dvt wrote:
> jim beam wrote:
>> i disagree. no manufacturer that cares about their reputation enough
>> to put their name on their product is going to risk damage to sales by
>> shipping something they know to be a problem. otherwise why bother
>> with the considerable expense of vacuum degassed steels as well?
>
> Do spoke manufacturers use vacuum degassed steel?
>
>>>> perhaps, but we'd then have to show that residual stress was a
>>>> factor and that material quality was not.
>
>>> I think this is where we disagree. The first part of your sentence
>>> makes sense to me, but the second part doesn't. Why does one have to
>>> be exclusive of the other? Why couldn't some failures be caused by a
>>> *combination* of material quality and residual stress?
>
>> they could, but why spend your time fixing the hubcap if the fan
>> belt's broken?
>
> The hubcap and fan belt are not related.
that's my point - one will stop the car working, the other, although it
has a function in other aspects of vehicle use, doesn't. "residual
stress", it must be assumed, is a constant since spokes are made the
same way today as they were in the old days. it's only the introduction
of more fatigue resistant material that has impacted failure rates. the
practice of spoke squeezing, bedding in, "stress relief", whatever you
call it, has been around since the advent of the wire-spoked wheel.
> Residual stress and material
> quality may work together to cause the failure under discussion. I have
> seen no proof that they are related, and I have seen no proof that they
> are *not* related.
as above, if the only variable is material but all other production
factors are constant, and we get different results, we /have/ to
conclude that whatever effect residual stress may be having, it's as
important as the hubcap.
>
>>>> seriously, if spoke squeezing was able to eliminate fatigue
>>>> regardless, don't you think manufacturers would just do that and use
>>>> cheaper materials and cheaper processing rather than what they do now?
>>>
>>> Perhaps if they were able to assume no residual stresses in a spoke
>>> in a built wheel, they *could* go to cheaper materials and processing.
>>
>> doesn't work that way in practice. real world usage is that material
>> quality /does/ affect failure rate. spoke squeezing has no quantified
>> efficacy that i've ever seen.
>
> Aye, there we agree. No one has published a study that shows the
> efficacy of spoke squeezing, and no one has published a study regarding
> material quality in spoke elbows. As you said in another thread long
> ago, we don't know what we don't know.
>
