Bike Bag

I am fully committed to my cycle commute now and am in search of a new bag. It's only 20mins from the station to work and it's the best wake up call you can get. Even when we move I am still hoping to catch the train and judging by the traffic it would be better to park and cycle than try and commute in.

So far the bike is costing a lot more than the bus. I have had a service done, new chain, sprockets, back wheel and brakes. I have purchased some waterproof over trousers, and the downpour today proved that was money well spent. I have LED lights and a lock, both essential. This all adds up but at £12 per week so did the bus. I have yet to calculate the break even date but I am thinking sometime in the spring.

This leads me onto the next purchase. The bag. I currently have a nice backpack that fits my bits for work very nicely but it has a couple of problems. The main one being it's a backpack and so I get a little warm while cycling. It also is not waterproof so things get a little damp inside. Now that I am cycling I also need a couple of extra bits such as my trousers, a bungee chord, a pump, some lights.

After a weekend of research I think I have concluded that a pannier is the answer and a briefcase one at that. I did look at messenger bags as I was a little worried about the vibrations and my laptop but loads of people take their laptop in pannier and don't have problems. I want to get the bag off my back and a messenger bag seems a bit of a compromise for me.

There are a few briefcase panniers available, one from each of the major manufactures, each one is basically the same format. A large box shaped bag that mounts on the back of the bike at an angle so as not to get in the way of your heel. Differences seem to be, size, material, internal padding and closure.

I want it to be fairly big as I may need to take some extras so the compact bags are out. They are all made of some sort of waterproof material so there is not much to choose there but the way they look. Internal padding is quite different with some have hard edges with nuts sticking out from the mountings and others having padding and sections built in. Closures varies from the drawstring and lid to the roll top drybag style.

I have been in to a couple of shops and poked a few so I have a fair idea of whats there but I am still undecided as to what to go for.

Any ideas?