...large discrepancies...circumference in my bike computer...tyre pressure...calibration....amended...distances recorded...my calculation...spreadsheet...absolutely negligible.
wkc,
I admire your rigorous approach to tracking down the errors. But I am lazier (by a lot!) than you are.
I have a Cateye Astrale wired bike computer that is C&V-worthy, and I track my rides on a phone using Ride/w/GPS. When they did not agree, I lowered/raised the circumference number in the Cateye until they
did agree within a tenth! Took a few rides, but not many, to get them synced.
Which one was correct to begin with? I don't know, but I think the GPS. (There are no cul-de-sacs on my routes.) Why must they agree?
Because I like them to agree!
So now, they're either both right, or both wrong, but they agree.
All best to you in Oz.