Older Sram Red rear derailler mounting/spring issue

[54ny77]

Got an older Red derail. on a bike I'm using. The problem is the barrel in which the mounting bolt sits doesn't spring back like it should. Presume there must be some sort of spring inside of that part of the derailleur?

If that description isn't making sense, imagine pulling off the rear wheel and bending back the derailleur to get a little xtra room so the chain frees from the cassette. Once it's out (or once you're putting it back on) and you let go it would normally spring back into place. Well, mine sometimes gets stuck. Or I simply push it back and then it'll have a little bit of spring tension.

I soaked the living daylights out of it with penetrating oil, then doused it with tri flow, and that seemed to have helped. The mounting bolt itself is incredibly tight and barely spins.

Got any ideas on what the cause could be?

None of this affects shifting performance, by the way, as it works just fine. I simply noticed this issue when recently cleaning it up and putting on a new chain.

[Bruce K]

I just had to replace a first generation Force rear derailleur yesterday.

The spring gave out and when in the small ring it would mis-shift and.or jam as there wasn't enough chain tension to keep things working right.

The mechanic and I could not figure out any "fix" to the problem other than replacement.

BK

[54ny77]

Thanks Bruce, this Red derail. is maybe 5 yrs old +/-. Based on the group/bike condition, it didn't get much abuse at all, and is in near perfect condition.

Am wondering if the thing just plain gave out.

Once it snaps back in place it does exert enough spring tension on the chain/pulleys to keep things humming along, but am wondering if it's just a matter of time before it just gives out entirely.

[Kontact]

Got an older Red derail. on a bike I'm using. The problem is the barrel in which the mounting bolt sits doesn't spring back like it should. Presume there must be some sort of spring inside of that part of the derailleur?

If that description isn't making sense, imagine pulling off the rear wheel and bending back the derailleur to get a little xtra room so the chain frees from the cassette. Once it's out (or once you're putting it back on) and you let go it would normally spring back into place. Well, mine sometimes gets stuck. Or I simply push it back and then it'll have a little bit of spring tension.

I soaked the living daylights out of it with penetrating oil, then doused it with tri flow, and that seemed to have helped. The mounting bolt itself is incredibly tight and barely spins.

Got any ideas on what the cause could be?

None of this affects shifting performance, by the way, as it works just fine. I simply noticed this issue when recently cleaning it up and putting on a new chain.
Sram derailleurs don't have a spring under the mounting bolt. That is an old Shimano "servo pantagraph" design that Campy and a few others have copied. The majority of derailleurs ever made do not have a sping in that pivot and do not change angle as you shift. It only needs to change angle when you adjust the angle screw for smaller or larger cassettes.

Your Red derailleur is exactly as designed.

[54ny77]

Thanks for the info. What would cause the mounting bolt to be almost seized? I'm talking about when it's off the bike, by the way, so the issue can't be isolated to anything on the frame (i.e., it's not a derail. hangar issue).

I compared how my derail performs to a buddy's Red (the brand new stuff) and it's night and day in terms of the type of tension I'm referring to. His derail. does not get "stuck" like mine.

Sram derailleurs don't have a spring under the mounting bolt. That is an old Shimano "servo pantagraph" design that Campy and a few others have copied. The majority of derailleurs ever made do not have a sping in that pivot and do not change angle as you shift. It only needs to change angle when you adjust the angle screw for smaller or larger cassettes.

Your Red derailleur is exactly as designed.

[Kontact]

Thanks for the info. What would cause the mounting bolt to be almost seized? I'm talking about when it's off the bike, by the way, so the issue can't be isolated to anything on the frame (i.e., it's not a derail. hangar issue).

I compared how my derail performs to a buddy's Red (the brand new stuff) and it's night and day in terms of the type of tension I'm referring to. His derail. does not get "stuck" like mine.

Any crash marks on the outside edge that could be causing the bolt to bind?

That said, it doesn't really matter as long as everything else is working fine.