Originally Posted by
caterham
-you added photo attachments of the cinelli crown after my post- i don't understand why- please explain
-the links that i attempted to open from within your referenced thread all resulted in 404 not found's
I have no *problem with that* per se but i asked because even after perusing the entire reference thread i still have no idea what your point is. as i read the referenced thread, the discussion centered around the potential of a stress raiser to be introduced by the use of an insufficiently prepared cinelli-style investment cast crown of the type using internal lugs. a number of opinions were voiced, some in support and some refuting and/or further qualifying the topic.
our op states that there are no signs of failure to the fork crown and no breakage or separation of the blades- just that one blade is notably bent backwards and with a crumple/deformation zone just below the crown on the *rear* of the blade as one might expect of any fork crown design, whether internal or externally lugged.
Listen, I'm just trying to be more helpful to the OP than most would entertain. I feel badly for the guy (and the accident victim) and I'm giving him some quick research to consider in his search for an answer. You, OTOH, are offering what you know to be true ,but without relevant support, and are now trying to turn the attention of the readers from the pertinient to the personal. I'm not a problem, the problem, the cause or the solution. I'm just offering what I can to help.
In answer to this:
>>our op states that there are no signs of failure to the fork crown and no breakage or separation of the blades- just that one blade is notably bent backwards and with a crumple/deformation zone just below the crown on the *rear* of the blade as one might expect of any fork crown design<<<
I say look above this post by two or three and you'll see that I've answered it already. I'll reword it to make it a tad easier for you to understand:
The fork of a bike is a sub-system assembly that is co-dependent on all of its various parts (tire,tube,rim,rimtape,spoke heads, spokes, hub flange, axle, QR, dropouts, blades, crown, braze, steerer, headset, stem bars, etc.) to form a reliable, functional front end system. A failure, or a load borne deformation anywhere along the chain of sub-assemblies will cause an excessive load to be placed on the next load bearing link in the chain. Evidence of which part of the chain failed first will
probably be seen in that area
if you know what to look for and if the next part of the chain
isn't overtly substantial
, in which case said evidence will end up later along the chain.
My initial opinion was that the hub flange, QR or the axle had broken. I said that because, if the wheel were to jam within the fork blades and cause one to be bent whilst the other were more/less intact, it would seem to me that load bearing was one sided, as caused by the wheel tilting to one side before being jammed to a stop within the fork assembly. A failure though, in the elastic strength of one of the fork blade could cause the same thing. Hence the reference to the Brandt threads.
If that explanation isn't enough for you, then someone more patient than I will have to help you through it.
Danny