Bicycle Maintenance. I think every rider has been on a shady ride at least once. From experience I've discovered that it's extremely difficult to race when you're worried about a chain popping.
This weekend I went to the akron Nationals to watch some of my friends race. A good friend of mine was having a killer day after coming off a win the day before. He had won his first two motos and was in line to transfer to his semi. As a top of the line 17 novice he ripped it up with a hole shot, until his chain popped in the first turn. Over the berm and through the woods to grandmothers house he went! That brings me to the topic of today's discussion. The chain.
I like to think of my bicycle like I think about my car. My car has a drive train, as does my bike. On my bike, the chain is one of the most crucial parts of the drive train. It's like the axles on a car, beat on it or forget to keep it lubed and eventually it will break. I've seen way too many rookies who think their chains broke because they were able to leg press 2000 pounds. In reality it comes from a variety of things.
The first chain killer is running a dry chain. You should Always use some kind of lubricant on your chain, even if all you have is WD-40. It's better then nothing. I've personally found Pennzoil (yeah that's right, motor oil) to do the job quite well. The only problem with it is that if used in excess it turns into a dust magnet that will make your bike look horrible. It also washes off fairly quickly if you have to ride in a mud race. The solution is to wipe the chain off once after you put the oil on it. Dry lubes that are wax based work well, but in my own experience they tend to be too noisy. I don't like the way my drive line feels when using a dry lube because it starts to grind and shift. It's very annoying personally.
On to the second device of drive line destruction. Poor chain alignment. This is a killer that's so easy to avoid, and yet happens so often. Having the chain aligned wrong can cause a couple things. The nastiest of which is a bailed rider when the victim throws his/her chain at speed. As my friend so happily showed us last weekend. The next is excess sprocket wear and excess chain wear which leads to a broken chain and lost power.
The process of aligning your chain is actually very easy. First you need to space your profiles properly so that the chain wheel lines up with the freewheel by changing the number of spacers between the bottom bracket, crank arm, and the sprocket. Next you need to take the time to space the sprocket and the crank arm at the small black bolt (this is all intended for riders who ride 3 piece cranks of the profile style). When I did it I got super technical and used a micrometer to make sure everything was spaced evenly to the thousandth of an inch. I don't recommend you waste your time like that, just get it all straight and true to the eye.
Now that I'm tired of talking about my chain alignment methods, I'll bring up one more common topic of drive train discussion. Chain tension. According to Jim Boswell's old school bike setup you should set your chain up to have almost one half inch of slack up or down. Here is how you do it. Find your tight spot with the chain setup to be tight. From there, loosen it up until you have around a quarter inch of vertical play in the center of the chain. Now it's tight enough to stay on, but not so tight as to kill your power. Remember to make sure it's aligned properly! I can't stress that enough. If it's not aligned you won't be able to run slack in it without throwing it!
The last thing you can do to save your body and your bike is preventive maintenance. I don't believe in this personally, but I probably should. Any ways, the more you ride, the more your chain stretches. You're supposed to replace them about every 4-6 months along with your sprocket. Don't worry about the freewheel unless it doesn't freewheel anymore. Replacing the sprocket is a good idea because the teeth wear and gradually deform over time. The combination of chain stretch and sprocket wear does take a toll on how much power you can get to the ground over time.
Next time we'll talk about 3pc. cranks, how to and how not to set them up. Feel free to e-mail your comments and suggestions to, bmxman_69@hotmail.com
The second column in the series
Not too bad for a young guy, eh? - JB