[Pandora]

As an alternative to the Sturmey S2C rear hub as fitted to the TSR2, is the Automatix self -changing 2-speed back pedal brake hub from SRAM worthy of consideration for the TSR2 ?

[Pandora]

I an automatix on order, under £50 including shipping, (Amazon) have ridden a Btwin 24 inch wheeler with the automatix hub , the upshift is very clean and smooth.

I may have to lighten the internal bobweights to raise the upshift point for a TSR2.

[stan ellison]

I’d be interested to hear how you get on with it when it’s all fixed up. I’ve always thought that 3 gears are the minimum. Mid for level, High for down and low for up. Then again I am not an energetic cyclist. I am always happy to free wheel down hill so maybe if the two gears are at the low end it would work. Decades ago I had a splittable Moulton (I forget the proper name) which had the back pedal two gears and brake. It worked fine but I had another bike as my first so it never really got tested.

[Gavin Clark]

Lots of info about the Automatix, including details of how to change the shift point at http://mccraw.co.uk/sram-automatix-review/ and http://forum.ctc.org.uk/viewtopic.php?f=5&t=62320.

For me personally, I can’t really understand an automatic gear shift on a bike. Maybe you have to try one out to get it!

regards

Gavin

[Pandora]

I have ridden a 24 inch wheeler with the Automatix hub, I can report that I found it to be a signiicant improvement on back pedalling gear control.

The shift is controlled by some rotating counterweights, they spin at hub rpm and are are suppressed by a spring, when the critical rpm is achieved, the counterweights overcome the spring and ther upshift occurs,.
The change is near instant, no loss of pedalling momentum or gear slip during the change, all you feel is the load change.

I will keep posting when I get the hub ( which arrived yesterday) laced into a rim and onto the TSR2.

Sram have launched a 28 hole version to supplement the 36.
I think we will see a few more bikes with this hub as word spreads, I paid £48 including shipping from USA to UK for a new boxed item. It is the coaster brake version and cog driver is 3 spline compatible with traditional sturmey hub

[Pandora]

I have the hub and a rim, both are 36 hole

The rim is marked:

Shining Rim A-6N Aluminium T6061-T6
ETRTO 406-21 20″x1.5 MADE IN TAIWAN

Can anyone help by decoding this, I need to know the effective diameter so that I can calculate spoke length tfor an order.

The Automatix is resized compared to a Sturmey S2 hub, diameter of spoke circle does not match

[Author]

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