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Mountain Bike Components

Dating Mountain Bikes by their Components

The idea here (in progress!) is to have a visual map of all mountain bike components available by type, manufacturer & year. Too often date attributions are missing, misleading, or have deliberate misinformation. Compochronology1) allows for a more confident provenance by bracketing possible dates by component manufacture dates. Component dating can disprove claims that bikes are all original and add confidence when everything seems period correct.

Similar timelines have been attempted elsewhere:



Dating Rear Derailleurs

Other than dating headsets and bottom brackets (because they're harder to swap,) dating the rear derailleur is a reliable method to date a bike, as they're very visible and come in a huge array of date limited shapes.

ritchey2.jpg
A Sachs Huret Duopar Eco on a 1981 Ritchey Everest The Ritchey Project

Available in 1981: check. Note that the velobase entry isn't an exact match and its dates are unsure. Looking at other 1981 Ritcheys shows the same or similar specs. Or, looking at other sites such as disraeligears confirms that these were available in 1981.

Chain Wrap Capacity

Mountain bikes need wide gearing to ride both up and down hill. The rear derailleur capacity limits the range of gears and the sizes of the freewheel and crankset. For example, with SunTour MounTech, the first mountain specific component group, the derailleur had a 34 tooth capacity. Pairing this with a SunTour Winner 14-32 freewheel implies that the chainrings can't exceed a 16 tooth difference, such as a 30-46 double. Try and use an older SunTour Cyclone (24T) then the bike would cease to be a mountain bike at all. Today (2021), touring derailleurs have the greatest capacity and mountain derailleurs often have less than 1980's derailleurs.

This page should only list derailleurs commonly spec'd on early mountain bikes or related derailleurs with lots of capacity.

Timeline Date Skew

This timeline starts a few years after the MTB timelime, to be from 1978→1991. The earliest mountain bikes are so rare that dating them by components is a non-issue. When dating a 1989 bike it's helpful to have 1990 and 1991 components on the timeline. Some pre-1978 components used:

Quick links

1995 Paul Powerglide
1995 Paul Powerglide bikemag

By the 1990s mountain bikes had established total dominance of the cycling world. Bike shops once sold 20 mountain bikes for each road bike that went out the door. And this dominance exposed an existential problem – mountain biking was fiercely Californian, forged in the furnace of individuality and exceptionalism that characterises that state – but the hardtail bikes of the time were astoundingly similar to each other. And without exception they were clothed in a near identical suit of Shimano components. Rockshox, Shimano Deore XT and a 7000 series aluminium frame – where’s the individuality and exceptionalism in that?

Enter the Paul Powerglide, the definitive US made bike-porn derailleur of the mid 1990s. It looked amazing: the colours, the CNC geometric shapes, the detailing around the adjustable cable outer stop and the adjustment screws – all of this was like water in the desert for mountain bike aficionados drowning in a sea of lookalike Shimano. The Guardian, 7 June, 2018

Cranksets

Even more visible than derailleurs, cranksets have lots of branding real estate.

Biopace?!? on a 1985 Ritchey Annapurna mombat

Biopace first showed up in 1984 on road gruppos only. It wasn't until 1986 that biopace infected mountain chainrings in the Deore XT group set. However, Ritchey used the road 600EX FC-2606 crankset, back when such things were compatible 2) So, the biopace is period correct. The chainstay mounted u-brakes, however, are very avant-garde for 1985 3). However, there is precedent for Annapurnas to use these: Ritchey DB. So again, period correct.

Component Serial Numbers

Courtesy of https://vintagecannondale.com:

Index Shifting

The 1985 release of Dura-Ace 7400 saw the first index shifting which trickled into every model and brand of rear derailleur over the next few years, requiring new models to support the changing requirements. No rear derailleur on sale in 1986 existed without change by 1989.4) For a history of mountain bike technology, see the tech timeline.

1)
I just made that up
2)
Today, road and mountain components don't get along. See this table on cable pull.
3)
See Sheldon Brown's critique on this doomed fad
4)
SunTour especially suffered a decline with the introduction of SIS and with no decent indexed gruppo of its own, SunTour went bankrupt in 1987, sold itself to Sakae Ringyo, losing focus, reselling itself again and finally closing its component line in 1995. See Sunset for SunTour by Frank Berto.