Bicycle care and repair. Help needed please?

Question

I have a bit of a dilemma and would like some helpful advice.

The chain came off. I managed to get it back on now the gears will change up, but not down.

Also the brakes need adjusting and/or changing.

There's no instructions in the manual on how to deal with either and the nearest cycle shop is too many miles away.

There are 6 gears and the rear brake operates from the side if that's any help.

Answer 1

Alright, I'll try and write this using the most basic terms I can think of.  But before we get into fixing the bike, you need to ask yourself why the chain fell off.  

You may not know why, which is OK.  It happens sometimes and there is nothing you can do about it.  You should be more concerned if, say, you hit the part that pushes the chain from one gear to the next (this part is called a rear derailleur).  If you didn't give that thing a good whack, don't sweat it.  If you did, you may have damaged it and in your case should take it to a professional to fix or replace.

Alright, lets assume you've done no serious damage to the derailleur.  If your gears are not changing down, that tells me a few things can be wrong.

The first thing has to do with the cable that attaches the rear derailleur to the the shifter itself.  It is possible that something is clamped down on the cable hindering the return movement that derailleurs make when down shifting.  Follow the cable and make sure nothing is hindering it's movement.

The next thing, and most likely, is the bolt that clamps the aforementioned cable to the derailleur is loose.  This is an easy fix.  You will need a hex key or variety of allen's wrenches to figure out the correct size for your particular bolt and some sort of pliers.  Set the shifter so the cable leading to the rear derailleur has the most slack (so that it is on the lowest gear setting which would make it easiest to peddle).  Loosen the bolt which clamps down on the cable (most likely you will have another piece attatched to the bolt which does the actual clamping).  Use the pliers to pull the cable taught and tighten the bolt (it should be pretty tight).  Yes there is a special tool for doing this but trust me you are fine just using pliers and the allen's wrench.  This should do the trick if that's the problem.  This might help explain this more:

http://en.wikipedia.org/wiki/Rear_derail...

If not you might have a problem within the shifter itself.  This is something you may be able to fix on your own although explaining it without actually demonstrating what to do is pretty hard.  Easiest thing to do is pull on the cable at some point where it runs along the frame and see if it comes out of the shifter.  If so your best bet is to take it in to your local bike shop.

There are other things that could be wrong although those are the three most likely in my mind.

Now your brakes are a different story:

Check the brake pads to see if they have teeth.  They should have prominent nubs that hit the rim as you brake.  If those have worn down it may be time for new brake pads.  Also see if they are hard as rocks.  They should be somewhat gummy.

Adjusting your brakes really depends on the type of brake you have.  If you have a road bike you want to loosen the cable which connects the brake to the brake lever (you didn't put away those allen's wrenches and pliers I hope).  Now for the tricky part; use one hand to close the brake pads towards the rim (the pads should be very close to the rim but not touching it).  Use the other hand to pull the cable tight.  Without releasing the pressure from the hand pulling the brake towards the rim, tighten the bolt that that clamps down on the cable on the brake.  This is hard to explain so that it makes a lot of sense but what you are trying to achieve is a very small gap between the brake pad and the rim when the brake is not being applied.  Doing so will give you considerable braking power.  I've done a little online looking to see if I could find some helpful pictures:  

http://www.ehow.com/how_117887_tighten-l...

http://en.wikipedia.org/wiki/Bicycle_bra...

If you have the other type of brake (a pull brake which is found on most mountain, hybrid, and cyclocross bikes) it's a different story.  Adjusting them may mean aligning them.  There are little screws on either side of the brake arms which allow you to do so but I don't recommend messing with those if you don't know what you are doing.  More of a hassle than it's worth.  

Good luck!

Oh, and the Sheldon Brown website is a terrific resource for all things bicycle.  I built my first fixed gear bike almost completely based off the information from his site.  They guy really knows his stuff.

Answer 2

You have bought this mailorder?? if so. now you are finding out why its not a good idea, ring them up and tell them you are totally dissatisfied and want your money back, when you have it in your hand, ring the local bike shop,(How many miles is too many?) and ask them what they can do for you, they may even deliver!!

You will get a fully assembled bike, ready to ride without hassle.

Answer 3

The first place I check whenever I want to find out basics on maintaining my bike would be Sheldon Brown's website, which is an invaluable trove of information on bicycles.

His excellent page on adjusting the derailleurs on your bike:  http://sheldonbrown.com/derailer-adjustm...

His page on adjusting brakes:  http://sheldonbrown.com/cantilever-adjus...

Hope this helps.