My question is mostly about allowed precision error on a new BMX frame,
and from a repair shop point of view - what amount of rear triangle
displacement is required to tell that frame is untrue and needs fixing?
Some background story:
Last year I've ordered a custom frame from SBC, it was around october i think.
I was really happy to see it arrive a bit earlier than they have estimated,
just before my birthday. It looked truly great, and while looking it around,
i've looked at rear triangle alignment as a joke (as if it could be wrong on a new frame,
especially SBC one, you know). I can't really forward changes in my face expression
as recognition of assymetry there was becoming more clear with every second.
But, remembering where i ordered the frame, i was more likely to believe
my eyes are wrong, so i did pretty much every validation possible, triple-checking
everything, with things you can find around the house, and all methods kept telling me frame
is untrue.
There were some other minor issues too, which are outside of question topic.
Nothing to do, i had to mail SBC, giving a detailed description of a problem
i've seeing. After few mails (first they suggested to build frame and see how it works,
despite obvious flaws) i was asked to send frame back.
So i've sent frame back, asking to let me know how it is. After some month of silence,
i write again to check how it goes, and get a reply they have received it long ago
and there was nothing wrong with the frame.
What?..
Then I've got one of pics i made before to describe an issue, and created an animation out of it,
so that issue is obvious, and sent another mail with some flames.
After that it turned out their employee actually fixed frame before reporting
everything is ok with it. I'm not really sure how you can fix such a problem, tbh.
Well, ok, no problem.
By some wild chance frame arrived back after checking on friday 13th..
And guess what, not much has changed!
This order, i believe, is not less legendary than SBC itself.
I've mailed SBC again but didn't get another reply in two weeks, so i think they
don't want to talk to me anymore about this.
I don't have any problems with SBC whatsoever, they sure can work how they want,
it's more of my problem that i like or don't like their work. This story might
be valuable for people considering to order something there, though. But keep in mind that
my experience with SBC sure may vary from other's, and this is perhaps a somehow outstanding issue.
Maybe other Standard owners have seen similar issue?
Also, as i see it, no allowed precision errors are settled on during custom
frame build arrangement, so objections are not tecnically valid.
So i'm asking this question here just for myself, to know if
my overview of the frame i received is reasonable/valid. It could
be that most vendors do frames like this and it's totally normal.
My current frame, which is used for a while, and other frame i have
do not show such an issue when tested using same technique.
What are general allowed precision errors on geometry?
For example:
Headtube 74.5 degrees (+/- 0.05 degrees)
Rear dropouts: (+/- 1mm)
Is displacement shown on animation enough to consider (new/used) frame untrue?
Animation i made before sending frame back
After receiving frame back
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