weird.
There is no external b-pivot adjustment screw. However the spring tension at the b-pivot can be adjusted using an Allen-headed grub screw mounted in the body of the b-knuckle.
The cable adjuster is aluminium and black.
The pulleys are black (not grey) but with the signature needle roller bearings. Also, very unusually, they are branded 'Simplex', not 'MAVIC'.
The pulley bolts and adjustment screws are steel.
The pulley cage spindle is locked into the p-knuckle using a long, thin, Allen bolt.

The strange arrangement at the b-pivot has some history to it. From the 1950s Campagnolo Gran Sport onwards 'quality' derailleurs had featured a large Allen bolt at each of the b-pivot and p-pivot. But in 1987 Shimano introduced the Shimano Santé and in 1988 Simplex followed up with the Simplex Vallée. Both appeared with, rather svelte, concealed p-pivot bolts - setting a new fashion for how a 'modern' derailleur should look. By this point in their history it was unusual for Simplex to be a style leader, so, for 1989, they decided to take the trend a step further and they also concealed the b-pivot bolt. Unfortunately the result was anything but svelte, as we see with this example, and, thankfully, the idea never caught on.

Like most of the prototypes in this collection, this derailleur has had exceedingly heavy use. I always find it slightly surprising that prototypes get to cover so many miles, but it is very heartening.