UPDATE: Routing Internal Brake Cable on a Pinarello Prince

Like a lot of other bikes with internal cable routing, my new Pinarello Prince has nothing inside the frame to guide its internally routed cables. NOTHING!!! I was frankly incredulous. WTH?

Before we go any further, please note that shifting cable should NEVER, EVER be substituted for brake cable. This could be a fatal mistake. Brake cable is thicker, and made for max strength with much less regard for stretch, while shifting cable is all about minimizing stretch. The cable housings are also completely different.

Note that road brake cable has a round-nose bullet shape, while shifting cable has a barrel shape. If there's any question in your mind, STOP. Get help. This is a serious matter that must be done with certainty.

If there were no factory ends on brake cables many of us would be dead, but it's also the reason you can't just reverse thread cables through the frame and fish them out with a hook. That bullet MUST be anchored in its place in the brake lever in your shifters, and everything that goes over it between those shifters and the front frame port MUST be threaded onto the cable before you fish it though the frame.

STOP! Before going any further, make damned sure you have EVERYTHING you need threaded onto the brake cable, including the housing, metal stop, and plastic frame insert, because once you start winding wire you can't put this stuff on - it's too late and you'll have to start all over!!!

After pulling the fork, which I highly recommend (have a clean plastic container with a lid for the headset so nothing gets lost, and maybe take a pic of the top bearing assembly just in case, but really it's pretty darned simple) if you want to fish the cable out of the top-tube with ease, use a dental mirror and an AAA penlight to see what's in there.

Find some cheap crafting wire, mine was something my wife dragged home from the 99 Cent store, something that is weak and bends easily. You'll need 4-5ft of it. Push the wire through the back hole near the back brake and fish it out of the slot revealed by removing the cable port near the top of the head-tube.

A cable strand is much too hard, but ~ the right size

Wind the wire tightly around the cable with your fingers, with a loose spiral near the end, AND, a very tight wind 2-3" from the end to form a good, solid anchor. Start from the end and wind backwards up the cable. This pattern of winding is important because when you pull on the wire you'll find it'll begin to unwind at the end of the cable in a way that makes the cable end "Hunt" in a circular pattern as it unwinds in a loose cage of spirally wound wire. This forms a kind of sheath that will guide the end of the cable into the slightly flared plastic end which covers the back brake cable port that's embedded in the frame at least once, which is all you need. 

For under $10 you can get a magnetic fish from Lowes Depot Zone, and a lot of other places, but with the fork out you have plenty of room to just use your fingers to guide the wire & the cable through the front fitting cutout. BTW, there is a device made to fish thread out of holes, it's called a crochet needle. Ask grandma. I made a suitable hook years ago out of a piece of metal coat-hanger, but a crochet needle is tailor made for this job.


Now lets talk about the EASY way to thread cable, by slipping it through cable sheathing. Sheathing is really just a guide, and not a structural material meant to bear load when braking, although it can be left in place to stop frame rattles.

If your cable and cable-end is still intact, you can disconnect it from your rear brake and just slip the sheathing over it through the frame, after removing all the housing bits aft of the rear frame port, and the front plastic port insert. Pull as much sheathing as you feel you need and add a foot. You can reuse this hand-crafted tool again and again. Maybe put it in your cable doo-dad drawer/tub with a label so you can distinguish different lengths used for the rear brake from the shifter cables. (the front brake cabling has no interface whatsoever with the frame)

AFAICT these sheathings are the same size

I bought 2 brands of sheathing, JagWire (great stuff) and XmomX (from naughty moms?) I like that you can see the cable when it's inside the XmomX stuff, but just now when I was putting it away it kinked badly. That won't do. If it kinks inside the frame it will not route the cable, so stick with the JagWire IMHO.

BikeTiresDirect had a sale on tools, so I finally gave in and bought a Park Tools cable cutter. Beautiful piece of hardware, and I'm thrilled I don't have to dig out my Dremel tool with a cut-off wheel every time I need to cut cable. As a practical matter, the new Shimano housing melts easily and becomes a bit of a mess when Dremeled. $31 with my Gold membership and 10% of that as a discount on my next purchase.

Sorry for the long delay, but I've been on an annual-mile grudge match with a Strava friend, so I've been putting in 120 - 135 miles a week lately - fueled by Social Security checks. Anyway, thank you for your patience.

Cheers!

Make or Brake

Taking a break from the ATOC for a post, I have been doing a lot of work on my mountain bike, and will be sharing some of my wrenching skills here over the next week or so. Taking time out to make videos and good macro still shots slows things down a lot, but with Sheldon Brown gone I'd like to offer some help to those interested in learning how to maintain their own gear.



Don't be alarmed by my rapid hand motion at the end of the cut. The Dremel is not nearly powerful enough to move your hand out of the way that fast. I was moving my hand to try to prevent the cut-off blade from getting caught and breaking. This doesn't happen very often, but with the light so close and the camera lens to worry about getting showered with sparks it was a bit harder to position myself in the usual way.

Having the use of both hands is also a big help, but if you have a friend to hold the end of the cable and pull on it a bit, and move it slowly so as to open the cut up, it will go very, very smoothly. Just be patient and go slow. If you are doing a lot of cutting (IE: having a re-cabling party with friends) put down an old rug or some cardboard to protect the floor and wear old clothes.

Many, many bikes come assembled with improperly cut cables, being too long or too short, and occasionally, being so poorly cut that it makes brakes and shifters perform poorly. Cables that are too short create kinks, while those that are too long create unnecessary drag and can be a danger for snagging.

Brake cable housing and shifter housing are not the same, and using a shift housing for a brake housing will result in catastrophic failure. This is due to the way the wire is wound, or not wound, as it were, on shifter cables, where the wires run lengthwise from end to end to minimize compression. This makes shift cable much less compressible, but putting a few hundred pounds of load on it will make it burst through the plastic sheathing and leave you without brakes at a really bad moment. Always double check to make sure you are using brake cabling and housing when re-cabling brakes.

Here's a short video showing the simple cutting station I set up with a brief discussion of the important features.



These photographs are from two ends of the same cable. One end I cut off with a Dremel cut-off wheel, and the other is the end the bike shop that sold me the cable made when they cut it off a large spool from the mechanic's bench. As you might imagine, the torn, stretched and cork-screw shaped end from the bike shop will not seat properly, will want to bend and "walk" its way around inside any fitting, turning the cable.

This brake cable would make for very spongy braking with the cable moving around a lot when put under load. If it were a shift cable housing the shifting performance would be very poor, resulting in noisy gears and jumping of gears on the rear dérailleur.



When you cut the actual cable, use some metal duct tape (no, not the plastic stuff, the metal stuff) to wrap the cable with during the cut. You don't want a cable strand coming loose while you cut. The heat of the cut will weld the cable strands together and make a much more durable end. Use the cut-off wheel as a grinding wheel and put a nice dull point on the cable. Again, the heat will weld the cable strands together. It makes for a perfect cut and a cable that will thread perfectly.

I prefer a piece of metal duct tape cut in the shape of a little flag to the little metal ends you get from the bike shop. Squeezing those ends is usually what breaks off a strand, which you don't find out about until you take it off, and then *poof*, you have a frayed cable you'll end up having to replace. If you cut the cable on the frame, which is perfectly acceptable, use something to protect the frame from hot sparks, which will pit paint and carbon fiber clear-coats.

It takes a bit more effort to do this work yourself, but personally, I wouldn't trust something as life and death as brakes to anyone else. Also, I really want my shifting to be as crisp and clean as is humanly possible, so I am happy to do this work myself so I get perfect cabling.