Mountain Biking - Noob post of the day ..

Ok, forgive me. I've yet to master how to adjust derailleurs, which is annoying, really have to get on that. Tried it once and failed never tried again, and now need some emergency adjustment!

Anyways, looking for some quick help

New cogs and chainrings
Derailleur was all adjusted
But must have snagged it
Now it's ever so slightly off, particularly in the middle of the cog
Resulting in chain skipping at the worst of times when under heavy torque

Is there a screw I can slightly adjust to get the middle of the cog workable again?

Seems like when you shift up to the middle of the cog the chain has trouble chaining, it just barely catches which isn't enough to get it to get all the way on the next gear

Picture - The chain SHOULD be on the ring of the cog to the left of which it situated but it half-catches and then falls back and doesnt switch to the next gear like it should..

Can one of those screws beadjusted to get the chain to actually switch to the left?

http://www.bikeforums.net/attachment.php?attachmentid=158255&d=1278258497

158255

On my roadies I use to stand behind the rear cog like in your picture and visually eyeball the chain cog with the drivetrain cog or (cassette) to line the teeth up in adjusting the RD. The FD is just a little this way then that way to get it right while cycling through the front chain rings and through the cassette to find the best optimal adjustment.

Try getting a book on repairs and maintenance like Calvin's with Park Tool. I just picked it up for like $20 and it has great pictures as well as descriptors to tell you how to on many of the most basic and advanced things to be done in bicycle maintenance.

Good luck.

BTW...........there are no noob post to me. Every question is valid and why these forums exist to assist one another. Good luck and let us know how it pans out.

Thanks, I was looking at Park's website but didnt want to undergo messing up my whole gear system just to fix this..can ride it for the time being avoiding that area of the cog but it sucks, yeah, the solution is to figure out how to do this..was hoping there'd be a quick fix because all the derailleur needs to do is move a little to the left and the chain switches easily. Bah

If you stand behind the bike and use the screwdriver and do very small turns you will see the cog go left and right depending on the rotation direction. This will allow you to line it up exact.

Cool I just didnt know which screw does what.

In the pic I'd refer to them as: Top left screw, top right screw, bottom left screw

Dude don't touch those screws. Give the barrel adjuster at the shifter a slight unscrew until it downshifts properly.

If you stand behind the bike and use the screwdriver and do very small turns you will see the cog go left and right depending on the rotation direction. This will allow you to line it up exact.

Erm, you adjust limit screws with the derailleur in the middle of the cassette? Riiiiight...

As above, don't touch those screws just yet. There should be a barrel adjuster on your shifter. According to your description, you want the chain to change to a lower gear. So turn the barrel adjuster about 1/2 a turn anti-clockwise. Click through all your gears and see if it shifts properly. If not, continue adjusting.

It can take a while to get the hang of. The basic rule of thumb is if the chain doesn't shift DOWN (To a LARGER cog, or to the LEFT in your picture) then you need MORE cable tension - Turn barrel adjuster anti-clockwise.

If your chain doesn't shift to a HIGHER gear (To a SMALLER cog, or to the RIGHT of your picture) then you need less cable tension - Turn the barrel adjuster clockwise.

+1 on using the barrel adjuster. Some shifters don't have the barrel adjuster on them though, so you might have to use the one on the RD itself. I had a hard time getting mine adjusted, and finally got it working by tweaking the b-tension, but it's unlikely you'll have to.

The guys are right about the barrel adjuster. It slipped my mind you make minor adjustments with it. It most often fixes your issue with that. My bad for not remembering that.