Bicycle Mechanics - Gear Problems

Hi again,
Something to try and help my sister out here, she has a full suspension mountain bike 15 speed.
She can change the gears from 1, 2 & 3 on the left side, and 1, 2, 3, 4 & 5 on the right side (if you know what i mean).

On the left side she can only put it on gears 1 & 2, and on the right she can only adjust it to 4 & 5.
I got on the bike to see what she was going on about, and it seemed as i changed the gears i could, they wern't actuary changing gears. So there I am riding along on this metallic pink bike which was pretty embarassing, pedalling my ass off and i wasn't getting no where, it feels as if its stuck on gear 3 or 4.

Anyone know what the problem could be, could it be a lose wire or do you think she is going to need a new gear system overall?

Thanks in advance,
Callum.

Could you tell us what kind of shifters the bike has? Are there little levers which change the gears or is there a twisting part on the handlebars? Could be a simple adjustment or seized cables or other causes. Maybe the local bike shop could give you an estimate. Are you determined to do it yourself?

I second tool boy here, we need more information. It could be a simple cable adjustment, could be the derailures need some tlc (also simple). Could be the frame is bent where the derailures attach... etc. Lots of possabilities. Most likely it's something that can be fixed. If you want to spend the time learning how to fix it yourself is awesome, but if you're feeling very lost, you might want to take it to a lbs, or see if you have a local friend who has more bike mechanics experience who could at least get you started on figuring out what's wrong.

Perhaps you could tell us more about the problem and we could help. What is the derailure doing when you shif the gears, what is the tension on the cable like, are the parts lined up with the frame correctly.... etc?

(Sorry to not be more helpful)

Study these sites then you will have some idea of what to do:

http://www.parktool.com/repair/byregion.asp?catid=53

http://sheldonbrown.com/gearing/index.html

Hi, she has Grip Shift (a twisting part on the handlebars) but i unfortunately i can't tell you any more information at the moment because she is out with her bike, i'll let you know as soon as i can. It seems to just be the chain isn't actuary moving up or down gears when she changes gears...

I don't know the shifter make either, sorry :(