Tank Bags are generally not made from leather but rather from synthetic water proof materials that either have a waterproof lining or come with a cover that fits of the tank bag and protects it from the rain.Motorcycle Saddlebags are usually the more popular choice on cruiser bikes because these types of cycles are made to have some sort of storage system mounted. When making a choice on what you get keep in mind what your purpose is for getting the bags. If you just want them for trips when you go out of town then you want to look at a set of luggage that is easily removed. Lots of those are available or choose a permanently mounted system which ties in to your bike and is not easily removed.Usually if you get something that is permanent its not just for storage but also to enhance the looks of your cycle. A nice set of leather motor cycle saddlebags should do that quite nicely. On the other hand if you just want something to throw on the bike for longer trips I would look at a set of touring luggage which will give you the most storage and will easily mount on to the bike and just as easily come off. That way when you get to where you are going you can shed the luggage and leave it at the site or your hotel room and go out and tear up some road.Now for Sport Bikes a tank bag is usually the easiest way to create storage for yourself. Magnetic mounting systems are usually used on these making it easy for you to mount the tank bag and remove it. I have however herd that some magnetic tank bags can interfere with your electronic fuel injection system since it is a computer and magnets do affect that. Having said that I have a magnetic tank bag on a fuel injected bike and have never had a problem. If you are concerned about this I would go and get a tank bag that has a different mounting system.There are a few that dont use magnets however most of todays tank bags will use a combination of magnet and some sort of tie down to keep the bag in place. Generally on sport bikes just the magnets in the bag are enough to keep it place since it is usually sitting behind a fairing the wind does not effect it however I have used a tank bag on my cruiser and it needs an extra tie down that snaps on and ties down around the neck of the bike to keep it in place.Most of your tank bags these days are made from synthetic material that are waterproof and protect your gear from the elements. Another convenience factor on most of these bags is that they generally have a handle and even backpack straps are part of some, so you can easily pull them off your bike when you need to go inside of a place. Also I would recommend you look at the dimensions and try and find something that suits your needs. You can find tank bags that are big enough to fit several days worth of clothes and gear or a small bag that is good for tooling around town or a day trip. You will find most of them are expandable this makes it versatile enough to use for different applications.There are many manufacturers of motor cycle saddlebags and tank bags to choose from. I will list a few of the ones I know here: Chase Harper, Nelson Rigg, Saddlemen, T-Bags, Hopnel, Dowco, Willie and Max, Kuryakyn, Ace, Axio, and Iron Horse.