You should choose yours based on several criteria: the capacity, waterproofing, and compatibility with smartphones/tablets.
What to Look for
Enough space for what you need – i.e. you’ll need a much bigger bag if you want to bring back-up gear or bits for your bike, but can get away with something much smaller if you just have your gloves and headphones to carry – as well as whether it’ll protect your things from the rain (do you even need it to?), and whether it has a pocket or compartment that will keep your tech safe.
This is determined by the quantity and size of the accessories you want to transport.
A saddlebag can hold around 0.4 litres.
A handlebar bag generally holds between 2 and 6 litres.
Frame bags hold around 1 litre.
There's a difference between water repellent and waterproof .
If a bag is water repellent the fabric will ‘pool’ water on its surface, and the faster water runs off without soaking through, the higher its water repellency.
Waterproofing is the fabric's ability to prevent any water – whether that’s rain or snow, dew or water vapour – from penetrating it, therefore keeping the contents of your bag completely dry.
All B’TWIN bike bags are water repellent. However, only some of them are completely waterproof, so be sure to read each one’s description.
Compatibility with Smartphones/Tablets
Most people don’t want to be far from their phone or tablet, whether that’s for entertainment purposes, so you can call home or upload pictures from your ride to Instagram, or even so you can use it as a satnav, so it’s important to choose a bag that can carry your tech safely.
Look out for frame and handlebar bags with a specific transparent compartment for carrying and using your smartphone or tablet when you are on the move.