# A Season with the SRAM iMotion 3



## BudMelman (Sep 9, 2012)

I took it out for a quick trail ride this morning and it works pretty good. 
It is laced to a WTB speed disc 29er rim, on a Misfit Psycles Dissent frame, Avid BB7 brakes and Ardent 2.4 & 2.25 tires front and rear respectively.
Fork is a Manitou Drake.

My plan is to run this all year in a real MTB trail environment.
I'll post back any issues or trouble I may run into.


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## lukeNZ (Dec 13, 2012)

any reason you choose the sram over the Nexus 3 spd disc hub?


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## BudMelman (Sep 9, 2012)

The SRAM shift cable disconnects easily, and its all inside the chainstay. Maybe a bit of brand loyalty, too. I have an Automatix hub, and SRAM bar end shifters on other bikes and it works really well.

After 2 rides I noticed play in the wheel and these axle nuts were out of adjustment, too loose. Nothing a couple of wrenches can't fix.


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## BudMelman (Sep 9, 2012)

Well the wheel loosened up again, so time to investigate. The small dia. wheel bearing on the disc side shredded its cage.










The internals still look good and shifting was good, but it doesn't like to shift under load. However, shifting while stopped or coasting seems like an advantage over a derailleur set up, if I can get used to it.


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## buddhak (Jan 26, 2006)

Subscribed...


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## BudMelman (Sep 9, 2012)

I'd still like to know why that bearing failed...
Anyway, was riding the trails a couple weeks ago and heard a 'crack', like when you shift a derailuer under load and it shifts with a crack through the wheel and frame. I'm sure we are all familiar with that sound, when starting a climb in the wrong gear.
But, I wasn't shifting, I was 'Just Riding Along'.
The hub worked fine for the rest of the ride, so I didn't think much of it. When I tore it down later, here is what I found,









Good pawl









Broken pawl

I'm having trouble finding parts for this hub. So I robbed a pawl from my Automatix hub, they are the same.
I also got a 2nd i-motion 3 to build a spare wheel, ' cause there's some racing coming up.


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## rifraf (Dec 22, 2012)

Love my Sram Dualdrive. I imagine its pretty similar to your hub except with a cassette on the outside as well. Mines never given me any issue. I find with hub gears easing up on the pedals for gear changes helps a ton, so I dont change under load no matter what the manufacturer suggests in the glossy brochure.


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## BudMelman (Sep 9, 2012)

It may shift under light load, like urban street cruising for which it was designed. But for MTBing, it's best to get in the right gear just before you need it.

There are only 2 pawls on that side of the hub, and maybe 4 engagement points in the hub shell, so there is a bit of free pedal rotation before engagement. I may have spun the cranks around and broke the pawl while it was trying to engage.

The hub internals have stayed pretty clean, despite the hub is not sealed very well at all.
The 3 gears have covered everything on the trails so far. It's a nice simple change from the 3 x 9 I was running a couple of years ago.


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## BudMelman (Sep 9, 2012)

Rode the 24hr of Summer Solstice at Albion Hills June 22 & 23.
Part of an 8 person relay team, I got 3 laps in.

The 1st lap I had to stop 3 times to reposition the axle/shift arm. The axle cannot be allowed to rotate. If it does, the shift arm turns up towards the chain, stretching the shift cable, putting the hub into 2nd or 3rd, and you can't downshift. If it rotates further, the shift cable pops off and you're stuck in 1st, spinning and no more shifting. The axle nuts have to be kept really tight.
Here, my shift arm, keyed to the axle's flats, is getting a bit chewed up compared to the new one.









New,









The hub's innards are still clean. But the cog, held on with a spring clip, is getting really sloppy.

Here I noticed the pawls are wearing on that outside tooth again. Thats the one that broke off earlier.










My Sram 8 speed chain has stretched alot as well. I had to move the rear wheel to tension the chain before my last lap, as it fell off on my 2nd, night lap.
I'm not sure if this hub will last the season...


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## BudMelman (Sep 9, 2012)

*Stick a Fork in it, she's done.*

Shortly after my last post, while climbing a short, but steep little trail bit, the hub went crack.
It wouldn't shift anymore, stuck in low, and if I pedalled really light, I could get some engagement and drive, and made it home. I could hear crunching going on inside.

Here's what I found when I slid the hub shell off.









The e-clip and washer were pushed onto the threaded part of the axle.
Taking that off, I pulled some gears out.










The small bits in the center are whats left of some pins or pawls that may be whats needed to engage or shift gears.

For what it was designed for, city streets, its a great hub. But with the disc brake ability, I just couldn't resist throwing it on my MTB.

I now have my white industries hubs back on that frame, and right away I could feel easier pedalling, especially compared to 3rd/High in the i-motion.

One thing this hub did help me with, was to bridge the gap. I went from 3 x 9 to 1 x 9 to 3 speed and now singlspeed and having fun.


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## ultraspontane (May 26, 2011)

Wow, this hub seems very unreliable. Why would you stick with it?


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## john_dalhart (Nov 6, 2009)

I ridden an iMotion3 since 2009. It's been a great little hub for me. Differences: 1) mine was on a folding bike with 16" wheels I used for bimodal commuting 2) Mine was built in Germany.

SRAM has moved the production of all their IGHs to Taiwan. You'd like to think that it wouldn't make a difference with modern factories and big companies, but broken pawls and a shattered bering cage (not the first one I've heard of, either) from an outfit that been building IGHs since 1904? Something is going on.

The iMotion3 is an elegantly simple hub that's easy to work on - but for naught, since SRAM doesn't support their IGHs with spare parts.

SRAM recently announced a big new push to return to being a major player in the IGH world. Not like this they won't.


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## BudMelman (Sep 9, 2012)

Some clarification;

This hub is designed for city street riding on a city-type bike. I put it on my mtb 29er to purposely torture it and see how long it would last.

I can't fault Sram for that. So please don't send Sram Team Six to my house in the middle of the night.

This bike now has White Industries ENO and MI6 disc hubs on it. Those hubs cost waay more than the i-motion 3 and have only 1 gear.

Again, this was an experiment with the i-motion 3 to deliberately see how long it would last.

I'll dismantle the hub as much as I can & take some pics. Then those of you who know IGH workings ( 'cause I don't ) may get a better idea of what went wrong inside.

I have another, new i-motion 3, and I wouldn't hesitate at all to build it into another bike, just not an off-road bike.


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## surreal (Jan 25, 2008)

I think this was an awesome experiment. Thanks, Bud, for trying this and posting your experiences. TBH, I thought it'd have blown up faster than it did.

I've been toying with trying an SA S2 on a trailbike, but really, i know it'll die early, so why waste it? I think I gotta pony up the cash for an n360 and get on with it.


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## lukeNZ (Dec 13, 2012)

Bud, 

Be interesting if you tried your experiment again but with a Nexus SG3D-55 hub. From my experience and from the limited stuff I can find on this site and others, this hub can actually survive a degree of mtb heat. (don't think it'd enjoy dh/dj much)


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## r1Gel (Jan 14, 2004)

This is an awesome thread. Very informative.
Thanks for posting.


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## dischucker (Apr 9, 2008)

I just thought I'd add a tidbit of info to this thread WRT to the coaster brake version of this hub. My daughter's bike came with the coaster version but it also had both front and rear calliper/V brakes, so I was wanting to remove/deactivate the coaster - which she never uses and makes it harder to ride out of the saddle/coast as she would sometimes activate the brake accidentally.

So I looked into removing the coaster brake element. The only thing I found was this YouTube clip about removing the coaster brake from the 7 speed version.

So I took the hub apart and although it was similar, the internals were not the same as the 7 speed version. The main difference was the brake "pads" (outer parts) were slotted in the hub housing and remained there when you removed the main axle assembly. This initially confused me as I didn't think to look in the hub housing so couldn't work out where they were. But once identified, they were easily pulled out.

Removing them did not seem to affect the functioning of the hub or bearings and I did not remove the rollers as suggested in the video, as they were all held together with the split ring thingey with the rest of internal parts of the hub (this assembly appears to be a single replaceable part if you look at the SRAM technical docs).

So I hope that helps anyone else trying to do this. I welcome any suggestions/warnings, as I'm no expert in this area.


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## Chris McCarthy (Dec 21, 2013)

I was ready to buy this hub for a 29er build so I'm glad I found this post. it sounds like mountain biking is just to hard on this hub and not its intended use. I'm back to being on the fence between a 3 speed hub and singles speed but at least I can rule out the i-3. Thanks for the informative posts.


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## car bone (Apr 15, 2011)

there is also schlumpfdrive and hammerschmidt, its 2 gears.


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## BudMelman (Sep 9, 2012)

At it again. A SRAM Automatix, 32H, 135mm spacing, and disc brake. Will follow up after I build it up and ride it awhile.


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