Re: Failed Zipp T2 Front Track hub pics

[jim beam]

Gemma_k wrote:
> For your holiday amusement:
>
> http://img6.picsplace.to/img.php?file=img6/24/arghZipp.JPG
> http://img4.picsplace.to/img.php?file=img4/27/failedzipp.JPG

looks like another victim of "tension as high as the rim can bear" to
me. were they ever trued or "helped" by a wrench, or were these
straight from factory?

 

[Gemma_k]

"jim beam" <[email protected]> wrote in message
news:[email protected]...
>> http://img6.picsplace.to/img.php?file=img6/24/arghZipp.JPG
>> http://img4.picsplace.to/img.php?file=img4/27/failedzipp.JPG
>
> looks like another victim of "tension as high as the rim can bear" to me.
> were they ever trued or "helped" by a wrench, or were these straight from
> factory?

Straight from the factory like that. Never touched them with a spoke wrench
(never had to, that is, until I had to remove 24 spokes from the rim to get
the hub out :-/
>

 

[[email protected]]

jim beam wrote:
> Gemma_k wrote:
> > For your holiday amusement:
> >
> > http://img6.picsplace.to/img.php?file=img6/24/arghZipp.JPG
> > http://img4.picsplace.to/img.php?file=img4/27/failedzipp.JPG
>
> looks like another victim of "tension as high as the rim can bear" to
> me. were they ever trued or "helped" by a wrench, or were these
> straight from factory?

Funny thing is, according to what I've read on this ng, zipp rims can
bear less than most, which would imply an even weaker than normal hub.
I would tend to think that this failure was not caused by excessively
high spoke tension, but by poor quality hubs.

 

[Gemma_k]

<[email protected]> wrote in message
news:[email protected]...
>
> jim beam wrote:
>> Gemma_k wrote:
>> > For your holiday amusement:
>> >
>> > http://img6.picsplace.to/img.php?file=img6/24/arghZipp.JPG
>> > http://img4.picsplace.to/img.php?file=img4/27/failedzipp.JPG
>>
>> looks like another victim of "tension as high as the rim can bear" to
>> me. were they ever trued or "helped" by a wrench, or were these
>> straight from factory?
>
> Funny thing is, according to what I've read on this ng, zipp rims can
> bear less than most, which would imply an even weaker than normal hub.
> I would tend to think that this failure was not caused by excessively
> high spoke tension, but by poor quality hubs.

I don't know about that re: the rims - the track rim looks pretty beefy,
weighs in at 460g by my scales. The spokes were quite highly tensioned, no
sign of any of the spoke holes in the rims failing (touch wood!). The spoke
head holes in the hub perhaps are too deep, so the thickness of the flange
is really 'wasted' or overengineered, making a stress raiser across the
spoke holes?

My Suntour Supurbes are still holding up---supurbely - best hubs EVER

Gemma

 

[rooman]

<[email protected]> wrote in message
news:[email protected]...
>
> jim beam wrote:
>> Gemma_k wrote:
>> > For your holiday amusement:
>> >
>> > http://img6.picsplace.to/img.php?file=img6/24/arghZipp.JPG
>> > http://img4.picsplace.to/img.php?file=img4/27/failedzipp.JPG
>>
>> looks like another victim of "tension as high as the rim can bear" to
>> me. were they ever trued or "helped" by a wrench, or were these
>> straight from factory?
>
> Funny thing is, according to what I've read on this ng, zipp rims can
> bear less than most, which would imply an even weaker than normal hub.
> I would tend to think that this failure was not caused by excessively
> high spoke tension, but by poor quality hubs.

I don't know about that re: the rims - the track rim looks pretty beefy,
weighs in at 460g by my scales. The spokes were quite highly tensioned, no
sign of any of the spoke holes in the rims failing (touch wood!). The spoke
head holes in the hub perhaps are too deep, so the thickness of the flange
is really 'wasted' or overengineered, making a stress raiser across the
spoke holes?

My Suntour Supurbes are still holding up---supurbely - best hubs EVER

Gemma

wow...must be some tension ... Zipp claim these T2's as "the strongest hub flanges ever tested in their laboratory"

(from Zipp...The new hubs utilizes a the brand new Z310.9 super-alloy designed by Zipp in conjunction with Alcoa specifically for hubshell use and combines with ZippÌs ground-breaking Spoke Hole Impact Forming Technology (SHIFT) to produce the strongest hub flanges ever tested in our laboratory"
: http://preview.tinyurl.com/yjx4az
may have been a fracture coupled with over spec spoke tension ...just enough straws...