It's not about the handling being bad. Especially with lighter loads. It's just... less good, for lack of a better term, than midsize front loads on many bikes. A probably even better way to describe it is that it's just *different*, not better or worse. For me, once I start loading some six packs, or anything else in the 5+ pound range on rear racks, I just really start noticing the weight balance. Bikes are already biased towards the rear, throwing a bunch of cargo even more off to the rear, especially behind the axle, makes the front end really twitchy and light feeling but without actually handling fast.

Meanwhile throwing that weight over the front, especially if you can get it low and in line with the axle, or more central also has an effect. And it's an even more immediate effect, you feel the steering resisting just that bit more from the start. However once at speed I feel much more stable, planted, and that the handling is more like it *should* be. I found that once I was used to the initial resistance, the ride was much more pleasant. But that's not to say I feel rear loads are wrong or bad, just slightly less preferable in the low-mid weight range.

Just to get even more nitpicky, though, I feel like if I had the choice between really loading a bunch of weight on only one rack, I'd rather overload the rear than the front... haha