Spare tube: Sometimes, a tube is just too damaged to be patched, or has had a failure such as the valve stem breaking off which isn’t something that can be patched. To save weight and space, I usually keep a lightweight version of the right size tube for my bike. Since one of the first things I do with most bikes that I own is switch them over to heavy-duty thorn resistant tubes, I just take one of the originals and put that in the toolkit.
The best type of bike for exercise depends what level of rider you are and whether you would rather ride on trails or on the road. There is a type of road bike that is called a “Fitness Bike,” and features a lightweight frame and narrow tires, but do not have a drop handlebar. This may be the best type of bike for someone who intends to ride regularly and strenuously on the roads. If you plan to do a lot of trail riding, the best bike for exercise would probably be a mountain bike. For a person who uses bikes for transportation and exercise, but doesn’t go off-road, the hybrid bike build is a good type of bike.
Next to everything else that might go wrong with a bicycle on an extended ride, a flat is a relatively minor issue that can be easily repaired trailside, if the right tools are at hand. If they aren’t, a quick fix can turn into a long walk. Well-prepared riders will perform a tune-up regularly and clean their bikes after every ride. For the less-diligent, a well-stocked repair kit will suffice.
Brakes come in a variety of designs depending on the age and style of your bike. Rim brakes offer more modulation but have less stopping power, so are more suited to riding on the roads. Disc brakes can provide huge amounts of stopping power so are best suited to off road riding, although ‘V’ rim brakes are also well suited to mountain biking. All brakes use a friction system to stop the movement of the wheel, so regular checks of the contact pads should form part of your regular cycle maintenance.