redtzar

Have a 1998 k2 proflex. Deore components. Front deraiiller when shifting, pinches chain against the big ring. What could cause that?

jimc101

Find the part number of the front derailleur, and set up according to the manufactures instructons https://techdocs.shimano.com/techdocs...&bmUID=jR4n2HE should resolve you issue, given the limited info supplied.

redtzar

Right onthanx. What I meant is when I shift from the middle ring to big ring, the chain sticks in between the big ring an derailler cage. Whe I downshift from big ring to small it switches perfectly. Index shifters triple chainring on front. The derailer is bottom pull. Thanks!

Retro Grouch 

It might be a little too low. You should be able to get a penny between the derailleur cage and the longest chainring tooth (if they're not all the same).

cny-bikeman

Any one symptom can have a number of causes. As noted above the first step is to make sure the derailleur is properly set up. Just Google adjust front derailleur and choose the Park Tool or Sheldon Brown links, as well as a multitude of other sources. Once you have followed the entire procedure, including positioning on the seat tube come back here with any remaining problems.

dsbrantjr

Follow this procedure from the beginning, without skipping any steps. Make certain that each step is completed correctly or find out why, since the following steps depend upon the earlier ones being right. If you cannot get a step right, stop and ask here and we will try to help. https://www.parktool.com/blog/repair-...ur-adjustments

There is a link to rear derailleur adjustments there as well, in case you are feeling ambitious.

cny-bikeman

Just realized how old your bike is. A lot of wear can occur to a front derailleur in 15 years. Even if it's not the original the derailleur may have quite a few years on it. Check the left inside surface of the derailleur cage for ridges that may have been cut into it by the chain from repeated shifts. They can keep the chain from shifting up properly. If you see that kind of damage, or if the derailleur pivots exhibit a lot of play replace the derailleur. Also, although that type of wear may result over a long time in any case, it's much more likely if shifts are made under power, rather than with lighter pedal pressure.

redtzar

It Must be old then. I worked on it for 3 hrs. Same result. No matter how high or low. I put it. Proflex is a complete pain in the ass for front derailler adjustment. No matter what it has to come completely off for ANY adjustment at all. Thanks for bell ill figure something out

cny-bikeman

Did you inspect the cage and look for play in the pivots before you worked on it for 3 hrs?

ThermionicScott 

One thing that comes to mind is something applicable to most front derailleurs -- if the cranks and chain are moving at a slow speed when shifting, it's a lot easier to get this sort of a jam. The best way I know to prevent it (once the FD is set up correctly) is to get the pedals moving quickly when you want to shift, and shift to the smaller ring when you see the hill coming, not when you're about to "stall."

redtzar

Hah!! I got it! Moved the cage up it like 5-6mm away from big ring now works flawlessly. Go figure. Took on trail, perfect. Thanks for Advice

cny-bikeman

If you have to adjust something wrong to get it to work, then likely something's still wrong. But it's your ride, so enjoy!

redtzar

Yep im gonna replace it later just needed wheels. Highly suspicious that Itbent. Might as well so ole