New Items
Sturmey Archer A2H automatic 2 speed gear hub for Brompton
New Release!
Avaialbe only in Black 28H
Avaialbe only in Black 28H
Introduction Spec
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The Sturmey Archer Automatic A2H is a great hub for the city. It shifts automatically according to the speed**, and does away with the shifter and gear cable for some weight saving and a cleaner look. And most importantly, the hub runs ultra-smooth and the shifting is crisp.
This hub can be fitted on all Brompton except for the G line, including the A/C/P/T lines, pre-2021 M/S/P/H models, as well as the short wheel based Brompton made before 2004. It is a drop-in replacement of existing wheel/hub. No frame modification is required. On the A and C lines, and all pre-2021 models, it will require an axle extension nut (included in the kit) to secure the chain tensioner.
**This hub shifts automatically at an angular velocity of approximately 3 m/sec or 11 Km/hr in a 16” wheel. In more intuitive terms, when used on a 16” wheel Brompton, with a 15T sprocket and a 44T chainring, this hub will shift automatically at around 50 cadences, (50 crank revolution per minute, just a little slower than 1 turn per second). With smaller sprockets or larger chainrings, the shifting cadence will be slower. For further information, please see the shifting cadence chart in the reference section.
The hub is offered with 2 choices of driver/freehub body, as follow
1. Standard 3 spline driver– supplied with a choice of 13/14/15T 3/32”sprocket
2. Standard 9 spline driver – supplied with one 3/32” sprocket and one 1.9mm (9s) sprocket, i.e., the same configuration as Brompton 2 and 6 speed bikes. You do need to have the factory 2 speed shifting mechanism pre-installed to utilize the two sprockets.
Hub Information:
Automatically shift at rotational speed of 3 m/s, or a linear speed of 11.1 km/h on a 16” wheel.
Gear Ratios: Gear 1: 100%, Gear 2, 137%
Overall Gear Range: 137%.
Axle length 146mm
OLD: 112-113mm
Flange PCD 67mm,
Hole Count: 28H
Spoke Hole Diameter: 3.0mm
Flange to End Distances: NDS 42mm, DS 33mm
Weight (hub only) : 950g ± 5g
Package content:
- Hub assembly
- Lock nuts, non-turn washers, extension nut,
- Sprocket(s), 1 or 2 depending on the choice of freehub
Available sprocket size for 3 spline driver: 13/14/15T
Available sprocket size combination for 9 spline driver, 12/17, 13/17, and 14/17T. Choose 12/17T for greatest gear range, and 14/17 for more even steps
Recommend using smaller chainring, such as 40T or 44Tchainring.
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