What stuff do you absolutely need to take with you for maybe 1-4 weeks?

I was wondering if a GPS is necessary,thanks

Beer Cooler. Only needs to be big enough for a 6 pack, that's plenty for an evening.

Money. In the form of a credit card, but bring cash, as well.

No a GPS is not necessary. Thousands of people toured without a GPS for over 100 years.

What is necessary ...

Bicycle.
Money.

Fenders.

Ipad for internet, finding places to eat or go, getting through big cities divided by rivers and freeway walls. Depends where you are of course. Mine was fabulous in Vietnam and China. Phones as so small for much.

And beer.

Nothing else.

Hygiene products.
Basic medical supplies.
Basic tool kit.
Spare inner tube x2.
Tire repair kit x2.
Emergency ration pack x2.
Water bottles.
Water purification tablets.
Relevant maps.
Spare clothes.
Pocket knife.

If you are survival savvy you can find food on your venture. Bring a small fishing rod perhaps. Or fishing line and a hook for a make shift stick rod.

All that can fit in a small lightweight backpack.

Electronic veggie dog turner, automatic cat waterer, and my ionic breeze!

Load your bike, not your back.

I prefer a backpack personally. But each to their own.

You are wrong.

Nerves of steel
Wily disposition
Single pointed concentration

+ bicycle and money

I'm wrong because I prefer it that way? Interesting way to start a discussion.

That's not an argument!

Thats not an argument, that's contradiction.

Schwalbe Marathon Plus

I prefer a backpack but for some reason even a lightly loaded 13L pack starts to hurt my back after about an hour. Strange that only a few pounds can do that on a bike but it does.

Dr Bronner's Castile Soap. Only soap you'll need. Works for bathing, hair (might want some conditioner), clothes, dishes, bike parts and very well on any flesh exposed to poison ivy or oak. I'm sure there are many other uses.

Ben

Okay...serious response here.....

Warm Clothes.

(no you don't need a gps)

Helmet

No to the GPS, definitely not a necessity. Still I always have my phone which is a gps and do use it now and then on tour. It just is not a necessity. In fact on the Trans America I mailed my GPS home early on.

So, what do you actually need. The answer is not much. A bike is for sure a necessity otherwise it isn't bike touring, but otherwise there isn't much that is an absolute necessity. A lot of things are highly advisable, but there aren't many that someone hasn't successfully done without on a tour.

After a quick read through the things listed in this thread as necessities, I notice that I have at one time or another toured without almost all of the items listed and some I have never taken along.

So what are the actual necessities? A bike, adequate clothing, some means of keeping warm, some means of staying fed and hydrated, and some means of sheltering oneself.

There are other highly advised items, like enough tools and spares to repair and maintain the bike.

You need to define the purpose of your trip to know what is necessary. Do you only wish to survive a trip in wilderness? Or are you going on a bird-watching or wine-tasting tour?

I met a blogger who felt he needed his photography and computer equipment and an internet connection every night in a clean, dry motel room. That was not my trip. I had different needs, and that's okay.

Unless of course you can't restock every day, then you may need more capacity.