internal gear hubs well sealed?

Discussion in 'Cycling Equipment' started by garage sale GT, Sep 15, 2007.

  1. garage sale GT

    garage sale GT New Member

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    Does anyone have any experience commuting in the rain with a newer internal gear hub such as a nexus or a sturmey? (I have both.)

    I have not torn mine apart to see if they are sealed. I am concerned the water-borne grit will migrate into the bearings and gears and eventually destroy the hub.

    Perhaps the lack of sealing is the reason they say not to off-road these hubs, except for certain exceptions.
     
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  2. garage sale GT

    garage sale GT New Member

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    I know the reaction will be "What do you think those hubs are made for?"

    However, I had a Shimano from the 1980's which had metal dust caps and no seals of any kind. A year of occasional commuting was too much for it. It was a comfort component designed for maintenance free use in good weather.

    Perhaps that's why these hubs are greased and not oiled nowadays; the grease may be intended to help keep grit from migrating.
     
  3. rodar y rodar

    rodar y rodar New Member

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    I have a Nexus 8-speed that certainly seems well built, but I haven`t had it apart either, nor have I had it in any wet weather. There`s supposedly an external boot available for the shifting aparatus that I wouldn`t mind getting ahold of if I ever locate one. For what it`s worth, a few folks on mtbr.com report excelent weather resistance with their Rohlhoff Speedhubs (for that kind of price, it dang well better be good).
     
  4. garage sale GT

    garage sale GT New Member

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    Well, I took my Nexus 3 speed apart and it did have a rubber seal at one end, but the other end was just double shielded. I bet one of the functions of the special Nexus grease is to keep dirt from circulating.

    The Sturmey-Archer 8 which I have does not need service yet but the freewheel bearings are merely shielded, not sealed. You can actually see them between a gap where the freewheel meets the hub if you remove the shift cable holder.

    I do not know about the other bearings in the hub.

    The Sturmey-Archer X-FD front drum is equipped with sealed cartridge bearings, albeit small ones.
     
  5. rodar y rodar

    rodar y rodar New Member

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    Did you have any trouble getting your hub apart? All the "guts" come out together?

    As far as the grease, I dunno- I guess it probably helps to keep out what doesn`t belong, but the little bit that seeps out of mine from time to time looks fairly thin. Just guessing, I`d say it`s mostly just for lubrication purposes.
     
  6. threaded

    threaded New Member

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    IMHO only the Rohloff hub is actually 'man enough' for the job of regular commuting. Your average regular cyclist can output more torque than any of the other current internal gear hubs can withstand.

    The Nexus etc. are absoultely not designed for the purpose you're attempting to use it for. They are only designed for people who pedal at way below sweat threshold, when it's not too wet.
     
  7. garage sale GT

    garage sale GT New Member

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    Actually, the nexus looks pretty new inside including the gears and bearing races. The axle is straight.

    I may not be able to sustain a race-winning pace for the duration of a race, but am able to put out some power. Sometimes I dance up a 10% grade by my house. I also ride over broken pavement, trails, grassy shoulders, etc. And the clay soil in Illinois is hard enough to drive a car over without leaving a mark, when it's dry, so riding in the grass is a bumpy ride. It may have about 500 miles of serious use (I relubed it with thinner stuff in the hope of cutting down resistance, not because it needed it). I weigh 200 pounds or so.

    I don't jump the thing and slow down/unweight over big bumps but it's not some little piece of crap. I'd seal it myself but there's no way to get a felt washer between the sprocket and hub.

    The hub came apart very easily. I have not reassembled the hub yet because I just got the proper Nexus grease a few days ago. 1/2 synthetic grease/1/2 synthetic oil allowed the coaster brake pads to gall even though they were saturated with the stuff. The noise coming from the brake was one reason for the overhaul.

    The hurdles to reassembly will be: 1. keeping it grit-free, and 2. keeping loose ball bearings in place; I don't want to try to find new caged balls.

    I hope I get it back together OK. but it looked pretty simple. There are schematics on Shimano.com.

    It may break if I tried to downhill it but it's good enough for commuting.
     
  8. rodar y rodar

    rodar y rodar New Member

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    Threaded- sorry you don`t like Nexus or SA. My advise would be for you to not buy one.

    GT- I`m confused. You put a lighter lube in your hub or you were waiting for Nexus lube? Somebody else had a light lube in it and it leaked into the coaster brake? I would think that bumps, jumps, potholes etc would be much harder on the rims than the hubs, but I guess it takes a toll everywhere. Glad your hub looked good. Mine is pretty new too- I`d guess about 300 miles and I`m thinking it would probably be a good idea to open it up, flush it out and regrease it to get any initial break-in chips and gunk out of it. Out of curiosity, what kind of bike do you have it on? Mine is on a rigid mtb frame (Univega) that I use for commuting, Sunday rides with the old lady and general errands around the neighborhood.
     
  9. garage sale GT

    garage sale GT New Member

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    Well, first I put light lube in it, then it started to make noise and I had second thoughts, then I took it apart to make sure it wasn't destroyed, then I ordered the Nexus grease from Harris Cyclery.

    Coaster brakes are designed to work in grease. The grease is supposed to be there. If you repack yours, make sure you don't leave the pads dry.

    Road shock can ruin hubs as well as rims. The old freewheel style hubs, for example (tenspeed hubs, still used in more or less the same form on 21sp mtbs and road bikes) used to break or bend axles right and left.

    My Nexus is on a Next cruiser from wal-mart. The bike is stock except for a longer seatpost, fenders, and a straighter mtb bar.

    I bought the Sturmey as part of a Cadillac AV-8 comfort bike, then decided to put it on a Nashbar steel MTB frame. I shelved the project for a while and it is incomplete.
     
  10. artemidorus

    artemidorus New Member

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    You want to strip it down after ~500km?? I would like to think that you ought to be able to multiply that number by at least 10 before the first disassembly. I thought that the point of the things was low maintenance.
     
  11. garage sale GT

    garage sale GT New Member

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    From the looks of the low-end coaster brake 3-speed I have, I do not believe the hubs need to be taken apart after break-in. I regret my impulsive decision to try to oil my hub and the consequent need to strip it down.

    The job does not look particularly complicated but there's always a risk of grit contamination or of incorrect bearing preload. (how do you tell if there's a very slight preload when you have to turn a geartrain with the axle?)

    The gear teeth look like powder metal components. There are no hobbing marks on them; their surfaces are smooth.
     
  12. garage sale GT

    garage sale GT New Member

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    Well, for anyone who's still interested, I finally got around to it. The sprocket end of the hub has a seal and a tight fitting dust cap.

    The coaster brake end, however, is different. There is a sheet metal cup over the end of the hub. There are two grooves in the hub (covered by the end of the cup) which in my opinion ought to have O-rings but one had a metal snap ring (not retaining anything) and one was empty. Also, there is a grease port in the end of the sheet metal cup which can be rotated under the brake's reaction arm to close it but it is neither sealed nor tight fitting.

    The LH hub bearings are just under there, just outside of the brake.

    It was a dry summer and fall around here, so I do not know if the hub would have kept out the gritty water. It did keep dust out. I am going to put an O-ring in that groove and try to seal the grease port with a few winds of teflon tape or something.

    All in all the hub came apart and went together very easy although you need a 22mm cone wrench to adjust it. Whoever heard of a 22mm cone wrench?
     
  13. rodar y rodar

    rodar y rodar New Member

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    That`s good to hear, GT. I don`t know about the cone wrench, but it`s no big deal- at least they`re cheap.

    Artemidorus, if you`re still watching this thread, I was thinking about cleaning it out because it just seems like the thing to do after the initial running of any moving parts. But I`m going to follow the advice above and leave it be.
     
  14. JoakimT

    JoakimT New Member

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    My girlfriend rode a bike with Nexus 7 about 5-15 km daily for almost five years. Year around and we are talking about central Sweden, that is loads of rain in spring and fall, and snow in the winter. At the time she actually did not ralise bikes need attention, so she never leave it to a bike shop for service or anything - just kept on rolling.

    Both my girlfriend and I now changed to Shimano Alfine, that is hydralic discbrakes and with two gearwheels it adds up to 16 gears. Sheaper than Rohloff!
     
  15. rodar y rodar

    rodar y rodar New Member

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    Two gear wheels on the Alfines? I didn`t know that. A lot of people in the US are waiting anxiously for Alfine to be available because they will accept disc brakes (but I still like my rim brakes). So far, I think they are only in Europe. Glad you and your girl like your hubs- I like mine too and want to build a Nexus wheel for my wife next year.
     
  16. JoakimT

    JoakimT New Member

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    You canĀ“t buy alfine in Sweden either (just in some Cannondales that you have to custom order). Most "cyklopats" in Sweden order bikes and parts from Germany. Check out these stores:

    Parts & bikes: Roseversand (English version available)
    Parts: Action Sports (English version available)
    Bikes: Stevens bikes(English version available)
     
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