Can you elaborate a bit on this? I don't find my bib shorts (Castelli Free Aero Race, I think) to be more comfortable than my non-bib shorts (Assos and Pearl Izumi) and I certainly have not experienced any shifting of padding on any of them.
@cantunamunch mentioned the primary problems with regular shorts.
I'm a skinny Tinkertoy set with long legs. Few, if any, shorts were ever overly comfortable. I'd need to secure the waist fairly tight to keep them from migrating down and thus moving the padding away from my sit bones. The padding in bike shorts is supposed to stay put to act as a "blister rub zone" and prevent chafing and saddle sores. The fact that bibs have shoulder straps to keep them in place from above
without causing constriction around the waist is simply sublime. No shorts match this level of comfort for me.
I'm appreciative of tall cut bibs, which eliminates a good many brands from consideration for me. Velocio fits me well but oof, their prices are too rich for my blood. Hincapie fits me well but they're devilishly hard to find these days other than factory direct, and they're still pricey. The Black Bibs may not have the "sexiest" padding but the pad works well, they offer a tall cut in the Plus and Ultimate levels, and their build quality is quite lovely.
Note that I go on rides ranging from less than an hour to upward of 6 or 7 hours, so having a pad that sits well and doesn't shift is
super important.
The basic rule with bike comfort is to address the three contact points with the bike as well as possible:
- Butt (padding setup and saddle)
- Feet (socks, shoes, insoles/orthotics, pedals, crank length)
- Hands (gloves, bars, bar tape/grips)
Regarding saddles: I prefer flat, thin, and narrow setups. My road bikes have either an Ergon SR or a Fizik Antares R3, my gravel bike has a Brooks Cambium C15. The latter has a bit more give which is nice on rougher surfaces. All three play well with my various bib shorts in use. Anything with a pad that doesn't hit right has been retired.
And those bib shorts where the lycra has become a bit threadbare? Those are my liner shorts for times when I need to wear more "normal" clothing at the end of the ride and can't simply change clothes.