Set up a Nexus 3 speed coaster brake.

Discussion in 'HOW TO' started by horsefarmer, Dec 16, 2019.

  1. horsefarmer

    horsefarmer

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    Got this Nexus 3 speed with Alex Xrims 303 front and rear aluminum wheels. Looks like this right now (no mounting hardware, cog or shift mechanism.).
    nexus 3 speed wheel.jpg nexus 3 speed wheel 2.jpg
    This was part of my late brothers last build off bike that he never completed.

    I have never worked with a Nexus 3. Usually I get my parts by dismantling complete bikes so small parts come along with. Wondering if everyone buys these wheel assemblies like this and then buys the parts to complete installation separate or were the rest of the parts shipped with the wheels in a box somewhere?
    nexus 3 speed shifter.jpg nexus 3 speed.jpg
    Also, not is there no cog, there is no snap ring either. :(
     
  2. Wildcat

    Wildcat

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    It depends where it was bought, but usually you get the cog and dust cover. I'd dig around in all the parts to see if they were put in a safe place. You'll need to get the stuff shown above to set it up. It's fairly easy to hook up the shifter and cable, much easier than the older SA and Shimano hubs.
     
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  3. horsefarmer

    horsefarmer

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    Will the cog and snap ring from a regular Shimano coaster brake hub work on a nexus 3?

    The bike frame got painted and the front wheel mounted - kinda in the advanced mock up stage with the rear wheel sitting near the bike stand.
    [​IMG]
    I will go back and dig some more. The above pic is from the unfinished build thread. Looks like a couple of interesting plastic totes under the desk that have been moved since he died.
     
    Last edited: Dec 17, 2019
  4. SpikeFC

    SpikeFC

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    Sometimes it happens that wheels are sold without a cog, dust cover, ring, or any mounting parts.

    Things that you need, are:

    *Cog - Shimano recommends using cogs raging from 18T up to 22T, but I'm running a 16T and it works, but the gear ratio is a killer if you want to go uphill.

    *Shimano Nexus 3spd Components - it's a set with everything that you need - cog dust cover, cog ring, one retaining washer, push rod & two nuts

    *Shifter (with cable & outer casing) & Shifting mechanism - comes in most cases as a set, but with these 3 speed hubs, you can actually use any kind of 3 speed shifter, or even an non-indexed shifter (I'm using a racing, frame mounted shifter, on witch I only put a dot for the second gear position, since 1st gear is "all out" and 3rd gear is "all in")
     
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  5. Phil Fink

    Phil Fink

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    Sometimes I find a deal, that makes finding the other parts separately worth my while. Shimano has a website with lots of literature and illustrated parts breakdown diagrams, and installation instructions.
    • Like others have said the hub needs a "trim kit" - (make sure it is not for the other models though). I usually get a separate larger cog/sprocket anyway. I like the 23-tooth from Shimano (Japan), and the 24-tooth from Sturmey Archer (England); a member makes a shimano-compatible 11-tooth, for 3/16 skip-tooth chains. The ring clips come in rounded or squared spring wire, either will work.
    • The rod may also be separate, be sure to get the right length, which depends on the axle length, but most 3C41 hubs have the same axle.
    • Not sure if Nexus uses an odd 3/8-24tpi thread axle/nut (not 26?).
    • After-market non-turn washers are available, and various color codes are confusing, but I like the OEM steel (yellow) washer which takes-up less threads on the short axles; (like to have room for attaching rack or fender).
    • The shifter, cable, and "cow bell" parts can also come in a kit, and sometimes I have opted for the integral shifter with brake lever; the handlebar mounted shifter comes in black or silver, (and in different styles).
    Old Shimano LH shifter-brake-lever.jpg
    As far as adjustments go, it may be a bit of trial and error, tightening or loosening the cable at the bottom end, as necessary - again detailed instructions are online (Shimano), and on other threads.
    A word of caution regarding older or vintage parts - sometimes the interfaces might not work. Sometimes, I figure if there are more than one seller who is selling the same part, that it may be more likely to fit something else that I recently purchased.
    https://www.ebay.com/itm/Shimano-Ne...d-Washer-3-Speed-Cruiser-Bicycle/382424482815

    https://www.ebay.com/itm/Shimano-Nexus-3-Speed-Grip-Shift-Cable-Kit-New/264570085944

    https://www.ebay.com/itm/BICYCLE-IN...S-SL-3S35E-BEACH-CRUISER-CHOPPER/391232454189
     
    Last edited: Dec 18, 2019
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  6. Starnger

    Starnger

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    Singlespeed shimano cog and snap ring would work, but dust cover probably won't, and you need it for proper cog placing, otherwise it would sit loose.
    I indeed often have to get those parts separately, or even customize them to fit my builds. But that comes from a guy who never bought one from the store in a box, i get mine from resellers or from disassembling bikes usually, so no surprise they often lack parts.

    True so about the cogs and the shifters. You can even run 14t cog on this hub, but it is indeed hard to pedal and also eats away the teeth really fast.
    Nexus hubs are also possible to operate with SA/SRAM/SACHS shifters, though sometimes catching a second gear might not be as smooth as with original shifters. Older Shimano 333 shifters work as well. Centrix do not, since they have too much different pulling. I mean technically you can use it, but it would destroy your shifter pretty soon.
     
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  7. jamesdart

    jamesdart

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    Sturmey archer has a nice thumb shifter for the nexus 3
     
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  8. horsefarmer

    horsefarmer

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    I did find these...
    IMG_1723.JPG
    loose parts to mount hub.
    IMG_1725.JPG
    19t, 21t and 23t cogs,
    IMG_1728.JPG
    20t Bendix cog, Misc parts for 4 to 8 speed Nexus hub, short cable housing.
     
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  9. us56456712

    us56456712

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    Regular snap ring works as does a cog from a China Shimano knock off single speed coaster.. Bendix is a little different but can be made to work by carefully filing the cog notches. Perhaps you have an old China coaster wheel with a the trim ring, snap ring and cog. Try that. I have a 23 tooth cog on my Nexux with a 30 tooth chainring. It lasted about 3 years of single track before it started to shift poorly. The yellow tab may not work as there are several different kinds available depending on the drops. The yellow one worked on my old cruiser.
     
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