|How can I tell if my DA hubs have a sealed bearing or need..||surf|
Feb 20, 2002 5:05 PM
|How can I tell if my DA hubs have a sealed bearing or need lubing. Obviously I have never packed bicycle bearings (or I wouldn't be asking). The hubs are older - 7 speed freewheel- and spin perfectly but since the bike was purchased used I thought it could use some good preventative maintenance. Also any tips for re-packing and lubes to use. |
A side note, when I got the rear wheel re-dished, the mechanic said if the bearing aren't loose and spin good don't worry about them. That sounded kinda strange so I just thought I would see what you guys think
Feb 20, 2002 6:54 PM
Feb 21, 2002 3:04 AM
|Bit of a strange question, seeing as if you have DA hubs I'm assuming that you're probably an experienced rider who's done most of his/her own wrenching...
If one of the more experienced wrenches on the board can back me up if I'm wrong, please add amendments.
First off: there are two types of bearing systems: cartridge or sealed bearings, and traditional cup-and-cone "loose" bearings. Sealed/cartridge bearings basically have the bearings packed into a small cartridge that you can replace when the bearings wear out. Cartridge bearings are often referred to as sealed bearings because they're packaged into what seems like a sealed or enclosed unit, but in reality, they're not really sealed as in water-proof sealed - water and fine grit can still work its way into the cartridge, albeit quite slowly in some cases, and once in, may actually be a little harder to get out compared to cup-and-cone systems. "Loose" bearings are the more traditional way to house bearings - the bearings sit in a recessed part of the hub (the "cup" part) and are prevented from coming out by a sort of lid (the "cone" part) which is held on in turn by a locknut.
That's why I'm a little confused when you're asking if your hubs have a sealed bearing or need lubing - sealed bearings can't really be lubed (well, they can, but that would take a LOT of work). It's like asking if someone's car is turbo-charged or needs gas. Not the same things.
To check if your hubs are cup-and-cone or cartridge: check the sides. If you have a locknut on the outside, it's probably cup-and-cone. If you can see a flat cartridge exterior under the dust cap, possibly with some numbers embossed on it, the answer is self-explanatory.
To check if they need lubing: spin 'em. Take off your wheel, spin it, then hold the wheel in both hands by the axel (not the skewers) while the wheel spins. If your hubs need lubing, the wheel will feel gritty and won't spin smoothly. If your wheel feels smooth, but aren't spinning for a while and you have a cup-and-cone systems, loosen your cones by loosening the locknuts with a cone wrench. If your wheel keeps spinning effortlessly for a long time, the bearings are most probably fine. If there's excessive play when you spin your wheel, tighten your cones.
Preventative maintenance: just ride and avoid wet weather. If you ride in the rain, spin your wheels once you're in a dry spot or after your bike has dried off a bit after your ride. Spinning your wheels will work out some (if not all) of the water that might have worked its way into the bearing systems. Also, check your wheels every once in a while to see if the bearings are still good.
Re-packing and lubing: This is starting to turn into an essay, sheesh. Cartridges, just knock 'em out and replace 'em with a new cartridge. Get your LBS to take care of this if you don't know how, otherwise, I'd recommend going to an industrial bearing shop, finding bearings from there, and installing those than getting new bearing units from your LBS - you'll usually get better quality bearings from the industrial shop. Cup-and-cone: loosen the nuts, take off the cone, pry out the bearings if you can, clean out the cup, loosely pack the cup with grease, replace the bearings, clean off the excess grease if necessary, replace the cone and locknut, and ride. Or just pay your LBS to do it for you. Or, buy a maintenance book.
At this point, I've said more than my fill, and I've spent more than 15 minutes trying to type this out. Anyone else have any comments?