The Pursuit of Road Bike Perfection; Making Your Road Bike Shift Better and Diagnosing Problems That Can Cause Poor Shifting in Shimano 10 Speed Drivetrains (Tiagra, 105, Ultegra and Dura Ace)

Most people wouldn’t notice that cable housing sticking out a little farther than the other side… I’m not most people.  It drove me nuts!

I wrote yesterday about fixing the rear derailleur shift cable housing that was installed a bit long at the shop because the mechanic was trying to get my system to shift better than I was able to eek out of it when I upgraded the drivetrain from 105 to Ultegra (both 10 speed).

Now, Shimano’s 10 speed system is notorious for running into shifting problems because the rear derailleur’s spring was a little weak.  Searching the internet for help is a struggle in and of itself because there’s a lot out there, but not much is specific.  I can tell you, based on my experience, they fixed the problem with the 11 speed drivetrain – my wife’s 11 speed operates perfectly – and she’s a little harder on her rig than I am on mine, especially on my Specialized Venge.  That bike has only seen two or three raindrops since I bought it new in ’13 (a bit of an under exaggeration, but not by much – I have a very nice rain bike).

I ran into trouble when I bought a used Ultegra 10 speed drivetrain from a friend.  I had a tough time getting the shifting dialed in right after the upgrade… and I had a harder time trying to figure out what went wrong.  After an exhaustive search on the internet, I gave up and took it to the shop.

The shifting was much improved after the shop mechanic had his way with it, but it still wasn’t perfect.  He didn’t like it either, but it was the best he could do.  We blamed it on the idea that the shifters were overused rather than just “used”.  The derailleur had to be dialed in within 1/32 of a turn for the rear derailleur to operate smoothly and (more important) quietly.  Specifically, one of the middle gears would click either going up or coming down the cassette (but not both) if the indexing of the rear derailleur was a little off. It shouldn’t be that difficult to get it dialed in and everything I found on the interwebz said the culprit was drag in cable.  I just couldn’t find it.

Fortunately, on more of a vain note, I hated that the rear shift housing stuck out too far from the frame – it didn’t match the cable on the other side.  I left it that way for a full season because I figured it would be better handled over the winter when I had the time to take it to the shop if I messed something up… better to ride the bike when I can ride it, right?

So, after thinking the process through, I went to work as soon as I had some time after the snow flew.

First things first, I wanted to shorten that cable housing, because doing that gets the shift cable out of the way to really look at how the cable could be getting hung up elsewhere.  For that, I had to pull the rear derailleur cable out far enough that it was inside the housing that leads from the down tube to the handlebar and shift lever so I could snip the housing but not the cable.  This is a simple process for externally routed cables.  For internal cables, it’s a bit more of a big deal.  The problem is running the cable back through the frame.  Mechanics use magnets to feed the cable through the frame – this works especially well with the bike right side up on a stand, as gravity helps, but you can run into problems with some bikes because running new cables requires removing the crank.  To avoid issues, I like using cable liner.  With cable liner, I can run new cable in exactly the same place the old one was when I pulled it – and cable liner, for this purpose, is reusable and cheap.  (Jagwire 1.8mm x 30 meters runs about $11 on Amazon – the 1.8 is a little thicker than others but a shifter cable slides through it more smoothly than the thinner options… the only problem is fitting it into some ferrules/end caps).

So, I did this to trim the housing, but if you’re looking for drag in your shifting system, do the same thing, just don’t snip the housing.  Shift the bike all the way to the small cog on the cassette.  Take the aluminum cable cap off with a pair of needle-nose pliers.  Make sure there are no frayed hairs on the cable tip (give the cable end a quick twist to seat a frayed end if needed) and thread in your first piece of cable liner that you cut long enough it’ll stick out of each hole in your chain stay over the shift cable.  Once your liner is through the chain stay, pull the cable until it’s hanging down from the bottom bracket cable guide.  Unbolt the cable guide cap and remove the small piece of cable liner (if you have one).  Then thread on another pre-cut piece of cable liner that’s long enough to stick out the hole at the bottom bracket and where the cable enters your down tube.  Once it’s through, take two pieces of electrical tape and tape both ends so the liner won’t fall out on you.  Pull the cable through the cable liner.  With the cable out, roll your shifter hood up from the base to expose the hole for the shift cable.  Push on the cable at the housing end until the head of the cable pokes out of your shifter.  Then, carefully pull on the cable head at the shifter until the end of the cable is at the tip of the housing.  Pull the cable another 3″ so it’s well inside the cable housing.  This will ensure that the cable is well inside the housing so you won’t cut it when you trim the cable housing (unless you just want to install a new cable – in that case, pull it all the way out).  Clip the housing and make sure the hole is round.  Put a housing end cap on it and check to see you got the length right – better to cut off too little and have to trim some off than cut too much and have to replace the housing all the way back to the shifter lever.  Push the cable back through until the head is tucked in its hole in your shifter.  Reroute your cable back through the liner in the down tube and pull the liner when it’s through.  If it’ll fit in your system, run a new piece of cable liner at the cable guide underneath the bottom bracket shell (4″ to 6″ will do).  I don’t like leaving bare cable at the cable guide in an internally routed system (the liner in the cable guide limits dirt and thus, cable rot).  Thread your cable through the chain stay liner and when the cable is through, pull the liner and set the two pieces aside to set in a tool box for future use.  Finally, put your derailleur cable housing loop back together and adjust your index your derailleur.

Now, to shifting quality.  In my case a few of the housing ends were coated plastic and when I put everything back together, I noticed the ends weren’t playing well with the barrel adjuster and I didn’t like how the cable slid through the plastic ferrules (end caps) – it just felt like there was a little drag on the cable when I pulled it through the housings.  Drag is bad when you’re talking about a Shimano 10 speed drivetrain because the derailleur spring is too weak.  Any drag, and I mean any, in the system and the rear derailleur won’t work quite right.  I switched the plastic end caps out for metal one’s and put everything back together.  That solved my drag problems in the shifting system.  The shifting went from acceptable to excellent, just like that.  It also survived a double check two nights ago, and a triple check last night.  I can’t believe how smoothly the drivetrain is operating… I’m a little giddy to ride it.  It’s the cat’s pajamas once again.  The problem wasn’t the used shift levers, it was a little bit of drag in the system from something that shouldn’t have been a problem.  Once that was remedied, et voilà

These issues of cable drag in the shifting system can be exceedingly difficult to find and diagnose.  This one was for me.  The shifting quality was excellent on the original 105 10 speed system but over time, the original plastic housing caps ended up gumming up the cable operation.  I had myself stuck in a box with this before, but some elapsed time and forethought, and small problems were not only simple to diagnose, they were easy to fix.

In the end, the shift quality is all about drag in the system.  The less drag, the better the bike will shift.  And sometimes the problem can be as small as a little ferrule at the end of a cable housing that’s gumming the system up – even a cap that worked before a cable change.  A poor cable housing cut can be a problem, too.  Dirty housings, too much or the wrong lube in the housings, old shift levers, dirt or grime in the shift levers, dirt in the derailleur itself… all can contribute to drag in the system and poor shift quality.

When you can’t figure out what the hell is going on, let me recommend reworking the housing system from the shift lever to the back of the bike.  Serfas complete shift cable system that works well and is cost-effective.  It comes with everything you’ll need to change your old cables and housings and it comes with metal ferrules (or end caps).  If you want to go a little next level, Jagwire is fantastic and their pro kit will be a great upgrade for all but the highest-end steed.  Better still, if you want a little more flash, go for the Jagwire Road Elite Link Kit.  Of course, if you just want to stick with Shimano, they make a couple of different grades of cables and housing kits.  The standard and Dura Ace kits.  I have it on authority the Dura Ace kit is supreme, though I’ve never used it (I have the Serfas on my Trek 5200 and a hodgepodge of Jagwire on the Venge).

Finally, for cutting cables and housings alike, I like Park Tool’s cable and housing cutter.  It’s an expensive tool, but worth every penny when you get a crisp, clean cut.  Watch the brake cable housings, though.  They don’t cut as well because of their design and you have to round out the hole before firing a cable through.