Loud Metal Ginding Noise From the Hub



Recently my full suspension Giant Reign 2 occasionally gives this very
lound metal grinding noise from the rear hub.

This only appears when I am going down hills, and it doesn't matter if
I am pulling the brakes. It would come out for a few seconds then go
away.

Does this sound like a bearing problem?

But other than the noise, I don't see any shaking or wobbling of the
rear wheel and it spins smoothly.

If this is a bearing problem, can my LBS replace just the bearings or
they'd have to replace the entire wheel? The hub looks completely
sealed to me. BTW, it is an Alexrim wheel with disk brake. The bike is
one year old. I go off-road and downhills about twice a week with very
small jumps on terrains that is not really rough. If it is indeed a
bearing issue, it kind of surprises me.

I will take my bike to the shop tomorrow, but I just like to get an
idea on what the deal is before that so I know if the mechanic is
telling me the truth.

Thanks in advacne for sharing your knowledge.
 
[email protected] wrote:
> Recently my full suspension Giant Reign 2 occasionally gives this very
> lound metal grinding noise from the rear hub.
>
> This only appears when I am going down hills, and it doesn't matter if
> I am pulling the brakes. It would come out for a few seconds then go
> away.
>
> Does this sound like a bearing problem?
>
> But other than the noise, I don't see any shaking or wobbling of the
> rear wheel and it spins smoothly.
>
> If this is a bearing problem, can my LBS replace just the bearings or
> they'd have to replace the entire wheel? The hub looks completely
> sealed to me. BTW, it is an Alexrim wheel with disk brake. The bike is
> one year old. I go off-road and downhills about twice a week with very
> small jumps on terrains that is not really rough. If it is indeed a
> bearing issue, it kind of surprises me.
>
> I will take my bike to the shop tomorrow, but I just like to get an
> idea on what the deal is before that so I know if the mechanic is
> telling me the truth.
>
> Thanks in advacne for sharing your knowledge.



Sounds like your freehub body is toasted, or just about toasted. Ya
gotta love shitmano.

JD
 
[email protected] wrote:
> Recently my full suspension Giant Reign 2 occasionally gives this very
> lound metal grinding noise from the rear hub.
>
> This only appears when I am going down hills, and it doesn't matter if
> I am pulling the brakes. It would come out for a few seconds then go
> away.
>
> Does this sound like a bearing problem?
>
> But other than the noise, I don't see any shaking or wobbling of the
> rear wheel and it spins smoothly.
>
> If this is a bearing problem, can my LBS replace just the bearings or
> they'd have to replace the entire wheel? The hub looks completely
> sealed to me. BTW, it is an Alexrim wheel with disk brake. The bike is
> one year old. I go off-road and downhills about twice a week with very
> small jumps on terrains that is not really rough. If it is indeed a
> bearing issue, it kind of surprises me.
>
> I will take my bike to the shop tomorrow, but I just like to get an
> idea on what the deal is before that so I know if the mechanic is
> telling me the truth.
>
> Thanks in advacne for sharing your knowledge.


Not so familiar with Alex stuff, but you can get a much better idea of
what's going on by removing the wheel from the bike and spinning the
axle and the freehub with your hand.

On the side opposite the cogs, spin the axle with your finger. (BTW:
the axle isn't the quick release. It's the tube that the quick release
passes through.) If there's significant, notchy resistance while
turning the axle, the bearings are likely contaminated or getting
crunched. This can be a fix ranging from cheap to total hub
replacement:
- if they're loose ball, the bearings have to be removed, the cones and
cups checked for wear (or 'pitting', which basically means you're
shelling out for a new hub), repacked, and the cones adjusted.
- if they're sealed, pop out the old ones and either try and jam some
lube in there or replace.

If spinning the freehub (basically, that means slowly turning the cogs)
sounds like a peppermill, there's your culprit. Also, if you turn the
cogs backwards (so that they click rather than catch) and the wheel
comes along with it, it's likely your freehub. Best bet is to get some
light oil in there and hope that the grit or whatever works its way
out. Be wary, though. The pawls of worn freehubs can lock up (giving
you a cool fixed-gear when you least expected it) or, worse, fail to
engage, which is sorta like snapping a chain while you're climbing. Why
worse? Failure of your pawls to engage will likely make your bawls
engage with your top tube.

/s