Pannier or large saddle bag for commuting?

The OP updated his original post. At first it read like he commuted 160 miles in a day.

I've got the Carradice Camper Long Flap which I use for commuting. It might seem excessive given it's their biggest bag - but I take a towel to shower at work and my work clothes, as well as lock and various bike bits so it's just about the perfect size. Then if I want to take it away for a weekend I have the option of expanding it.

I'm off to Scotland tomorrow for a week and my only luggage will be the Carradice and a 7 Lt Ortlieb bar bag. Granted, I'll be staying with friends and family while I'm up there - but I'm really putting the idea of ultralight packing to the test

I have a similarly long commute and went from rucksack to panniers (Ortliebs, they're brilliant). Most of the time I'm using only one of them (and yes, your brain quickly compensates, even if the pannier bag is fully loaded).

The rack is quickly removed if you want to take it off for the weekend. But then, if you don't want to be faffing about with one at all, a carradice certainly makes sense. Personally I'm quite fond of the additional cargo capacity of a set of panniers. Can do all my groceries shopping by bike too.

A single pannier, lightly loaded, is hardly noticeable. TBH even a heavy load doesn't matter much, as your brain's balance center naturally compensates for any slight list the vehicle might have. The only thing it affects is how often your bike will fall over when you park it against lamp posts.

+1 again for Carradice.

I use this:
http://www.carradice.co.uk/index.php?page_id=product&under=type&product_...

Nice and easy, quick release, waterproof, also saves your @ss from road spray. The mount weighs nothing on your bike - great for when you're not riding with luggage.

I've even done weekend credit-card touring with it (shoes, jeans, t-shirt, thin hoodie, underwear, small tool kit/spares) - just! So plenty big enough for commute duties.

Also, in my experience you will get excellent service from Carradice if you ever need it, I posted on here recently that I lost the spring from my quick release system while cleaning my bike, 1 email to Carradice (reply took 2 mins!) and a kindly person there sent me a replacement spring free of charge - received the next day!

+1 for carradice.

At first look they are expensive for what is effectively a canvas satchel, but get one and you'll realise they're worth every penny. I have a Pendle, it's about 11 ltr and apart from the occasional waggle when I'm out of the saddle I barely notice its there. Plus it goes really well with my Brooks, I had to get a black one though because I have a black saddle (would love the olive/green, but I thought it would clash). Make sure you get one of the fixing systems though as they are well known for the "carradice sag".

If I needed to carry more, I have my old Ortlieb panniers and a rack. I personally don't like how heavy it makes the back end feel once they're on though.

I used 2x Ortlieb front roller panniers (the classic) for years of commuting, various jobs, between 8km and 30km each way, never had a problem.

Colleagues often ask, "oh, are those some kind of special bicycle bags?" when they see them, or even, more depressingly, have absolutely no idea what they are.

Now my commute is bike free so it's rucksack, train, and microscooter

I use a Vaude pannier that converts into a rucksack when you're off the bike. Lots of 'slots'/sections for things and I think they do different sizes. Very sturdy and has a waterproof cover. I came off last year and the bike skidded across the road on top of the bag; not even minor damage. I think Altura have produced something similar. If you want holdall style panniers, then Ortliebs are the only option. Totally waterproof and 'bombproof'. Mine are 15 years old and still going strong. I've seen some pretty stylish and functional Brooks panniers as well, but at a price! Panniers are the way to go and, contrary to some opinion, don't slow you down. I'm sure it's just 'image' for some people who can't bear to look like a 'shopper'.

If you can fit a rack easily enough then panniers are the way forward. I don't have stays for a rack on my commuter and I like to take it out on longer runs at the weekend, so I use a Carradice saddle bag to carry my gear and the SQR system so I can whip it off easily enough when I don't need it. They aren't cheap, but when you consider the back pain and sweatiness caused by wearing a rucksack it's worth every penny.

I'm assuming you don't actually commute 160 miles.

The lower you can carry weight the better, so if you can fit panniers then great.