Bicycle Mechanics - What causes the cones in a front hub to deteoriate?

I recently reported a loud metallic clicking noise in my front wheel....I got quite away from home. The front wheel started vibrating and got unbearable noisy... It got drastically worse all of a sudden. Glad a bike shop was nearby because I was over 20 miles away from home.
They changed out the cones.Said they were crushed. No further damage done to the hubs, races, axle. I caught the problem in the knick of time.
What could have caused these cones to deteroriate before their time..Me...Tighten skewer too tight. Grease. ?
First time I have ever had that problem...Hate to have that happen in mid tour way out in the desert. Bike must have well under 15,000 miles on it.

Could have been an overtightened skewer. The handle should leave just a light imprint on your hand when you close it. The cones could have been overtightened just a little too much when it was orginally assembled or last overhauled.

'Crushed' cones sounds improbable. Overtightened cones seems more likely. Dry cones, dirt entered cones, or too tight QR skewer seem like likely second choices. Riding in the desert might cause dryness or grit entering cones? When was the last time you overhauled / lubed the wheel bearings? Who did the work?

You think maybe the ball bearings have worn down? Have you lubed up the ball bearings enough?

Koffee

'Crushed' cones sounds improbable. Overtightened cones seems more likely. Dry cones, dirt entered cones, or too tight QR skewer seem like likely second choices. Riding in the desert might cause dryness or grit entering cones? When was the last time you overhauled / lubed the wheel bearings? Who did the work?

Think that has not been done, ever...Think they are sealed bearings...When they show signs of wear, they are just replaced. No?

I would expect the ball bearings to fail first if your cones were massively too tight..but the cones would probably be pitted also, and unusable....

I once had the greyhound bus co crush bearings in the wheels i was shipping by laying them down and loading something heavy on the end of the axle...I rode on it a while before it failed...the balls were crushed into pieces...

I'm not entirely sure how 'sealed bearings' are prone to fail?

I would expect the ball bearings to fail first if your cones were massively too tight..but the cones would probably be pitted also, and unusable....

I once had the greyhound bus co crush bearings in the wheels i was shipping by laying them down and loading something heavy on the end of the axle...I rode on it a while before it failed...the balls were crushed into pieces...

I'm not entirely sure how 'sealed bearings' are prone to fail?

Appreciate hearing of your experiences..Later in life I will have to start maintaining my own life..Commute/work schedule,I just want to ride and my free time and hopefully get the grass cut.
My mechanic never mentioned greasing hubs/bearing in its annual tune up. Don't think greasing any part of the hubs has ever been done to any of my bikes.. I can only recall hearing, should the bearings in the wheels make noise, change them out
..He charged me twenty bucks for materials..Did not mention changing out the bearings. Just cones. Have to ask him to check for sure.

Appreciate hearing of your experiences..Later in life I will have to start maintaining my own life..Commute/work schedule,I just want to ride and my free time and hopefully get the grass cut.
My mechanic never mentioned greasing hubs/bearing in its annual tune up. Don't think greasing any part of the hubs has ever been done to any of my bikes.. I can only recall hearing, should the bearings in the wheels make noise, change them out
..He charged me twenty bucks for materials..Did not mention changing out the bearings. Just cones. Have to ask him to check for sure.

If you truly have sealed bearings then you would not need to service them until they fail. However, sealed bearings do not have adjustable cones and would be replaced in their entirety when the do fail. If you mechanic replaced the cones, then you should have non-sealed bearing that do need periodic maintenance. If the bearings have never been serviced, then I would expect them to eventually fail, beginning with the cones.

I don't understand the 'crushed' description. Cones are solid and are very unlikely to be significantly deformed by any normal cycling forces. Usually, the bearing surface of the cone becomes pitted and rough with wear. Perhaps your cones were in very poor shape and the mechanic used the term 'crushed' simply to indicate that they were beyond gone.

If you truly have sealed bearings then you would not need to service them until they fail. However, sealed bearings do not have adjustable cones and would be replaced in their entirety when

Sealed bearings are usually loose bearings (or bearings in a retainer) with cups and cones. Sealed implies there is a barrier between the bearings and the outside world.

Cartridge bearings are the ones you are referring to. Bearings inside a race assembly. Typically "maintenance free / not user servicable", ride em till they fail, then replace.

The sealed confusion comes from sealed cartridge bearings. These are std industrial parts, used on bike wheels, but designed for high speed use. The seal is there to prevent grease being sucked out, not water and dirt getting in.
On a bike wheel, you can get cartridge and cone variety which are sealed for bike use.