Sorry if you do not understand.

I was asked how much of my 50 second time improvement was due to the tire size.

The conditions during that day were much worse than my prior PB. I have a 50 second time differential and an increase in power output on a day with worse wind, worse humidity (dry day), lower temperatures, a slight headwind from which to tease out how much of the 50 seconds was due to tire width, how much was properly tucking my camelback hose, and how much of it was the additional power.

If you can give me a tutorial on that? I do not think it is possible. At least, I would have had no way to calculate that time differential even if I was interested in doing so back then.

If a rider has a CdA of 0.250 riding at 25 mph and another has a CdA of 0.150 riding at 30 mph and both lower their CdA by 0.01, the time savings will be dramatically different for each over any distance and not really meaningful in such a forum.

Edit: I suspect the M5 Two Spoke Sail effect on some portions of the course had a massive effect. I PM'd Hambini, I am sure he can divine it for me. I cannot. It is also important to realize estimation of CdA on a pipeline is not the same as being able to say how much of a time improvement one will get on an open road because there are so many variable on the open road compared to a wind tunnel or a windless, carless testing street. The road surface alone is different from those two locations. So, even though a 23 mm tire is measurably better than a 25 mm tire, I cannot see how one can take a time on a course and compare it to a previous time and then say how much of that time improvement is due to one thing like a tire that fits flush to the rim. I have no idea how to do that.