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Sram Automatic 2 Speed Hub

4.4 Stars 5 Reviews

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120mm x 36 Hole (Coaster Brake)

Available to ship
All Warehouses16 - Dec 18th
32 - Dec 22nd

pickup_biking_man Available for pickup
Portland, OR0 - Dec 18th
   If ordered now...32 - Dec 22nd
Ogden, UT0 - Dec 18th
   If ordered now...2 - Dec 19th
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130mm x 36 Hole (Rim Brake)

Available to ship
All Warehouses39 - Dec 18th
39 - Dec 22nd

pickup_biking_man Available for pickup
Portland, OR0 - Dec 18th
   If ordered now...39 - Dec 22nd
Ogden, UT0 - Dec 18th
   If ordered now...24 - Dec 19th
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Current Customer Rating

4.4 out of 5 (5 ratings)

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Customer Reviews

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Far more versatile than a singlespeed hub, but dead simple and solid

I got this for my folding bike so that I would have more than 1 speed on Portland's hills, but since this is my just-get-on-and-pedal super simple bike with dynamo lighting, I wanted something with clean cable-free installation and operation, and no shifter. Naturally, for this application I got the coaster-brake version. I am starting to suspect that it has a bit of extra drag, as mentioned by a previous reviewer, which is a shame but OK by me because this is not my fast-commute bike (smaller wheels are slower anyway, at least with typical widely-available tires).

The shifting is mostly great, instantaneous and silent. Since this is my super-automatic bike it's very cool to have it automatically pick a higher gear for higher speeds and a lower gear for lower speeds. One glitch is that in my experience it OFTEN upshifts on bumps at speeds below the shift point, forcing me to stop pedaling for a split second so it will shift back down.

The other problem, as everyone else has mentioned, is that the shift point is at too low of a speed. This is especially true for me with 20" wheels, and it shifts at just over 8 mph. I've considered opening it up and trying to adjust the spring, but it's not really that bad for me since I've geared it fairly low, so I can climb some hills and don't really need to go that fast on the flats with my putter-around bike.

I may upgrade the folding bike to a 3-speed, which is less simple in operation but is better on our big hills and may have less drag. In that case I'll give it to my kid, who's currently on a 20" coaster-brake singlespeed, would surely love a second gear, and won't mind the drag.

Pros: Simple setup, no cables! Mostly works great. Smooth and silent. High gear doesn't seem less efficient than the direct-drive low gear. Weight very reasonable for a multi-gear hub with a built-in brake. Other than the ghost-upshifts on bumps it works great and isn't flaky or breaky like I've heard about the Sturmey 2-speed hubs.

Cons: Will upshift on bumps. Shift point lower than optimal. Maybe a bit of extra drag in the coaster-brake version.

Would Buy Again: Yes
Would Recommend: Yes

Reviewed on: June 12, 2014
Reviewed by: GlowBoy

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Great once shift point is adjusted

I have two of these, one I built into a 20" wheel for a folding bike, and one in a 700 wheel. The hub shifts seamlessly and gives 2 gears, the average of which would be a common singlespeed ratio, depending on your setup. The coaster hub version is heavier and has more friction than the freewheel version.

The only problem, and it's a big one, if you don't want to disassemble the hub, is that it shifts too early, dumping you into the harder gear at the worst moment, such as when climbing a slight grade, when it's probably more pleasant to just spin a bit. For me, this defeats the whole purpose: to have a ratio for climbing and a ratio for descents and flats.

I've adjusted both of mine to shift around 13-14mph and I really like this hub once it is adjusted. This requires opening it up and either resetting the spring tension, or winding a new spring. If you search, you'll find posts about this.

Pros: Feels like a singlespeed but with 2 ratios
No cables/clean appearance

Cons: Heavy
Occasionally shifts if you hit a bump

Would Buy Again: Yes
Would Recommend: Yes

Reviewed on: April 13, 2014
Reviewed by: Jon

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I rode this without any modification on 650B wheels with a 40 tooth chain ring, and shifting occurred absurdly early. Maybe it's designed to be used at a lower gear ratio.

If you want to adjust the spring tension you'll need a 22mm cone wrench to pull apart the hub and a set of fine needle nose pliers for removing the weight retaining clip. A stitching needle is also handy for holding the spring arm when you put the spring and weight back in place.

Pros: Smooth shift. Not having to install rear brake or shifting components is nice.

Cons: Out of the box the spring tension on the shifting weight is too light, so shifting occurs at a very low pedal cadence.

Would Buy Again: Yes
Would Recommend: Yes

Reviewed on: January 18, 2013
Reviewed by: Aaron H.

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Excellent hub, very smooth shifting, and not bad looking at all!

Pros: Grest, smooth shifting, easy to modulate coaster brake. Can be changed from 120mm to 130mm rear spacing.

Cons: Very noisy, when ridden through compacted gravel roads it rattles a lot

Would Buy Again: Yes
Would Recommend: Yes

Reviewed on: December 10, 2012
Reviewed by: Jorge I. Fernandez

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Good Hub for a Commuter Bike

I use this hub on my steel commuter bike with 700c wheels. I had Universal Cycles build the hub into a Sun CR18 rim, and have been happy with the build. I am using the rim brake version of the hub. Shifting for me is consistent at 11.5mph. I use mine with a 38t front chainring and a 22t cog. This gives me a low gear of 46 gear inches and a high gear of 65 gear inches. Works great for sprinting around town in traffic! The hub has noticeably less drag than the Shimano Nexus 3 hub it replaced. It has a couple of minor negatives, but they are not deal breakers for me. When you coast while in high gear, the hub drops back into low gear. If you start pedaling again while above the shift point, the hub immediately re-engages high gear. You can feel this happen in the pedals, but I got used to it quickly. Also, when coasting over bumpy surfaces, I can hear a small rattle from the hub. The rattle is not there when pedaling over bumps.

Pros: Low Drag, Consistent Shifting, Easy to use in traffic

Cons: Hub drops to low gear when coasting in high gear, Small rattles can be heard when coasting over bumpy surfaces

Would Buy Again: Yes
Would Recommend: Yes

Reviewed on: July 18, 2012
Reviewed by: Scooby214

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