Cup and cone bearingreplacement parts

For QR hubs, a good target amount of play off the bike is such that the play can be felt on the bike with the QR 50% closed but not 100%. Some people use tools either commercially available (the Stein axle vise) or improvised to adjust the hub while under QR compression. That is technically better but slower.

Some people talk themselves into the idea that a bias towards loose is okay in some circumstances, but it is not. One of these scenarios is when prior damage (pitting, brinelling) or a bent axle is creating a situation where you have a rough spot unless you make the whole thing loose. The correct answer is still as loose as possible without play. Neither is perfect in this situation, but if you give it play, the overall condition will get worse faster.

Cup and cone bearingsizes

Too loose is can also be hard on bearings and bearing surfaces but in a different way. And, at least it will be a better ride for a little while.

Cup and conehub diagram

A bike is commonly full of cup and cone bearings: pedals, hubs, bottom bracket, headset etc... The component change but the logic still the same the bearing is in between an axle, a pair of cones and a locknut. Sometimes, when you overhaul some bearings it's almost impossible to achieve the perfect tightness of the cones and locknut, if you retry you'll get a bit loose, sometimes a litte tight, never the in between perfection. It has happened to me only ones/twice that I was really satisfied about the tightness, so I was asking to myself: better to leave a bit loose or a bit tight?

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Cup and cone bearingreplacement

As loose as possible without play. Bearings are supposed to have some amount of preload, which is a fancy name for being a bit tight as opposed to being loose. There should never be play once adjusted and on the bike.

For some bikes perfection is not possible. Like when working on a brand new or used box store bicycle or when working on a beat up bike and you don't have the parts you need right now....