Mishift

FastFly said:

Alright, so I have ultegra rear de. and 105 shifters.

Anyways, I have a hard time going into the biggest cog, I have to hit it twice sometimes, and I cannot go into the smallest. When I shift into the smallest it will only stay for a few revolutions and then jump completely off.

Please ask questions if it will assist people helping me.

Here are the possibilities:
Worn out or damaged chain and or cassette.
Bad derailleur stop settings and maybe B screw.
Bad cable tension.
Cable interference from muck under BB or in housing.
Damaged derailleur and/or derailleur hanger.
Mismatched shifter/cassette gears.
Cross chaining or other operator error.

Check those things out and report back.

DiabloScott said:

Here are the possibilities:
Worn out or damaged chain and or cassette.
Bad derailleur stop settings and maybe B screw.
Bad cable tension.
Cable interference from muck under BB or in housing.
Damaged derailleur and/or derailleur hanger.
Mismatched shifter/cassette gears.
Cross chaining or other operator error.

Check those things out and report back.

Worn out or damaged chain and or cassette. Check
Bad derailleur stop settings and maybe B screw. I dont know how to adjust.
Bad cable tension. Check
Cable interference from muck under BB or in housing. Check
Damaged derailleur and/or derailleur hanger. Scratched but nothing is bent.
Mismatched shifter/cassette gears. Check
Cross chaining or other operator error. Check

How do I adjust stop settings.

http://www.parktool.com/repair_help/FAQrindx.shtml
&
http://sheldonbrown.com/derailer-adjustment.html
&
http://sheldonbrown.com/cables.html
&
http://sheldonbrown.com/chains.html
Look at the chain for wear & the derailer top jockey wheel for too much play. There should be ~1 mm side-to-side movement in the top Jockey Wheel (pulley).

FastFly said:

Alright, so I have ultegra rear de. and 105 shifters.

Anyways, I have a hard time going into the biggest cog, I have to hit it twice sometimes, and I cannot go into the smallest. When I shift into the smallest it will only stay for a few revolutions and then jump completely off.

Please ask questions if it will assist people helping me.

How new is the bike and how recent is the problem?