It may be that your bike is beyond repair, or one member of your party is injured sufficiently badly that they can’t walk out. If that’s the case, you need to make contingency plans for getting back to civilization.
Find your current location on the map
Work out where you are, so that you can plan an escape route, or you can give the location to a rescue party. Write the coordinates and/or GPS location on a piece of paper.
Check escape routes on the map
Hopefully you studied the map before you started. Now is the time to find a good route out. It may be that retracing your steps is fastest. It may be that continuing on your planned route is fastest. Occasionally there may be a faster way out, but remember: search and rescue parties will expect to find you on your planned route, and any new route you take may well include an barrier such as a fast-running river or a ravine. Only take an escape route if you know it will be faster than your planned route and equally safe.
Carry the bike
‘Cross style – as used in Cyclocross races. Good for short distances and on-and-off riding. Put your right arm through the main frame triangle from the left side of the bike, and hoist the bike on to your shoulder. Grasp the right handlebar grip with your right hand, and make sure the left pedal is facing backwards so it doesn’t dig you in the kidney. You now have a stable bike and a free hand. If you have a backpack, make sure the top tube rests on the backpack strap. Otherwise, use padding if you will have the bike on your shoulder for a while.
The bike is still pointing forward, so it doesn’t take up much trail width. However, bottle cages and some suspension systems get in the way of the ‘cross method.
Hiker style – this leaves both arms free, but requires a wider trail. If you have great balance, you can potentially carry one bike this way while riding another. Take two inner tubes (or backpack straps, or whatever you have available), attach one to the steerer tube between the top and down tubes, and one to the top of the seat tube around the seat stays. If you are using tubes, you can loop them through themselves to do this, and they are soft and springy enough to provide comfortable suspension against your shoulders. Now bring the tubes down the left hand side of the bike, underneath the bottom bracket, and loop them over the right hand crank arm (which should be pointing downwards). Remove the left hand pedal, then put one tube over each shoulder like backpack straps. The weight should be fairly evenly balanced left to right.
Last resort: Stash the bike
You love your bike, but trying to drag it out may slow you down too much. If necessary, find a place to stash it slightly off the trail and out of sight, but with sufficient landmarks for you to find it again.
If members of your party are hurt…
Send part of the group off for assistance
If you have an injured person in the party, evaluate whether it is better for that person to try and walk out, or whether you should wait for assistance. If you do send part of the group off, make it clear where they can expect to find you when they return – either at your current location or at a predetermined pick-up point. Give the people who will be leaving a copy of the coordinates that you wrote down earlier.
HOWEVER, never send one person off alone. Never leave an injured person alone. If there are only three people in your group, stay together and wait for rescue. You are already tired and panicked. The chances of further injury are too great if you split up, and injured people often do crazy things if left on their own.
Stay where any rescue group will expect to find you
Assuming you told someone where you were going and what time you planned on returning, they will most likely alert the authorities if you are out a lot longer than expected. If nobody knows your route, and you decide to send part of your party for help, don’t stray from your agreed plans after they have left. Changing plans minimizes your chances of rescue.