Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 (Tek) 9/28/84 based on 9/17/84; site tekecs.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!genrad!decvax!tektronix!orca!tekecs!barrys From: barrys@tekecs.UUCP (Barry Steel) Newsgroups: net.bicycle Subject: Re: "Sealed bearings" ? Message-ID: <5578@tekecs.UUCP> Date: Wed, 7-Aug-85 11:32:51 EDT Article-I.D.: tekecs.5578 Posted: Wed Aug 7 11:32:51 1985 Date-Received: Sun, 11-Aug-85 06:29:50 EDT References: <8300005@ada-uts.UUCP> Reply-To: barrys@tekecs.UUCP (Barry Steel) Organization: Tektronix, Wilsonville OR Lines: 35 >Anybody knows what 'sealed bearings' mean? How exactly are they sealed? Sealed bearings are tapered roller bearings (like the kind you have on the wheels of your car). They require (almost) no adjustment and dirt can not get into the bearing, as each one is a sealed unit. They do, however require special tools to service. One the other hand, "sealed hubs" are more common and cheaper. They consist of a "maze" that is supposed to keep out the dirt. They have the standard, ball and cone bearing set up. These should do a better job of keeping out dirt than regular ball and cone bearings, which simply have a plastic shield to keep out the dirt. | | <---- dirt must go through "maze" | | |-----------| | | | |o o| | ========<=========>======== axle | |o o| | | | |-----------| | | | | Sealed Hub I have bikes with each type of bearing. The good quality ball and cone bearings seem to roll as well as the sealed bearings. In rainy Portland, the sealed bearings seem to be impervious to the wet, while the regular bearings require more maintenance in the wet weather (no data yet on the sealed hubs). My preference, given free choice would be the sealed bearings. I believe these will be standard on all *good* bikes in the future (like permanentantly sealed bearings on cars are now). Hope this helps, barry steel