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  • Nexus Hub Gear Query
  • bugcab
    Free Member

    Bought a second hand commuter with Nexus 8 speed hub gear.

    Had terrible drag on freewheel so stripped it down de-greased and relubed following much web wisdom.

    Still enough friction to cause the pedals to turn on freewheel and not be able to pedal backwards for fear of chain coming off.

    Are all these the same or is mine just a bit knackered?

    Ta.

    bentudder
    Full Member

    Have you checked the chainline and chain tension?

    bugcab
    Free Member

    Not looked actually, will try check tomorrow but the problem seems to be from the hub. You can feel the friction on freewheel at the sprocket even with the wheel off.

    bencooper
    Free Member

    The foolproof repair technique for Nexus hubs is as follows:

    1. Remove rear wheel,
    2. Place in the nearest recycling bin.
    3. Fit an Alfine instead – or Rohloff if you can afford it.

    bugcab
    Free Member

    [quotebencooper – Member
    The foolproof repair technique for Nexus hubs is as follows:

    1. Remove rear wheel,
    2. Place in the nearest recycling bin.
    3. Fit an Alfine instead – or Rohloff if you can afford it.[/quote]

    Feared that may be the case, trouble being 24″ rims with Alfine dont come cheap!! Guess I will just have to pedal a bit harder and get a bit fitter.

    Andy-R
    Full Member

    What did you re-lube it with – ATF or grease? I’ve used both in Alfine hubs and I reckon the best I’ve used is Rocol Aerospec 100, which is a semi-fluid grease used in Q400 prop hubs, among other things.
    Less draggy than the original grease but doesn’t migrate past the seals like ATF can.
    Also check that the cones aren’t over tight – I set them so that with one end of the axle held in a vice there’s a gnat’s cock of play at the rim – once it’s in the frame you’ll lose that.

    philtricklebank
    Full Member

    The foolproof repair technique for Nexus hubs is as follows:

    1. Remove rear wheel,
    2. Place in the nearest recycling bin.
    3. Fit an Alfine instead – or Rohloff if you can afford it.

    Mostly this, except if you have the last nexus model revision (product code ending in 36, e.g. SG-8R36), as that one has identical internals and seals to the Alfine – I’ve run one for 8 years daily commuting all year round and all weathers without problems (so far).

    I’d give +1 to cones a bit tight, but if the freewheel is turning the pedals then chain tension may also be a touch too high. How does the wheel spin with the chain off? That should give the answer as to overtight cones or chain tension being the issue. These hubs don’t spin as freely as an ordinary SS or cassette rear hub, but they shouldn’t be unbearable either.

    philtricklebank
    Full Member

    Oh and it should be pointed out that a new 8r36 complete hub is only (!) £120 online, and you can just put the new internals into an existing hub shell from some of the old Nexus hubs – 30, 31 and 35 model numbers included, possibly others – it’ll say on the shell what you have. Saves you having to relace an Alfine into the 24″ wheel if things really are poked.

    bugcab
    Free Member

    Helpful stuff folks.

    I am fortunate enough to have the “red band” 36 model so still some hope it seems. Thankfully just the friction issue at the moment so not yet at the stage of new internals, just dont want to ruin the thing in my attempts to get a smoother freewheel.

    I re-lubed after a full de-grease by immersion in Gearbox oil followed by fairly liberal application of lithium grease on the bearings (not fully stripped down so cant get to the drive side cone bearing). Have to say the lithium grease did seem to add friction but I read somewhere (having no real knowledge or expertise myself) that oil bath alone insufficient.

    I have a pot of the insanely expensive Shimano Nexus specific dunk oil on order so may again de-grease and try with that or perhaps the aircraft grade stuff (probably still cheaper) that you have found to work. Guessing you did not add any other grease after your special gear Andy R?

    I did tighten the cones carefully but they were “just” tight opposed to leaving a tiny amount of play so will check that out. Will also have a look at chain tension but there certainly is drag on freewheel even disconnected.

    Thanks again for all help and advice.

    Andy-R
    Full Member

    bugcab – Member
    Helpful stuff folks.
    I have a pot of the insanely expensive Shimano Nexus specific dunk oil on order so may again de-grease and try with that or perhaps the aircraft grade stuff (probably still cheaper) that you have found to work. Guessing you did not add any other grease after your special gear Andy R?

    No, I just used the Aerospec 100 after flushing the internals with ATF and leaving them to drain.
    As far as the aircraft stuff being cheaper - here you go . Probably not much in it at £77 for 500 gms.

    I’ve got two Alfines and the older one is using the Rocol and is a lot smoother and nicer than the one that still has the original lube. Of course, it’s also done 3000 miles more, so is well run-in.

    bugcab
    Free Member

    Crikey, lube that is more expensive than the Shimano Blue Gloop.

    Cones backed off a little last night and massive improvement. Still friction on back pedal but isolated this as being between rear sprocket and dust cover on the hub, seems you cant do a lot about that, design issue.

    Thanks for offers of help and technical guidance.

    bentudder
    Full Member

    Good to hear it’s all sorted.

    As an aside, I’ve taken one of the coaster brake versions and stripped the brake and spacers from the non drive side to fit the hub into a 120mm spaced singlecross frame. Aside from being an affront against humanity, it’s worked very reliably on road and off for the last few years, and cost me peanuts.

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