Einstellen des Lagerspiels bei Innenlagern: Unterschied zwischen den Versionen

* 22 einzelne 1/4" [[Lagerkugel]]n, die sich auf die beiden [[Käfig]]e aufteilen (in seletnen Fällen findet man auch weniger Kugeln)

Removing and reinstalling bottom-bracket cups is covered in a companion article, which includes information on tools, including an improvised right bottom-bracket up remover. (But don't remove the right bottom-bracket cup unless you need to replace it, as that article explains ).

When you take a bottom bracket apart to repack it, there are a couple of other things that you can do to keep your bike happ.y One is to spray LPS or some similar treatment up into the tubes and chain stays to retard rust. [2012 update: the favored treatment is Jl P. Weigle Frame Saver, available at better bike shops -- John Allen] Another is to make sure that the bearings are protected from contamination by one of the special plastic sleeves made for the purpose. I used to use liners cut from tin cans or plastic jugs for this, but the accordion-type sleeves made for the purpose give a much superior seal, and they are quite inexpensive.

Do not think that you don't need a bottom bracket sleeve just because you have a closed seatpost! Although open seatposts on bikes without mudguards are the leading cause of dirty bottom brackets, even the cleanest, most carefully made bike is likely to have leftover brazing flux, paint chips, or other debris inside its frame tubes. All of this will eventually wind up in your bottom bracket, thanks to the modern miracle of universal gravitation!

Don't reuse bearing balls. New bearing balls are inexpensive, and for another, it's hard to check the old ones over for wear and damage. It is very important that all of the balls in a race be from the same production lot so that they will all be the same size. Good quality bearing balls from a given lot will usually be within two or three millionths of an inch of each other in size, but if you mix lots the difference can easily be 25 or 30 millionths. If there is this much difference in size, the smaller ones might just as well be missing for all the good they will do!

Most newer bicycles come with "caged" bearing balls-the balls are held in a metal or plastic retainer. This makes it easier to install the balls, but usually at a cost in performance. A standard three-piece type bottom bracket takes 11 loose 1/4-inch balls per side. Most retainers hold fewer balls, so each ball and its contact points with the cup and cone are more heavily stressed. This causes higher friction and more rapid wear.

Keep the spindle supported from below until the adjustable cup is screwed well in, because if you release the spindle while the cup is very loose, the balls may fall out of position.

Whenever you adjust a set of cone-and- cup bearings, you want to wind up with a perfect (or nearly perfect) adjustment. In the case of bottom brackets, the hardware has some special quirks that can make this goal seem unattainable. Here's how you can conquer those quirks.

If, on the other hand, the lockring of the bicycle you are working on can be tightened without tending to turn the adjustable cup, you must first adjust the cup so that the bearings are too tight, then tighten the lockring. The lockring will pull the adjustable cup out just a bit, and if you have judged correctly, the bearing will then be correctly adjusted.

Either way, it is a process of trial and error. With practice, you can learn to get the adjustment right after just a couple of tries, but this requires that you "educate" your hands. If you have not done this job many times, you should expect to have to keep loosening the lock ring and readjusting the bearings five or ten times before you have it right.

The bottom bracket is much more heavily stressed than the wheel bearings, and you will not usually be able to make it feel nearly as perfect as you can with a good wheel bearing. The adjustment should be made with the cranks off the spindle.

First, adjust the bearing to be clearly too loose. Revolve the spindle slowly with your fingertips-do not roll your finger tips around the spindle, but revolve it by turning your wrist. Your fingers should stay in constant, light contact with the spindle.

Bearing play is checked by trying to rock the end of the spindle up and down. Ideally, there should be no play at all, but in almost all cases, if you eliminate the play completely, the bearing will bind. If in doubt, it is better to have the bearing just a bit too loose than too tight [But see Jobst Brandt's opinion, which is opposite -- John Allen]. In my experience, only Campagnolo bottom brackets can be adjusted for no play and still turn as freely as they should.

There is some disagreement on which parts are "axles" and which parts are "spindles." Either the wheels have axles and the bottom bracket has a spindle, or vice versa. In an old issue of Bicycling, someone (I think Dick Swann) stated that the distinction is based on whether the part turns or not; hence, the hubs have axles, which do not turn, but the bottom bracket has a spindle, which does. The dictionaries I have checked seem to bear this out, but I won't get mad at you it you prefer to speak of hub spindles and bottom bracket axles. Just don't use that horrible redundancy "crankarm" around me --e ither "crank" or "arm" is correct by itself, and I can't stand unnecessary redundancies that serve no useful purpose!  

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