Shimano XTR (M900) derailleur

When the Shimano XTR (M900) first appeared I could easily understand what it was. This was a time when Shimano's Deore XT was the undisputed 'best mountain bike derailleur in the world' - and manifestly deserved the title. But Deore XT had its technical roots in the Shimano 600 (Ultegra level) groupsets of the late 1970s. So Shimano's, ever logical, engineers could clearly see a space for an 'ultimate' mountain bike groupset based on superior Dura-Ace technology.

But, if I could understand WHAT XTR was, I struggled with the WHY. Did Dura-Ace's luxury finishes and road racing tech really have much to offer a mountain biker? Put in motorcar terms, would you really want the fragility of Formula One racing car technology in an off-road vehicle? Would you really want the luxury of cream coloured Connolly Leather upholstery when you are wearing a muddy Barbour jacket? I remember reading an interview with one of the designers of the second generation Range Rover who was mildly bemused that he had put so much effort into designing a vehicle that could climb ludicrous gradients in hellish conditions - only for the end customer to turn out to be a dodgy collection of, very urban, Gansta rappers and Russian oligarchs. If you make something that embodies extraordinary contradictions, you may find that you attract a customer who is also interestingly bizarre.

Dura-Ace was not just for folk who wanted to tastelessly flaunt their wealth (although some of those good people did buy it). It was also a genuine racing groupset. But XTR? Apart from those paid to do so, I don't think I saw a single mountain bike racer using an XTR (M900) derailleur in anger. It was just too hideously expensive, too beautifully refined, too tastefully sophisticated and just not down-and-dirty enough. It seemed to be a groupset purely for undeservedly wealthy poseurs, flâneurs and dilettantes - Snoop Dogg and Roman Abramovich probably loved it.

It does look good though - even after all these years.

This is an example of the 'mid length' pulley cage version of the Shimano XTR (M900) - which, for some reason, is explicitly NOT called the (M900 GS).

The vast majority of the XTR (M900) deraileurs that were sold had this 'mid length' pulley cage, with a total capacity of 33 teeth. This is mildly interesting, because the closest ratio M900 chainset was 26-36-46T and the closest ration M900 freehub cluster was 12-28T - giving a required total capacity of 36T. I suppose that the 'pro level' riders who were supposed to be using this equipment were assumed to be disciplined enough to avoid those dastardly cross-over gears.

Or perhaps XTR (M900) bikes were designed to artfully hang on your exposed-brick-New-York-loft wall - and were not to be ridden at all.