I've ridden literally thousands of kilometers with a 15kg topcase with speeds far exceeding the stated 130km/h. I've also known others that did so. Last month we finished a 3500 km trip around the Alps where a friend's CBR 600 F4i carried a Givi V47 that weighed around 20kg (case + contents) attached via this: https://www.givi.it/my-motorcycle/pr...optionals/252f
. No issues whatsoever, wasn't his first trip either.
I've seen overloaded luggage racks bending or breaking only on old, small bikes. Once on a Honda CB 500 and once on a Suzuki GS 500 (that one actually broke through a subframe mount, due to rust). In both cases, you could plainly see, by the construction of the rack, that it was not up for the job. The rails were too flimsy, it stuck out too much to the back, creating a large lever arm, the entire bike was shimmying when loaded...
On any bike where the rack looked
right, it also took heavy loads just fine, yet the producer's load and speed limits were the same for all motorcycles. Lowest common denominator? That's my guess.
Givi or SW-Motech probably can't be bothered to test their designs until the breaking point. There's way too many bikes and racks to cover. Instead, they likely have a standardized "pass/fail" test with like a 5kg load (or even no test at all, just an engineer signing off that it should be fine
) so all their warnings labels use that.
I can vouch for the OEM luggage rack on the Versys, it's as low-profile as it gets, very sturdy, doesn't stick out too much. It's surprising how well the bike handles with heavy load.