A wrench that fits the hub nuts: If your bike has quick release front and rear wheels, you don’t need this, but if you have an internal hub on the back, such as the NuVinci, a wrench that fits is a great idea. 99% of the time, this is a 15mm wrench, but you should check your bike. A 6 inch adjustable wrench can also work, but it will be heavier, and when using an adjustable wrench, you do need to take more care to not round over the nuts. A fixed wrench is the best choice. Some multi-tools have a 15 mm wrench built in, but again, if you have limited hand strength, something with more leverage is a great idea.
If you have just a short time in Seattle there is only one way to see the city. Walk at 2.5 miles an hour? I don't think so. Take buses and trams that you have to wait for and that might not even get you where you need to go? No way Jose. Drive your car? Hahahaha get outta here, don't even talk to me. But what about a BICYCLE??? Now that's the ticket. The Bicycle Repair Shop does rentals by the hour or by the day. They have reasonable rates. They have solid, lightweight hybrid bikes so you can tackle train tracks and brick streets and hills. They also have road bikes for the more experienced. You can reserve online in advance. You get a helmet and a lock with your rental. The staff in the shop are friendly and will suggest routes and point out hills if you're new to the area. And believe me these hills are no joke! I had a great time in Seattle and it's all thanks to this business. Next time I visit I am definitely doing this again.