Problem with my bike
I'm having a problem with my bike. I always "slip" gears. I'll be riding along in, say, 4th gear, and all of a sudden it will slip to 5th gear (with quite a jolt, too, which has been the cause of some accidents ). I've taken to riding exclusively in 7th gear, since there's nothing for that to slip into. Is there anything I can do? If it's really difficult to fix, could you give really step-by-step instructions, because I don't really know anything about bikes.
There could be few things that are out of whack. The most like likely ones I can think of are the cable tension of your rear derailleur (this can be easily adjusted by screwing the derailleur's barrel adjuster in or out), the alignment of your rear derallieur hanger, a worn chain, or a worn cassette. It may be one, or a combination of these possibilities. The hanger alignment is best done with a special tool, so you best take it to a shop. A worn chain or cassette simply need replacement (you should do both at the same time).
Sorry, I'm not too good at giving written instructions, but the barrrel adjuster aligns the rear derailleur cage/pulleys with the appropriate rear cog (gear) by loosening or tightening the derailleur cable. If you screw it in, the cage/pulleys will move down toward the smalled-toothed cogs. If you unscrew it, it will move toward the larger-toothed cogs. Aw crap. I probably just confusing matters. It might be best to find a friend who can physically show you how to do it. It's much easier that I make it sound. A good bike repair book like the one by Lennard Zinn will help lots too. Good luck.
Darailleur? What's that. I told you I was dumb with bikes.
Originally Posted by Chongo
This problem is recent. My bike didn't come with this problem. Does this make it more likely that it is one problem instead of the other?
How much do you think it would cost to take it to a shop to get the hanger aligned, so I don't get gyped.
Thanks for the book recommend. I'll see if my libarary has it or something similar so I can see what you're talking about.
If you have indexed shifting (separate click on the shifter for each gear), the shifter probably needs replacing. If you have the older friction shifting (gradually move the lever till it goes into the next gear) you need to increase the friction in the shifter by tightening the screw in the middle of the shifter. This screw usually has a D ring on it so it can be done while you are riding without any tools.
Do you have a friction lever or click shift?
I guess it's a click shift, based on that description. It's really random, though. I don't know, but to me it seems that if it's a shifter problem it would slip gears while I was shifting, which is not what's happening. Then again, I don't really know.
Here's a link to the Park Tool website that may help: http://www.parktool.com/repair/readhowto.asp?id=64
I keep forgetting to include things. Anyways, the derailleurs are the things that move the chain up and down the gears. There's one in the front, and one in the back. The rear hanger can get out of alignment if you've crashed the bike on its right side, or if something has banged the rear derailleur. The Park Tools website has nice pictures too.
all u have to do is play with the barrel adjuster. the parktool.com site is good. basically it's like this.
go to your rear tire. look on the right side. the chain goes through a thing that hangs off the side. that big thing is called the derailleur. follow the cable as it goes in and out. on one of the ends of the cable housing is a little barrel. twist that barrel counter-clockwise about half a turn.
Here's how I usually explain it to people, but it's easier if done in person.
Get you bike elevated in a stand (or have a friend hold it by the seat if you don't have a stand). Turn the cranks with your left hand (slowly), and slowly start shifting through the gears. Start in one, and work you way one at a time to seven. Now, shift slowly back to one from seven. Pay attention to how well the bike shifts.
Does it upshift (to smaller cogs) easier, or does it downshift (to larger cogs) easier?
Usually, when the cable tension is off, it shifts better in one direction than the other. It generally won't have a ton of difficulty shifting in one direction, but it will hesitate and/or skip in the other.
Once you determine that, put it in a gear it "doesn't like". Looking at the rear of the bike/derailleur, turn the barrel adjuster (where the cable enters the rear of the derailleur) in the direction of the trouble 1/2 turn at a time until the clicking/skipping stops.
Now shift up and down through the gears and see if it's better. There's a chance you have screwed the barrel adjuster either too far or not far enough, so continue tweaking the barrel adjuster 1/4 or 1/2 turn at a time. If it starts hesitating in the opposite direction, that means you've screwed/unscrewed too much, and you need to turn the barrel adjuster a bit the other direction.
It'll probably take you a bit to get the hang of it, but it's not rocket science.
You are probably also at a point where you need to replace the cassette and chain, but I can't be for sure on that.