I bought an Oxford M30R tank bag earlier in the year. When I tried it at the shop it seemed great, and they always do when you’re sat on the bike in a car park, but in practise it’s not so good and I’ll be getting rid of it.
It’s a great bag size-wise, and with all the pockets and the hole for my USB cable to go through it’s really practical, but because it’s magnetic and because of plastic on much of the tank - staying on isn’t that good.
I find that the magnets tend to loose adhesion sometimes if I go over 80 and I end up with my tank bag hovering in the vortex, which can be a bit of a surprise. Thankfully the front strap stops me from loosing it altogether while I try to slow down and get the damn thing re-magnetised to the tank. I even used araldite to stick some washers underneath the aluminium ‘eyebrows’ but that didn’t make any difference so it’s going.
It’s a shame because I like everything else about the bag. My next one will be a quick connect bag or one with straps or a harness.