Unable to shift to the large cog on my crankset sprockets
 

Heya folks, discovered this forum whilst searching for advice on fixing my bike dilemma.
Basically, my bike refuses to shift the chain to the large cog wheel on my crankset chainrings. The front derailleur looks fine, I think it is moving as it should when i upshift and/or downshift (I think it is, I don't really know what i'm doing when it comes to bicycle repairs and maintenance :<), but the chain isn't moving as it should. The chain is only alternating between the small cog and the middle cog when i shift gears via my front derailleur =/ What's wrong with it, and how do i go about fixing it?

P.S. Not sure if i have the tools to fix it....I just have a screwdriver. I brought an Allen wrench home from london yesterday from my sister's flat, but I can't remember where I put it! >_<

Sounds like you have 2 problems. First is the limit screw adjustment and second is cable tension. Check out Sheldon Browns instructions on how to adjust derailleurs. These instructions can be found by gooing to the link at the top of the first page of this forum area.

This Park Tool repair guide shows adjustments step - by - step.

Since it's so far off adjustment now, it's best if you loosen the cable at the front derailleur clamp, and follow the directions from the beginning. You'll likely need a 5mm hex wrench, and a flat or phillips screwdriver to fit the two small limit screws on the derailleur.

You will need a way to keep the back wheel off the ground while you spin the cranks and shift gears. A helper to hold it, a rope with a loop around the seat, a repair stand, or a car bike rack will work.

The Park Tool instructions start with checking the alignment. Maybe it's been twisted away from a straight line.

Next, the limit screws are set to keep the chain from coming off the chainrings when shifting. Then adjust the cable tension to work with your shifter. Done!

Thanks folks, I'll try them a bit later this afternoon :)

I don't think you have to start from ground zero nor do you need to mess with the limit screws. Once set, a limit screw almost never needs adjustment. If the bike was shifting properly in the past, then your problem is just cable stretch. Shift to the lowest gear and check the cable tautness. If the cable is slack, adjust using the barrel adjusters.

Most all shifting issues can be solved by adjusting the cable alone.

I tried with the barrels and with the screws, but even when i try to shift from the small cog to the middle cog, (1 to 2), the chain does not shift. When i shift to 3 though, the chain switches to the middle cog instead of the large cog. When i shift back down to 2, it stays on the middle cog, and when i shift down to 1, it moves down to the small cog. Any ideas?

www.bicycletutor.com and search for front derailleur adjustment. There's a good video on it.

Sounds like you have to "just start from scratch". That means loosen the cables, shift to smallest front chainring with largest rear cog. Start from there. Make sure the FD cage has enough clearance for the largest chainring.

Think I fixed it :D
The back cassette isn't moving to the smallest (7) cog, but as long as the chainring is shifting from 1, to 2, and to 3, and vice versa, it's a start :) i'll sort out 7 later, but time to take it for a test ride :D It's been a long, lonely 2 months without my bike ;_;

failure to shift to the largest cog on the cassette was the last thing that happened..., before my derailleur cable broke.

maybe 100 miles before...