Originally Posted by
KraneXL
Higher center-of-gravity. Something that you notice immediately especially when you already sit tall in the saddle. The straps can also bind and interfere with your breathing. The last thing you need is to have the weight shift when you lean into a turn.
You also mentioned comfort, and while not functional will certainly shorten your duration and/or make your ride a whole lot less enjoyable. I've had times when the weight was so bad I literally had to stop and walk.
I find bike handling to be much better with a back pack than with loaded panniers. I can ride a lot more aggressively and have better control of my bike. I am using small backpacks which are about 20-25 liters.
You mention that your pack was so heavy that you had to stop, were you carrying an anvil or something ??:....Being a little uncomfortable is good , it makes you stronger and builds mental toughness.