I have a SRAM Red Rear Derailleur. I wrecked this weekend in a crit (well twice actually once Saturday and got wrecked Sunday). From the carnage, my rear derailleur was slightly bent. My buddy said he could help, started tinkering with the High and Low tensioner screws, released the derailleur cable etc. And I went from a mostly functional derailleur to one that will not shift into my easiest two cogs in the back.
It shifts smoothly up and down between all the other cogs, but when I shift and the chain gets up the second easiest cog, it slips back down.
I’ve turned the barrel adjuster inward seemingly endless times, Im surprised I am still able to turn it at this point. The cable seems to have the right amount of tension.
Any thoughts here? I am trying to avoid a trip and expense at a LBS while learning something myself.
Turning the barrel ‘inward’ reduces the tension in the cable causing the change to move towards the smaller numerical gears (11t), not the easiest (27T). Have you checked to see if your derailleur hanger is bent? I have landed on my derailleur a few times and it functions properly although I have had to have my hanger aligned and replaced a few times.
Sounds like your hanger is bent. That, or your friend turned the limit screw too much which stops it from going all the way up. Check the hanger first.
Im pretty sure the hanger is bent because when I got back up to ride, when I was in my easiest gear, it was hitting the spokes. I tried bending it back. It looks to be ok now? But then again I have zero mechanical experience. Outside of replacing the derailleur, anything I can do here? I’ve tried physically bending it back.
Ill also try rotaing the barrel outward (away from the wheel) to see if that helps.
Two things…
First, release the tention on the cable and back the limit screws out all the way. basically you are starting fresh. Adjust you High limit and low limit accordingly (might need a trip to the bike spa for that one though, just depends on how skilled you are at fixn’)
Two, check to carbon on the der. I’ve put a crack in mine before. Just as an fyi. In crashes the rear der isn’t always to part that fares the best.
I wouldn’t bother with any other adjustments until you get the hanger back in alignment with the frame. Your LBS can do this in a matter of minutes, but it requires a hanger alignment tool – don’t use the derailleur itself to bend the hanger back in alignment!
I wouldn’t bother with any other adjustments until you get the hanger back in alignment with the frame. Your LBS can do this in a matter of minutes, but it requires a hanger alignment tool – don’t use the derailleur itself to bend the hanger back in alignment!
I hope that advice didn’t come too late. A new hanger costs ~ $20 if the existing one can’t be bent back.
Are you adjusting the right limit screw? There should be a Hi and Low screw. Also, try to post a picture of it here viewing the rear derailer from the very back looking forward.
Remove the rear wheel and confirm that the bolts that fix your rear derailleur hanger to your frame are intact and torqued to proper spec (usually 4-5 nm).
Remove the rear derailleur and use a Park DAG-1 tool (Derailleur Alignment Gauge) to check if your rear derailleur **hanger **is bent out of alignment.
Examine the rear derailleur for physical damage such as being bent, upper guide pulley and lower jockey wheel being out of alignment or limit screws being bent. Part of a SRAM Red rear derailleur is carbon fiber (the outer cage plate) so check that for cracks.
Examine the cogset and verify the cogs are not damaged and that the cogset is still tight on the wheel and the freehub body is functional (ratchets and spins).
Examine the rear derailleur cable, espeically the loop on the right chain stay, to verify it is not damaged.
If no damage is detected reassemble the rear transmission of the bike (wheel, derailleur, etc) and begin by setting the (Shimano vernacular) “B” tension screw and then your limit screws for the appropriate range of derailleur travel across the cogset with the correct stops at the upper and lower limits.
Re-attach the rear derailleur cable verifying that the housing is seated correctly in the barrel adjuster on the derailleur and in the cable housing stop on the frame (if not fully routed internal cables).
Verify appropriate (optimal) cable tension and test the shifting.
This diagnostic should reveal any problems that are compromising your shift accuracy. Also, if you went down- inspect your shifters. I hope that helps.
