# Sturmey-Archer S3X or SRAM i-Motion 3 for MTB?



## mwarner57 (Jul 27, 2006)

I realize it may a be a bit early to get feedback on the S3X for MTB use, but has anyone had a chance to try both of these hubs either on or off road? I would like to put a 3-speed hub on my 29er SS to make it bit more versatile (grocery runs, baby trailer, etc...). The reviews I have seen on the Nexus 3 have not been very good, so leaving that choice out for now. Thoughts?


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## mwarner57 (Jul 27, 2006)

Looks like I would be needing the SX-RK3, since I have disc brakes. I especially like the description on the SA website "• Extra wide hub will accomodate a big rear end". Which is one of the reasons I need an IG hub in the first place:sad:


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## john_dalhart (Nov 6, 2009)

Your request is confusing.

The unique Sturmey-Archer S3X is a fixed gear hub. It doesn't freewheel (coast).

The Sturmey-Archer SX-RK3 is an extra wide hub - it has a 170mm O.L.D. - for "low rider" style cruiser bikes.

To repurpose a normal disc-brake equipped SS 29er, the two choices in disc-compatable three-speed IGHs are the Shimano Nexus SG-3D55 and the SRAM iMotion-3 Disc.

Here's a thread with some info on those two hubs.

JD


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## mwarner57 (Jul 27, 2006)

It's my understanding that it is possible to install a freewheel on the S3X? No matter, there does not seem to be disc version currently, and my frame is disc-only  

You are correct on the SX-RK3. I didn't read the fine print on the Sturmey-Archer site for that hub.


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## mwarner57 (Jul 27, 2006)

Looks like my decision has been made for me :
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360230777448
Evidently, the seller has several more of these built up if anyone is interested. I should get mine sometime this week. Photos and impressions to follow.


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## mwarner57 (Jul 27, 2006)

I got the wheel the other day. It uses a Salsa Delgado Cross rim and 14 ga. spokes. First impressions are that it was nicely built, but HEAVY. The wheel weighed in at over 4lbs. with no tire or tube. 
I mounted it on my Zion SS bike, which was already 29 lbs, so not a very light combo. I had to get creative with the cable routing since this is a SS frame, but it wasn't rocket science. One thing I did have an issue with was that the hub uses tabbed washers to keep the axle from rotating. The tabs are meant to sit in the slot for the dropout, but since my frame has an eccentric BB, the dropouts are similar to a geared bike, and the tabs really had no place to go (more on this later). The axles are held on by some industrial-size acorn nuts, so you really need to carry a 15mm wrench with you if you need to change a flat.
I ran with the stock (21 tooth) rear cog, and a 30T up front. 2nd gear on the hub is 1:1, so the overall ratios are pretty low.
The first ride was about an hour-long fireroad ride pulling a baby trailer with my 35lb. son in the back. There were some steep hills on the ride, so I was putting some pretty serious torque on the hub. The hub was nice and quiet, and shifts were positive, although the hub refused to shift under load. Not a big issue, since I wouldn't normally do that on a derailleur-equipped bike anyway...
Second ride was at China Camp State Park in San Rafael. There is some nice singletrack there with moderate climbs and a few rocky sections. Having two more gears made it much more fun. I wasn't spinning my brains out on the flat sections or straining up the climbs. The gear jumps felt like a 2 or 3 gear change on a normal bike, so the gear changes were pretty infrequent. I generally used 3rd for the flats and 2nd for climbs. It was kind of an odd combination of a geared bike and SS. I had to stand for the short climbs because the gear jumps were just to large to downshift for them.
So far, so good. Next ride was at Tamarancho in Fairfax. It is rockier than China Camp with some steeper sections. I found myself using all 3 gears because of this, but still never felt the need for anything lower than what I had. I got to the "Dragon's Teeth" section, which is just a huge boulder, basically, and requires a few gymnastic moves and a short, hard pull to get up and over. I ended up torquing the wheel out of the dropouts, so I tightened the nuts are far as I could and tried again. Still pulled out. I ended up putting everything back together and riding back down the hill in defeat.
I think the dropout thing may be a showstopper. I am either going to have to weld on some standard SS dropouts or get another frame if I want to keep using this hub for MTB. It's too bad, because the hub itself, though a tad bit heavy, seems to be up to the task.


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## john_dalhart (Nov 6, 2009)

I'm not sure what to tell you.

The SRAM iMotion3 hub is _supposed_ to come with two 00 0391 021 000 Retaining Washers. These are serated face washers with NO tabs.

Your ebay seller states that the wheel you were sent does NOT come with the iM3 washers but instead with the 00 0991 01X 000 Retaining Washers for the iM9 hub. (The "X" is a digit code for specific dropout geometries. These are color coded, too.) These iM9 washers do have a tab on them. I do not know why your ebay seller does this.

I've not pulled my iM3 wheel out of vertical dropouts using the correct iM3 washers. YMMV.

BTW, I estimate an iM3 hub is less than 600g more than a run of the mill combination single speed hub and single speed freewheel. On a bike that was already 13,000+g that just doesn't seem like much weight penalty.

HTH,
JD


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## mwarner57 (Jul 27, 2006)

Thanks for info, John. It looks like there may be some serrated washers in my future. Regarding the weight, 600g was not a huge increase for my lead sled, but I made a note of it because it may be of concern for someone else wanting to install this on their 21 lb. SS.


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## exile29 (Jul 15, 2010)

are you still using this hub? i am interested, but i killed an older model hub on the first ride with 32/19 on a 29er. maybe just bad shifter adjustment . . . ?

also, the ebay listing says it is a 135mm disc hub, but i asked the seller and he said it wasn't. which is it? i know the rim is for rim brakes.


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## mwarner57 (Jul 27, 2006)

I am parting out that particular bike, but have been riding for a few months. Drilled some holes in the dropouts and modified the washer tabs to fit in those holes, which prevented the wheel from popping out. It seemed to work well once set up.  The hub is disc and the rim works with rim brakes, so you can use with either. Pretty sure the spacing is 135mm, since it fit in my frame with no issues. I can sell you the wheel for $80 + shipping if you want it, but you will need to come up with some new anti-turn washers.


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## exile29 (Jul 15, 2010)

did you ride on trails much? i liked mine on the trail fine until it blew up


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## mwarner57 (Jul 27, 2006)

I took it off-road a few times, but nothing epic. Was your hub the newer model?


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## exile29 (Jul 15, 2010)

i bought it a couple of years ago, so maybe not. it wasn't disk compatible.


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## exile29 (Jul 15, 2010)

PM sent


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