Shimano Parallax - what does it mean?

[sam_white]

In 1994, Shimano introduced Parallax hubs to the XT groupset. They were also available on many other groups around the same time until the late 1990s.
As far as I'm aware, the difference was a larger hub body.
But what does 'Parallax' mean and why did Shimano decide to use that word?

 

[Guinessisgoodforyou]

https://en.m.wikipedia.org/wiki/Parallax

 

[doctor-bond]

The axle has a fatter 10mm middle section and standard 9mm ends, so ….. if an observer were to look at the axle from the side ….…. Nah, I bet the marketing meeting where they came up with the name was in 1993, and one of them was hooked on Wayne’s World released the previous year:

 

[Suprachrgd82]

The trend at that time was a large hub body, straying away from the traditional hyperbola, to add strength and rigidity for suspension forks….a fat hub body that runs parallel to the axle. I vaguely remember reading this in Mountain Bike Action 30 years ago. I can’t remember what I had for breakfast this morning, but my brain retained that tidbit of uselessness. *shrugs*

 

[Aech]

Keeping it simple, if you look at a non-disc front wheel then the flanges on the hub are equally spaced either side of the hub's center line so the spokes end up being exactly the same length with the same tension when the rim is trued properly.

However with the rear you tend to get longer spokes on the non-drive side (with less tension in them) and shorter spokes (with higher tension in them) on the drive side because the cassette means you have to move the drive side flange nearer the center line of the hub.

Parallax moved the non-drive side flange in to match the cassette side so the spokes would be under similar tension



This is a simplified version of the truth as most bikes have the drive side dropout a little further away from the frame's center line than the other to create more room for the cassette.