okay, i’ll try to change it up and ask a technical question of the board. i’m replacing my bar-end shifter cable housings and trying to decide how to best route the housings into the cable stops on my downtube.
i use sytace C2 aerobars on a typical Bullhorn set up–no internal routing on the bars or the bike.
currently, the shift housing: 1) exits the dura-ace bar-end shifter, 2) travels beneath the bar tape and along the C2, 3) turns up and over the rear of my bullhorn, and 4) travels down along the headtube into the downtube cable stops. this was the routing schema of the previous owner and seems to put two extra bends in the housing that aren’t necessary, not to mention uses about several more inches of housing.
i’ve looked at pics of the pros, and for those not riding an internally routed set up, they seem to route it along the bottom of the aerobar, but then it doesn’t come up over the rear of the bullhorn. rather it looks like it takes a nose dive right down into the stops.
any advice on this routing and where i should cable-tie it to keep it streamlined and out of the way. obviously i need enough play to steer, but again, i just don’t see the slack on pics of other riders.
thanks…
btw… where can i get a steal on a ouzo pro aero (650c, 1 1/8) or like aero fork ???
Wow, one of my favorite topics. I obsess over customer’s cable routing, length, finishing the ends, etc. Here’s my spin: First off, if you read the installation instructions for Shimano bar-end shifters (SL-BS77) you will see they specify the cables being routed on the outside of the bar but then covered by the “outer casing guide”. The instructions are pretty old school and still assume installation on drop bars (Hello…Shimano!?!), so forget that. One thing though, the darn levers should be installed so the right (rear) shift control shifts DOWN the cogset as you push the lever forward, not upside down like some guys install them. The upside down mounting technique puts the cable in the wrong place, is not “intuitive” (a gas pedal and an airplane throttle speed you up when you prress forward, same with the shifters)and is generally shoddy workmanship. I route the cable under the bar tape at the tip of the aero bar. I always use a little bar tape at the front of the aero bar since your hands are wet and cold after the swim and it is 8:00 a.m and 60 degrees on race morning. Anyway, run it under the tape for about the first six inches, then let it hang down long enough to go to your shifter bosses. Finsih both ends of the housing on a finishing grinder so they are perfectly flat and then throat the housing using a sharpened spoke or other small, sharp, clean pointy tool. Put a good flare on the throat of each end of the cable housing. Shoot some lube in there (Pro Link)and then whipe your inner cable off completely with a CLEAN shop towel. Those things are filthy coming out of the package from Shimano, they NEED to be cleaned off. Put the whole assemly together and use a fourth hand to tug the inner through the housing and “seat” the ends of the housing in the shifter and the shifter boss on the frame. If the inner cable has the slightest “kink” throw it out and use a new one. Be sure you are using genuine Shimano 1.2 mm inners. Once the whole thing is hooked up you can kind of “loop” it up under the aerobars and secure the two cables to one another using a zip ties, keeping the entire cable assembly reasonably out of the boundry layer. At least, that’s how we do it. Good luck!
Thanks Tom. a few comments and questions (if you don’t mind), because i’m a cycletechnophile and love this stuff:
absolutely agree with you on the shifter orientation, forward makes you go faster… makes sense.
“I always use a little bar tape at the front of the aero bar " → do you mean just wrap the bar ends for about 5” or so starting from the tips? sounds like that’s what most people are doing now.
“throat the housing using a sharpened spoke or other small, sharp, clean pointy tool. Put a good flare on the throat of each end of the cable housing. Shoot some lube in there (Pro Link)and then whipe your inner cable off completely with a CLEAN shop towel.” → so you’re saying to widen the opening on one end of the housing, then insert your cable, then squirt a little lube down there, then take the cable out and clean it?
“Once the whole thing is hooked up you can kind of “loop” it up under the aerobars and secure the two cables to one another using a zip ties, keeping the entire cable assembly reasonably out of the boundry layer.” → where along the cables do you tie them together… after they exit the bar tape? and i must admit i don’t know what the boundry layer is.
I’m also assuming i put in just enough slack to let the bar turn about 45 degrees from the middle.
Yup, I wrap about the first six inches with tape and run the cable housing under there. Finish the end of the tape off nice and clean with vinyl tape like the pro cycling teams do.
As for widening the opening: We sent one of our guys to the Barnett Bicycle Academy and when he returned he showed us all how to properly prepare housing for installation. Regardless of the cutters you use (We use Klein Tools or Snap-On) the ends will not be smooth and perfectly prependicular. So, we touch the cable housing ends to a fine grinder wheel to put a nice finish on them- not too long, or it get too hot and melts the vinyl casing, just long enough to make the ends look nice, flat and like jewelry. When you are done with this there is usually some “flashing” or grindings pushed over the cable housing opening. You can open this up using a sharpened spoke or little awl. This puts a little “funnel” opening, very small, so the inner cable transitions smoothly and friction free to the inside of the housing. This is a subtle detail customers never see, but they will feel it, especially when their front derailleur always works well. This is so important on bikes going to course like Ironman Wisconsin- absolutely critical. I’m incredibly anal about this.
Once the correct cable housing has been determined and everything installed the cables usually loop downward from the aerobars. As John Cobb’s wind tunnel tests have shown, every centimeter of exposed cable produces several grams of drag, so it is worthwhile pushing the housing upward so it “hides” along the aerobar then describes an “arc” downward to the shifter bosses. She a photo on one of our Cervelos here: http://www.bikesportmichigan.com/reviews/pk2.shtml
The “boundry layer” is the thin layer of air swirling around the bicycle/rider package as it travels through the wind.
I think you should be able to turn the bars “lock to lock” or all the way through their full range of motion. This facilitates putting the bike in your car, etc. If the bcables are too short and somebody accidently torques your bars all the way around (knocks your bike off the rack in the transition area for instance) it could throw your shifting out of adjustment.
I agree, intuitiveness is a matter of what you are used to. The way that Tom describes, my own preference, is second nature to those of us who grew up with downtube shifters (remember those?)