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Front Derailleur & Shifting Problems

Old 12-12-12, 08:11 PM
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Front Derailleur & Shifting Problems

So i installed a new Crank set on my road bike, and the chain rings are slightly larger then last time (53/39).
The chain was rubbing against the front derailleur so i loosened the cable and the derailleur itself to move it up the bike a little so that the chain was clear from it while on the large ring.

I then tightened the cable up and now im having issues with the chain moving up onto the large chainring, and the derailleur is extremely hard to move with the shifters now... im not entirely sure what i did wrong but it was working perfectly before i installed the new crankest.

Shifters and Front derailleur are Shimano.

Everything is fairly new and clean so its got nothing to do with wear and tear/dirt what so ever.



Appreciate the help thanks.
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Old 12-12-12, 08:19 PM
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https://www.parktool.com/blog/repair-...ur-adjustments
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Old 12-12-12, 09:13 PM
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First be VERY sure that the chain is long enough to allow shifting into the big chainring/big cog combination; try this very gently. You may need a longer chain with the new, larger big chainring. A too-short chain will damage your derailleur and possibly your frame if you forget (and you will) and shift into the big-big combination under power.

Only then:

Follow the Park Tool procedure above from the beginning without skipping any steps. It is very important that you make sure that each step is completed correctly as the following steps depend upon the earlier ones being done right.
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Old 12-12-12, 09:22 PM
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Originally Posted by dsbrantjr
First be VERY sure that the chain is long enough to allow shifting into the big chainring/big cog combination; try this very gently. You may need a longer chain with the new, larger big chainring. A too-short chain will damage your derailleur and possibly your frame if you forget (and you will) and shift into the big-big combination under power.

Only then:

Follow the Park Tool procedure above from the beginning without skipping any steps. It is very important that you make sure that each step is completed correctly as the following steps depend upon the earlier ones being done right.
Thank you, i manually tried the chain on the big chain ring and yes, it is too short for it. Does that mean im going to need a new chain or can i add chain links? if so how do i detemine how many i add?

Also what tools do i need?


These are 8 speed shifters, 8 Speed derailleurs, 8 speed chain
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Old 12-12-12, 09:33 PM
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Odds are that you rotated the FD slightly when you raised it. Thar would throw off all adjustments, including the limits. You may not think so, but it takes only a tiny change in alignment.

With an experienced eye, you might be able to home in on the necessary adjustments, but otherwise I second the idea of starting the setup and adjustments from scratch, including checking the rotation of the FD.
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Old 12-12-12, 10:19 PM
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8-speed chains are relatively inexpensive. Since your chain is now too short I would suggest that you get a new chain which closes with a master link: KMC, SRAM and Wippermann use such links. I do not like the Shimano "special joining pins". You will need a chain tool to shorten the new chain but tools are not needed to close the master link.

I use this method to size chains: https://sheldonbrown.com/derailer-adjustment.html#chain. There is also a "Shimano" and a "Campagnolo" method which use different procedures and have different results. If you have spare links which match your chain you could use master links to add them in.
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