1??Spare Tube and Patch Kit:
The most common problem cyclists face is a flat tire. Always carry a spare tube and/or a patch kit with you. If your flat tire is caused by a small puncture, you??ll likely be able to use a patch kit to fix it. For large punctures and blowouts, replacing the tube is your best option. 
2??Tire Levers:
Tire levers help you pry your tire off the rim of your wheel when you??re fixing a flat. They??re especially helpful when you??re removing a road tire, as opposed to a mountain bike tire, because road tires typically fit very tightly on the rim. 
3??Bike Pump:
If you get a flat tire while you??re out on the road, you??ll need a way to inflate the tire after patching or replacing your tube. Always carry a small hand pump or CO2 inflator that will fit in your backpack or mount to your bike frame. 
4??Multi-tool: 
      A multi-tool can handle a surprisingly wide variety of repairs and its versatility makes it a good value. Its small size means it fits easily in an on-bike saddle pack or a backpack. 
      A good multi-tool has the following: 
     -A variety of Allen wrenches. 
     -An adjustable wrench, or open or hex wrenches (8, 10, 15mm are the most common, but size requirements vary depending on the bike). 
     -A chain tool. 
     -A Phillips screwdriver. 
     -A flathead screwdriver.