Road biking and mountain biking are as different in style as they are in culture.
Road biking requires cyclists working together in order to maximize their performance through drafting and other strategies. In my experience, the drawback is that in contrast to working together to get a better time, road biking can be very "every man for himself" when it comes to helping others with mechanical issues.
Mountain biking, on the other hand, seems to have a culture of assisting anyone who looks like they are struggling, in spite of the need for individual talent and achievement in order to excel at the sport.
There is no drafting on an intense section of single track. I have been lent tools, tubes, chain parts, tech tips, and encouragement during various rides when things have definitely not been going well. Many of these offers came entirely unsolicited from complete strangers who just happened to pass me and my friends when we had stopped to deal with a situation.
After the break I will, in the true spirit of mountain biking, share a few of the more unusual repairs I have encountered when either parts or tools have not been present to do the needed repairs properly.
Flat tire, no tube
My brother-in-law, for his birthday, decided he wanted to bike from a starting point near his home to the beach. This would take our group of 10 over the Santa Monica Mountains and down to the beach, where our wives would retrieve us with cars.
Everything went fine until about halfway through the ride over the mountains, when a cousin got a flat. We had between us 4 tubes, 3 patch kits, a few CO2 cartridges, and 6 pumps. Sounds like an easy fix, right? No.
The size tube that was needed to replace the flat was not one that we has with us, so we opted for the patch; 3 patch kits later, we gave up on that route. We put in an undersized replacement tube that worked for a few minutes, until it got a pinch flat going around a curve in the trail when the tube got trapped between the tire and the rim.
It was decided that sacrificing the other tubes was just going to be silly. That was when the friend of a friend remembered hearing of another approach for an emergency fix.
First we put the original bad tube back into the tire. The we took grass and light brush and stuffed the tire with it. We made sure that we chose thornless vegetation, in order to minimize damage to the rim and tire. After a couple of re-stuffs to get the maximum amount of material in the tire, we turned around and set off for home.
The tire ended up looking half flat as he rode, but it worked fairly well. As the brush broke down under the wear of riding back, we re-stuffed the tire two more times before we got back to our starting point.
After the ride, our cousin immediately took his bike and dropped it off at a shop to get the tube fixed and his bike tuned up. While the shop reported that the tire and rim had suffered no damage due to the support given by the vegetation, they did laugh themselves silly when they discovered the contents of the tire, and they called our cousin to demand an explanation of just what had happened.
You should always carry a patch kit or replacement tube and an air source whenever you go out riding, but if you are ever caught without them and have a flat, remember that the trail-side vegetation can be used to get you back to civilization. Just avoid packing your tire with poison ivy, and be prepared to explain yourself if anyone happens to catch you before or after you stuff it.
Broken chain, no tools
How many people remember the old SNL skits about Lothar of the Hill People? I swear my brother-in-law and I channeled the spirit of the skits when I snapped my chain when I first started riding. This was the first time I had broken a chain, and was about the fourth off-road mountain bike trip with him. He had not packed all his tools, because it was going to be a quick ride; I had none yet, as I was not sure about how often I was going to be doing this. Halfway through the ride out, I broke the chain.
As we both stared glumly at the forlorn chain where it lay in the dust, we contemplated the long walk back to the truck. Matt suddenly picked up 2 rocks and announced that he was going to try to fix the chain. I laughed, but he proceeded to thread the chain through the derailleurs and sprockets.
After it was all set up, he laid the bike down, placed a large flat rock under the bent link, and used the smaller rock to pound the chain back together. I was nearly in tears laughing as I watched him re-enact a scene that smacked of the ape sequence from 2001: A Space Odyssey; I could almost hear Mike Myers cheering him on over the pounding movie soundtrack.
It did work, though! He managed to partially re-seat the pin back through the plates to effect a partial repair. I spun the tire and shifted gears while holding the bike's rear tire in the air to get it into an easy gear for a slow cruise back to civilization.
We had to "fix" it one more time before we got all the way back, but it was worth it for the story -- and for not having to walk all the way back. It taught me that even "short" rides need to be taken seriously, and to never leave home without all the tools you might need.
The worst "fixable" breakdown I have encountered is the dread "taco tire." This is when you hit something so hard that you cause the rim to fold over onto itself sideways. It is not easy to do, and it is harder to fix. The only real repair is to take it to a bike shop, and get a new rim. But if you find yourself stuck on a ride with a "taco" on your hands, I do have a "possible" solution.
The case I know of occurred on a long ride where carrying the bike out was literally going to be an all day project. This forced one of the ride participants to think "off the trail" to come up with a solution.
The rim was a loss anyway, he reasoned, so why not use a hard surface to try to bend the rim back into shape? He broached the subject with the bike's owner, who was willing to risk damaging the hub in order to not have to walk many miles to get back to his car.
The wheel was removed from the frame, and the hub was placed against a handy boulder. The beefiest member of the ride then put all he had into forcing the rim back into a shape resembling round. It took a few tries, but after the front brakes were disconnected in order to allow the still-tweaked rim to spin freely, it was serviceable.
Losing your front brakes is not a desirable outcome, but it beats an all day hike carrying a 25lb bike. Also, his brakes were not disc. That could inhibit this desperate repair as well, but it is good to remember that no matter the incident, it is usually possible to come up with an idea to make things easier... if you are willing to be unorthodox.
I hope that these stories brought a smile to your face, and that you never need to use these repairs. Be prepared. Take all the tools you might need every ride, but remember that even when things go wrong, there is probably a solution -- if you look hard enough for it.