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.
Mini Pump: This actually goes on the frame of your bike, as it’s a bit too big for most under-seat bags. Coming soon, we’ll have a review from Bill of his very favorite one, but a good pump is a lifesaver. Some people instead carry a CO2 inflator, which is faster and easier to use but does require disposable cartridges, and each time you have a flat, you’ll need at least 2 of those cartridges. There are combined pump/inflator tools that we’ll also talk about soon.