Originally Posted by
FBinNY
To the OP.
Why are you arguing against the answers you're being offered?
Occam's razor implies that the simplest answer is best.
An eccentric chainring - round but turning off center - explains exactly what you described in the OP. Moreover, it's extremely common, not some out of left field construct.
Like they teach medical students, "if you hear hoofbeats, think horses, not zebras".
If I was arguing against answers offered (and I'm not sure I was) it would only be because it didn't fit with what I observed with my own two eyes.
Part of the confusion is terminology. I am learning the bmx terms on the fly here, so it may take some time to sort that out so we are all talking about the same thing.
Also, a chainring mounted directly to the spindle can't be adjusted by "loosening mounting bolts" as was suggested. I may have initially ignored some replies if they were not actionable to fix the problem.
Finally, it is just a matter of my free time to spend on this forum. Between work & family, sometimes I am in a rush to test out the answers that jive most with my initial suspicions.
And, as it turns out, I got some good advice that confirms the bent (or non-concenttic) spindle theory.
But I appreciate all the responses, even ones that turn out not to be consistent with my specific issue.
There is no substitute for hands on experience when diagnosing a problem, so I understand that every possible explanation for my problem can't all be correct.
However, I am happy to learn about all the other possibilities that I haven't yet considered (whether they are all right or wrong is irrelevant).