8" Rotor, Single-Crown Fork = "Asking for trouble"?

(Pete Cresswell) said:

That assertion appeared in alt.mountain-bike today.

It's making me a little paranoid (8" Hope on a 'zocci x-fly
100 and an 8" Avid on a 'zocci Pro ETA)

Anybody care to comment.

Ask your fork manufacturer; some are refusing to warrant
their forks suitable for discs bigger than 160mm, others are
certifying above that
e.g. some Magura forks. If you really need the big disc,
chances are you also need a bigger fork.

Kinky Cowboy*

*Batteries not included May contain traces of nuts Your
milage may vary

(Pete Cresswell) said:

That assertion appeared in alt.mountain-bike today.

It's making me a little paranoid (8" Hope on a 'zocci x-fly
100 and an 8" Avid on a 'zocci Pro ETA)

Anybody care to comment.

tinyurl.comywfqsOpen ↗

Chris B. said:

(Pete Cresswell) said:

That assertion appeared in alt.mountain-bike today.

It's making me a little paranoid (8" Hope on a 'zocci x-
fly 100 and an 8" Avid on a 'zocci Pro ETA)

Anybody care to comment.

tinyurl.comywfqsOpen ↗

which, although the geometry seems a little bizarre to me,
makes the valid point that the loading on the calliper mount
can be somewhat larger with a bigger disk due to the
increased distance from pad to mount, which was apparently
the reason behind the recall of some Specialized bikes a few
months ago. I don't believe there were any actual failures
prior to that recall, but it was not in the warranty
specifications of the fork and we all know that what is
documented and verifiable is more important than what
actually happens in real life.

In any case, it doesn't seem directly related to the comment
in the original post (which I looked up on on a.m-b) that an
8" disk on a single crown fork will "literally rip it apart"
which sounds more like the typical uninformed guesswork of
the rad dude who hucks gnarly drop-offs in his baggy shorts
and [censored]-pot helmet.

lat3r d00d2,

James

RE/

Quoted message said:

tinyurl.comywfqsOpen ↗

Reading that discussion, it sounds like the mounting posts
are the point of failure. My Avid mechs have posts, but the
Hopes don't.

In both cases, however (intuitively...) it looks like when
the calipers are grabbing the disk, they want to rotate
forwards around the bottom mounting screw.

Since the bottom mounting screw is in the same place for
both 160 and 185 brakes and the rotation seems to simply
compress what's up there on the upper mounting screw...I
still can't see how the increased disc diameter can cause
a problem.

In fact, (at the risk of confusing the discussion) it would
seem that the further away the pads grab, the less is the
infamous "ejection" force....

OTOH, I'm more than a little paranoid about stuff like
this....I'd hate to have "Darwin Award Winner" be my last
thought as I endo-ed into that rock garden.
--
PeteCresswell