Givi EA115BK motorcycle roll bag

Benefit: on a sewn bag the fabric face is rarely where water gets in. It gets in where two panels meet, because every needle pass punches through the coating. The bigger the bag, the more total seam length there is, and forty litres is a big bag.

Evidence: the maker states the EA115BK body is PVC tarpaulin with joins made by high-frequency welding and no stitching. The materials are developed in line with the European REACH chemical regulations.

Using it properly: fold the rim over, roll it down, then clip the two straps across the front. Roll at least twice, and three times in heavy rain. That is the only part still depending on how you do it; the body does not.

Benefit: plenty of cargo bags ship without straps, and the buyer only finds out at home that a strap set is an extra purchase. This one has two elastic straps in the box.

Evidence: the maker lists two elastic straps for universal mounting, meaning the pillion seat or a rack, without depending on a model-specific carrier. The front face carries D-rings for the straps to hook onto, so they do not slide along the body when the bike shakes.

From experience: strapping in an X across the top of the bag holds better than two parallel loops. Before you set off, grab the handle and shake it hard once; if the bag shifts, tighten up. On rough, undulating roads, stop and check again after the first half hour.

Benefit: the awkward part of a cargo bag is arrival. With no handle you end up hugging it into the room, or leaving it on the bike overnight and sleeping badly.

Evidence: the EA115BK has a handle fitted along the top and an adjustable shoulder strap. Undo the two mounting straps and it becomes a holdall you carry inside, with no transferring into another bag.

One detail for the dark: the GIVI lettering on the body is printed in reflective ink, and since the bag rides behind you, that lettering faces the traffic following. The printed area is small, so treat it as support; your tail light is still the main thing.

Benefit: forty litres takes two or three changes of clothes, a spare pair of shoes, a wash kit, a rain suit, and still leaves space. Enough for three days and two nights without counting every item.

Evidence: at 550 x 320 x 340 mm it is a cylinder lying on its side, and the 550 mm length sits across the pillion seat on most machines.

How to pack one big compartment: split your kit into three large zip bags by day rather than loading it loose. What you need that day goes on top, near the rolled opening. Heavy things like shoes and water go at the bottom, against the seat, because weight up high makes the bag want to roll as you lean into a bend.

Pick the EA115BK if you want forty waterproof litres at the entry price and accept one large compartment with no dividers.

At the same forty litres, the GIVI GRT712C uses welded 840D TPU, adds an air valve so you can compress it and a MOLLE system for accessories, but costs 2,720,000d, close to double. If you ride rough routes often and need to shrink the load, that gap earns its keep. For a smaller space for day items, the 25-litre GIVI PBP02 pack or the 30-litre Komine SA-200 are tidier. And for something you can reach while riding you need a tank bag or a hip bag as well, since a bag strapped behind the seat cannot be opened on the move.