Setup new gear cables on 5800 shifters. 6800 rear, 5800 front. (Also have an r8000 front…)
Basically, I can shift the rear cassette into larger cogs. If I try to shift into smaller cogs, there is zero resistance at the shifter. The paddle swings all the way through the range of motion - no engagement. If I let it sit a bit, say 2 minutes, I can shift into those smaller cogs.s
Similar problem in the front.
Internal cable routing? If so, it’s pretty common that cables running in the downtube can get crossed/twisted together during install and it will cause what you are reporting. Other things to check - smooth entry points at the housing (if you cut new housings, make sure you clean them up, grind/file as needed, etc.). The cables are getting hung up somewhere preventing the RD spring to pull the cable back when released by the shifter.
Cables are hanging up on something. Could be bad routing, could be you need to replace housings, could be the guide dirty or broken under the bb. Could be a bent derailleur hanger. Could be limit screws not set properly. Could be cable tension incorrect. Could be a very dirty drivetrain. These are the things I’ve found in the past affecting my shifting. My bike is a 2018 caad12 and there was a service bulletin for the bb cable guide which helped (after my front derailleur cable sawed the crank spindle in half). Other then that, if the drivetrain is sparkly clean and cable tension is correct which I have to adjust about weekly, it shifts pretty well. Di2, étap or externally routed cable bikes are much less finicky!
sounds like cable tension to me… maybe when you fastened the derailleur end, the shifter wasn’t set to the smallest cog/ring. In that case your cable is simply to loose (also too loose to be adjusted with the barrel adjuster). So first, shift to the smallest sprocket/ring, loosen the cable bolt, pull on the cable and fasten again.
If that doesn’t make a difference, check the routing, where the outercables enter your frame or connect to the lugs. (outer cables should be properly seated)
It could be that cable routing and the cables are catching on something. But I had a similar issue on my last bike that had 6700 (10spd ultegra) and it was made worse in the cold (not sure why). When I pressed the small level it just felt like it didn’t ‘catch’. The bike shop I brought it to said its a semi-common issue and I just sprayed some WD-40 into the shifter body and it was fixed.
I’m not sure that’s issue you are experiencing but it might be worth trying before you go chasing cable routing.
I really appreciate all the help - it is not internally routed - external - brand new cables, housing, etc. No bent hangers… The problem seems to be in the shifters.
Talked to my brother, who is constantly buying/selling/upgrading bikes and he gave me that same advice:
Going to try spraying some wd40 in there and see if that resolves it!
So, I soaked down the shifters with WD-40 and almost immediately shifting returned to normal.
Thanks for the help all - it was a weird question to research so I wasn’t sure. All’s well now!
For the next time - one of the ways to diagnose issues like yours is to test the shifter before fully threading the cable through. Keeping the cable in your hand and going through the gears on the shifter will quickly show if it’s working properly or not.
Your issue is quite common on used Shimano brifters, as lubrication dries up in the shifting mechanism. Getting line to the right places is tricky, and this is one of the rare cases where WD-40 is useful in bike maintenance.
Should I flush a spray based lube through after the WD-40? For example I have Pro Link lube in the bigger spray bottle - would a couple of judicious sprays make sense since wd-40 isn’t really a lube?