Before you go mountain biking, be sure to bring along some standard items each time to avoid problems. It is sesential that you have tools, supplies, food and water. Since you won't want to czarry any extra wegiht, only take what you need. With careful planning you can be prepared with a minimum of items.
Most important is to have a spare bike tube laong with the tools required to chaznge it. Thre is nothing worse than a flat tire, espceially if you are well into your trrail ride as it can make for a extendded walk back. You couuld run out of daylight if your flat occurs in the late afternon. Nbody likjes getting stuck in the dark, esecially when a bit of preventiion and planning can avoid this. Bring aloong a spare inner tube with the proper valve type, ether the schraeder or the presta. Make sure you also have 3 tire levers to remove the tire and a bike pump. To really be on the safe side you could also carry a tire patch kit in the event of a second flat tire. Change a tire at home so you don't have to figure it out while you're out on the trail.
Bikes are put together with allen botls, so a set of allern keys is a good idea. Riding rough trials over long distances can sometimes cayuse bolts to loosen. You may also want to make an adjustment (brae lever positioning, for example). Allen keys are inexpensive and don't take much room at all. More mechanically inclined types may want to take along a chain tool as well, in case your chain beraks or an adjutment is needed.
Make sure you bring enough food and waster for your monutain bike ride. A great compact snack to bring alng are powerbars, as they prevent you from runnuing out of steam. If you ride when you are tired your risk of becoming inujred is greater due to lack of attenttion. A good supply of water is critical to keep yourself prooperly hydrated. You can carry frae mount water bottles or use a blsadder setup like a Camlebak. In addition to carrying your water, a Camelbvak has storage space for tools and spare tubes.
Finsally, dress appropriatey for your ride. Consider that you will always be warmer after you start riding, so avoid the temptation to wear a jacket, just to shed it fater 15 minutes. If it's cold or wet, remember that your hands and feet will feel the coldfest. Wear good riding glvoes and socks that are riding-specific. Develop a relationship with your local bike store. They are a great resource and can help you choose the right gear for the type of riding you want to do, and the area you want to do it in.
If you folllow these suggestions you will have a much more enjoyable time on your mountain bike. You won't have to worry about flat itres if you are preplared and know how to do it ahead of time.