Help: Axle broken twice in 1 month

[Paul Hunter]

Hi All

 

I have had the same issue twice now in less than a month.  The axle that is inside the rear hub which the skewer goes through has cracked in half.  As mentioned this has happened twice now.

 

Any ideas what could be causing this?

 

Thanks

Paul

[Hairy]

Hi Paul, which hub is that.

 

I just broke the axel on my superstar components Trizod rear hub.

[JXV]

That One up extender cog increases the force transmitted through the rear wheel quite significantly although this should act through the hub outer body and not the fixed axle on which it rolls.

 

The location of the failure is at the outer edge of the drive side wheel bearing. This is quite far inboard of the support at the dropouts so it is the most likely point of failure for a break caused by bending moment. I am thinking that a combination of factors is causing this such as modified cassette plus lightweight hub plus heavy rider plus hard impact.

 

Did both failures occur in the same part of the axle?

Was the extender present in both cases?

What type of hub?

Hard tail or full sus?

Rider weight?

Speed and severity of impacts?

Is there any jumping involved?

[Skylark]

And this is the reason I don't like through axles. I have seen it a few times now. I don't know the problem but you definitely need to contact the makers of the product.

 

That looks like a QR axle though?

But ja some hubs like the Hope Pro II, when setup and used with through axle are not the most robust, appears they need to machine the axle wall too thin to accept the thicker through axle and that makes it pretty weak.

[David Marshall]

Looking at the pic it seems as if something is grinding the axle before it breaks as there appears to be a lot of filings around.  In addition to the suggestions above check that the bearing is running smooth and that all the freehub spacers and bearings are in the right position and working.  Possibly use a steel axle with the extender cog?

[droo]

That's a Novatec by the looks of it, and the freehub bodies have been known to rub on the axle and wear through, particularly the steel bodies.

 

Their newer rear hub has a bearing on the back of the freehub body which addresses this issue.

 

Check that the bearings are properly seated and try again. If it breaks again I'd suggest a new hub.

[Paul Hunter]

Hey Guys

 

This is a QR axle.

 

Did both failures occur in the same part of the axle? Yes
Was the extender present in both cases? Yes
What type of hub? Novatec
Hard tail or full sus? HT
Rider weight? 77kg
Speed and severity of impacts? Not sure
Is there any jumping involved? No jumping

[JXV]

Hey Guys

 

This is a QR axle.

 

Did both failures occur in the same part of the axle? Yes

Was the extender present in both cases? Yes

What type of hub? Novatec

Hard tail or full sus? HT

Rider weight? 77kg

Speed and severity of impacts? Not sure

Is there any jumping involved? No jumping

You're not heavy and not jumping it but it is a HT so impact forces will be higher on rough stuff. Should not break that easy tho. Droo's post might have the answer. If it is wearing/rubbing then you should see evidence of this on the outside of the axle near the fracture point.

 

Only other cause I can suggest is incorrect assembly....both times.

 

Maybe consider a new hub. For a QR bike you can't go far wrong with good old Shimano XT rear hub. Steel axle, adjustable bearings, good spares availability, last for years if u put a bit of grease in now and then.