Pitted steering tube on a new bike

kambuh

My partner bought a new cyclocross bike a month ago. It hasn't been used much. There were some size adjustments done in store prior to purchase .
Yesterday my partner complained that the bike made some slight grinding noises. I couldn't hear them but discovered that the headset was loose. I tightened it but then could hear really awful grinding noise while turning the bar. I pulled the fork out and discovered one of the lower bearing balls had come off the ring and had been grinding against the steering tube. There was only half of the ball left. There was a lot of metal dust and, what's the worst, there is an ugly pit on the steering tube . It's not very deep - about 2 mm.
The bearing is slightly bent which made a a few balls fall out as soon as I pulled the fork out.
I know that the bike will need a new lower bearing but will most likely need a new fork too.
We are going to take the bike to the shop but I'm wondering how the shop is going to deal with this repair.
Does anyone have an idea what could cause this situation? As I said the shop mechanic had adjusted the headset just before we bought it. Could it be that he didn't put it all together properly and bent the bearing?

Thanks

ugo.santalucia

Sounds like it was badly fitted

balthazar

Bear in mind that the steerer tube (particularly the bottom end) is one of the most heavily stressed parts of a bike frame. You didn't say whether it is carbon or ali alloy, but I wouldn't be happy with a 2mm deep groove there either way.

kambuh

Fork: Double-Butted Cr-Mo Unicrown w/ double eyelets & lowrider bosses
This is the bike:
http://www.genesisbikes.co.uk/bikes/adv ... du-glandon

BillyMansell

It's unusual for a ball bearing to disintegrate and it would be hard to tell if it broke whilst caged or as a result of becoming loose. The bearing cage may have been damaged from first fitting but it would be hard to tell as the subsequent damage by the broken bearing will have knackered things anyway.

If the pitting is on the steering tube rather than the bearing surfaces then hopefully it's just a bearing change that's required but if you're concerned about the integrity of the steerer then you may be looking at new forks as well.

mattv

2mm is very deep. The steerer May only be 3mm thick tubing. Don't ride it, get it back to the shop asap. If the forks snap, that's usually a hospital and dentistry job.

mikenetic

kambuh wrote:

My partner bought a new cyclocross bike a month ago. It hasn't been used much. There were some size adjustments done in store prior to purchase .
Yesterday my partner complained that the bike made some slight grinding noises. I couldn't hear them but discovered that the headset was loose. I tightened it but then could hear really awful grinding noise while turning the bar. I pulled the fork out and discovered one of the lower bearing balls had come off the ring and had been grinding against the steering tube. There was only half of the ball left. There was a lot of metal dust and, what's the worst, there is an ugly pit on the steering tube . It's not very deep - about 2 mm.
The bearing is slightly bent which made a a few balls fall out as soon as I pulled the fork out.
I know that the bike will need a new lower bearing but will most likely need a new fork too.
We are going to take the bike to the shop but I'm wondering how the shop is going to deal with this repair.
Does anyone have an idea what could cause this situation? As I said the shop mechanic had adjusted the headset just before we bought it. Could it be that he didn't put it all together properly and bent the bearing?

Thanks

Is the pit on the tube itself, or the crown race? The crown race is the part of the headset that sits on the fork. If it's the race then that can be easily removed.

kambuh

Sadly it's the tube.

crankycrank

Just take it to the shop you bought it from before doing anything else. They may cheerfully agree to sort it for you under warranty.

Matthewfalle

Shop job - be really nice and polite, don't lose your temper: this usually ends in things being solved nicely.