I would soften this statement a little bit. I understand you have had a very frustrating experience, violette, and that's really unfortunate. Frankly I think your bike shop was remiss in not asking you to think seriously about whether you would be well served to make such a big change in gearing, it sounds like you ended up with a very nice bike, but gearing is a big factor in buying a new bike and it's one that shops really ought to bring up, especially with newish riders.
However, I'm no racer, just an ordinary recreational rider, and I just switched from a bike with 52/42/30 & 12/23 to a bike with 53/39 and 12/25. I live in Vermont, so it's not as hilly as where some of the women here live, but it's definitely not flat either. My biggest problem so far is really not that the low gears are not low enough, it's that 39 is different from 42, and on flat to somewhat rolling terrain, I find myself wanting to ride in 39/12 a whole lot. Even with the Ultegra half-shift though, I can't ride in 39/12 because I get significant derailleur rub. The shift from 39/13 up to a higher gear is still pretty awkward for me. I actually checked out my gear spread on a gear-inch calculator, and it makes sense that I"m having issues, because 39/12 falls right between 53/16 and 53/17 -- in the first place, the chain angle (on my bike, at least) at 53/17 is starting to look like cross chaining, so I tend not to like the looks of riding in that combination, but more than that, it's a big shift -- up one in front and down 4 in back, and I'm still having trouble doing it smoothly, so I neither spin up to 140 for 30 seconds nor lose momentum because I've suddenly drastically increased my gear.
So the issue i'm having with my new standard double is not that the gearing is way too hard, but that I'm finding the transition from the low end of the medium gearing to the high end of the medium gearing (and vice versa) a bit awkward. I'm sure I will improve at this with practice though, it's just a matter of getting used to something different...
I know this doesn't address violette's original question, I just felt compelled to defend standard gearing as an option which may be at least possibly legitimate for some "regular", recreational riders.
I was a little surprised that violette was advised to check out the gear calculator earlier in the thread. Not that gear calculators aren't useful -- it's just that gear inches don't mean much abstractly. I think you have to have a fair amount of experience with your own gears and know with a reasonable degree of specificity what combinations you use and what works for you on given terrain before gear inches can provide any sort of useful comparison. Just my .02.
Sorry, guess I'm the grouch this morning... hope you'll let it slide this time

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