Originally Posted by
sscyco
I have a 2011 Tarmac SL3 pro with the red group, I replaced the stock cassette with a SRAM red 11-23 cassette. I have roughly 1000 miles on the bike. On Sunday I rode a century and about halfway through I noticed that I could not shift to my lowest gear on the rear. This happens in either of my front chain rings. When I push the lever it will make the shift, but when I release pressure it returns to the next higher gear.
After the ride I put the bike on the stand and played with the low limit screw on the derailleur but there was no change. It seems that the problem has to be in the shifter. It is not holding that gear position. Has anyone here experienced anything like this?
IMO, most likely a cable tension issue. You can check by pulling on the cable with your hand @ the downtube and see that it will shift into the lowest gear. You probably do not want to mess around with the LL screw next time because that could lead to bigger problems.
You can either fine tune by using the barrel adjuster or to get it 100% right...
- Manually shift to the highest gear (small cog) in the rear and small ring in front.
- Untension the cable
- Turn the barrel adjuster all the way in (clockwise) and then unscrew a quarter turn to half a turn (1-2 clicks).
- Retention cable, then fine tune tension by turning the barrel adjuster counter clockwise until desired shifting is met.