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Front Derailleur (SRAM 7) not shifting chain to the big chainring?

997 Views 5 Replies 5 Participants Last post by Critter Cameraman, Dec 31, 2021

Critter Cameraman

Discussion Starter · Dec 30, 2021

Front derailleur issue. SRAM 7 double chainring on a 2013 Specialized Epic Comp. The derailleur was struggling to get the chain up onto the big outer chainring. So, did a complete reset. Screwed shifter barrel clockwise to close to take any added tension out, put chain in small chain ring, unscrew shifter cable clamp at derailleur, centered derailleur cage over chain, turned cranks and ran thru gears to check for chain rub on cage and adjust limit screw as necessary, pull slack out of shifter cable till snug not tight and clamp it down, turn cranks and shift to big outer chain ring (failed)... and the derailleur barely moves 2-3 mm outboard not even making contact with the chain... what did I do wrong?

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Pisgah

· #2 · Dec 30, 2021

You’re derailleur could be getting corroded within the pivots. I had a similar problem a few months ago. I took it to a shop and the mechanic degreased it in a washer. The derailleur improved but the cage later broke. It was an old derailleur. The silver lining was buying a new side-swing, which is a substantial improvement.

You can try replacing the housing too. Grime will make its way into the housing over time, especially bottom pulls.

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J.B. Weld

· #3 · Dec 30, 2021

Critter Cameraman said:
.... pull slack out of shifter cable till snug not tight and clamp it down, turn cranks and shift to big outer chain ring (failed)... and the derailleur barely moves 2-3 mm outboard not even making contact with the chain... what did I do wrong?

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Sounds like a simple case of not enough cable tension. First, set the derailleur is in the small ring position and shift the rear derailleur into the largest cassette cog. Then set the low limit screw so the inside of the derailleur cage just barely clears the chain, maybe 1mm or less gap. When that's all set then pull the cable tension tight at the anchor bolt.

Different front derailleurs and shifters require different cable tensions but it's not uncommon for me to have to set the cable really tight in the position I described and even then often have to add more tension at the barrel adjuster.

Good luck!

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alpinerider38

· #4 · Dec 30, 2021

You could check your high limit screw by moving the derailleur by hand to make sure the limit screw is set correctly or perhaps even over shifting, then set the correct cable tension, and to finish off check it's not over shifting by the high limit screw! Hope this helps👍

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jimPacNW

· #5 · Dec 30, 2021

Also check to be sure the der is not damaged (badly bent or any cracks at the pivots) and relatively straight, I've seen quite a few bent front ders that impeded shifting.
You can also put the bike on a stand if you have one (or have someone hold it up in the air): grab the der by hand and shift to the big gear while turning the crank, - to see if it's the der or the shifter or cable. If the der is badly damaged, front ders should be about the most available of all bike components these days. - Or throw up your hands and buy a single front ring and go 1x!

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Critter Cameraman

Discussion Starter · #6 · Dec 31, 2021

Re-did it all for the umteenth time and then turned the barrel ccw 3 1/4 turns and perfect... I just didn't realize how far the barrel adjuster could move the derailleur. Thanks All I'll get back to you the next time I'm having a stupid ;-P

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