Front set doesnt change onto smallest cog, and rear set dont change at all,

Bicycles have two sets of gears (front and back). The 6 position control slides the chain between the 6 sprockets (cogs) on the back. The 3 gears are for the front set of cogs. Between the two sets of sprockets, you get 18 (theoretical) different rates of chain movement per turn of the pedals. In fact some of the settings overlap. (However some of these should not be used. Do not use the settings that pull the chain to the furthest inside of one derailleur and the furthest outside of the other. This diagonal between the biggest and biggest sprockets (or smallest to smallest) puts extra strain on the chain.) The back derailleur is in the lowest gear when on the biggest sprocker. The front low gear is on the smallest cog. The highest gear possible is on the smallest rear cog and the largest front cog.

By planning the shifts in gears, you can maintain the same speed and cadence (rate of pedalling) on different terrains. (For going up a hill, use a lower gear than on flat terrain. However don't go to low or the bike may not balance well.) To shift through a large range of gears, you must be pedalling and then move the rear derailleur control followed by the front derailleur then the back again. (For faster shifts to a low speed, you can shift the front derailleur first but that can stress the system.)

For a guide to using the gears: http://www.southcoastbikes.co.uk/articles.asp?article=Gears .

I hope this helps.

Cindy Wells

Don't start messing with the derailleur yet! Make sure your shifting trouble isn't due to something else, such as a warped, dirty, or stretched chain, gummed-up pulleys, crud in the cable housing, trapped cable, or a bent derailleur hanger
Clean the chain and the rear derailleur pulleys. Pull the chain away from each pulley, and turn the pulley to make sure it can move freely. A pulley that offers resistance to turning must be replaced.
Now check the cable to be sure it slides freely. Mud and grit within the cable housing, or on a cable-guide, can keep the derailleur from moving a "full gear" during downshifts. If the cable doesn't slide freely in the housing, you may be able to clean or lube it to restore smooth shifting.
Let the high-gear limit screw. In your highest gear on the shifter, and with the chain on the smallest cog, position the derailleur so the upper pulley exactly matches the teeth of the small cog. Run the chain a bit with the front derailleur in the large ring, adjusting the limit screw until the pulley and the cog seem to match perfectly.

Setting the high-gear (small cog) limiting screw.

Once you're sure the derailleur matches the cog, move it just a whisker (1/8 to 1/4 turn) towards the other cogs. (You may need to readjust a bit if you get chain-skip.)

Closeup of setting the limiting screw.

Now adjust the low-gear limit screw. Shift into the lowest gear (largest cog). If it won't go, loosen the limit screw. With the chain on the largest cog (and the front derailleur in the small chainring), adjust the derailleur so the upper pulley exactly matches the teeth of the large cog.Once it's perfect, turn the limit screw so it moves the derailleur a tiny amount towards the other cogs (1/8 to 1/4 turn usually works).

Setting the low-gear (largest cog) limiting screw.

Now shift to the highest gear (smallest cog). Push the shift lever to downshift one gear (go from the smallest cog to the next-smallest). If it doesn't shift, tighten the cable with the barrel adjuster, 1/2 turn counter-clockwise. Backshift and try again. Continue tightening until it shifts. If it overshifts, going from the smallest cog to the third-smallest, loosen the cable by turning 1/2 turn clockwise. Backshift and repeat until it shifts exactly from the small to the next-smallest cog.

Fine adjustment of tension in the derailleur cable.

Now go to the second-smallest ring. Tighten or loosen the cable slightly, until the outer side plates of the chain are just clearing the third-smallest cog. Shift up and down, fine-tuning until you're satisfied.

Checking the position of the chain on the cogs.

For the wide range of gearing on a MTB, the rear derailleur has to be able to adjust a large amount. If you shift into the smallest front chainwheel and the smallest cog on the rear (position 1), you'll probably see the chain is very loose and the rear derailleur is pointed back horizontally. Conversely, if in the largest front chainwheel and the largest rear cog, the derailleur will be pointed forward (position 2)
Couple things to do: 1) Avoid the gearing combination of the smallest cogs. Instead, use the middle chain ring and a larger cog (you'll have the same net gear ratio). 2) You can remove a link from the chain. A chain tool is about $10.00. You push the pin out through all but the last plate on two links, bend the chain slightly to pop those 2 links out (2 links = a wide link + a narrow link), then put the chain back together. This is only advisable if in position 2 there is some additional travel for the derailleur and in position 1, the derailleur has no additional travel. 3) Make sure your chainrings aren't bent, straighten (use a open-end wrench and gently pull the chain ring back to flat). This isn't likely b/c you don't indicate the chain falls off while shifting. 4). If the chain falls of the inside, screw in about 1/4 turn the inner limit screw on the front deraillleur. If the chain falls off the outside, screw in about 1/4 to 1/2 turn the outer limit screw on the front derailleur.

Neither screw is for mis-shifts. Those are limit screws for the largest and smallest cogs. Tweaking the cable tension will usually bring in the indexing...

http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

It sounds like your cable is/was a smidge too tight.

Congratulations on learning to ride the bike. I use the rear gears mainly i.e. the gears on the right hand side. Each rear gear makes a little difference so it makes it a little easier to go uphill. (When the chain is on the back smallest cog wheel it's hardest to pedal and easiest on the largest. The reverse is true of the front cog wheels) If you come to a very steep hill you should use the front gears i.e. the lever on the left hand side. This makes a bigger difference to the effort needed to climb a hill. When you have put the front gear into the easiest position, (on the smallest cog wheel) you can still use your rear gears to make it easier still. For going on flat ground or downhill most people keep both sets of gears on the hardest gear. (The front gears on the largest cog wheel and the rear one on the smallest) However there's no rule that says you have to. Use the one that feels you're using just enough energy to turn the pedals and in time you won't have to even think about the gears. I hope this helps.

Yeah you will run into that at some bike shops. When they see older components like that, they often refuse to adjust them for fear of breakage and liability. Try a different bike shop if you can, or if you are confident in your mechanical abilities, try it yourself, instructions here:
http://www.ehow.com/how_6086607_adjust-shimano-rear-derailleur.html

Good luck.

Hi,

This one's easy enough.. If you move the derailer through it's full stretch you will see that part of it will be blocked in each direction by a small screw. These screw adjusters are to stop the chain from running over the end gears, and sometimes if they're too tight they can stop the chain from reaching the gears in the first place.
A small screwdriver is all you should need, turn the bike upside down, loosen these screws completely and then change gear to one end first until it runs smoothly on the chain and then do the same with the other.
These are designed to be adjustable so you can add or remove gears/change wheel sizes etc and then readjust to run smoothly..

Hope this helps..

Front or rear? What is it doing?
Flip the bike over onto the handlebars and saddle and let us fix it.
Here is how to adjust the rear (first):
-Set your front gear to its middle position.
-Shift the rear into the highest gear.
-Disconnect the derailleur cable.
-Screw the barrel adjuster on the shifter (or down tube if it is a road bike) to fully turned in clockwise.
Screw the barrel adjuster on the rear derailleur to its halfway point.
-On the back of the rear derailleur you will see two screws. One will be marked "H" and the other "L". These mean high and low. Adjust high to get your jockey wheel on your derailleur perfectly centered over the smallest cog on the cassette. Manually shift by pushing the derailleur (while cranking the pedals) to the largest cog (1st gear) and set this stop on the derailleur "L" where the jockey wheel is over the cog, but past it where it would be touching the outside of the cog if they were side-by-side.
-Pull the derailleur cable taut and re-tighten it.
Shift the rear to the middle gear and adjust the derailleur using the barrel adjuster to center the jockey wheel directly over the cog it should be.
-Now shift up and down the cassette, cranking as you go and in every gear, back-pedal to make sure there is no problem with the gears hopping. If they do, adjust as necessary with the barrel adjuster.
Here are some tips for the front:
-Shift into low gear on the front and rear derailleurs. Make sure the chain is not rubbing on the front derailleur. If it is, adjust the screw marked "L" until the chain just clears the derailleur but does not touch it.
-Pull the derailleur cable taut and re-tighten it.
-Now shift the front into the middle gear and while it is still in the low gear in the back, crank to make sure the chain is not rubbing on the front derailleur. If it does, adjust the tension of the cable with its barrel adjuster.
-Shift the front into high gear and shift the rear to the highest gear, cranking as you shift. If the chain is not rubbing, you are all set.

It sounds like the limit screws on your derailleur body are out of adjustment. They are usually small phillips head screws on the body of the front and rear derailleur that limit the travel of the derailleur body on the rear so that the chain cannot get shifted into the spokes or off the smallest cog into the frame. On the front they prevent the chain from shifting off the inside or outside cogs. There are good articles under front and rear derailleur adjustments at this site:http://www.parktool.com/repair/byregion.asp?catid=53 I hope this helps.

shift onto your smallest cog on the rear and shift to your biggest cog at the front then place part of the chain onto the small cog at the back and then do the same with the big cog at the front then simply pedal forwards and the chain should go back on by itself