Bicycle Mechanics - Brake cable routing??

As luck would have it, I picked up a white with hot pink trim Cannondale road bike from the early 90's. Full 105, wolber wheels, 12 speed, Aluminum, like new condition (sixty bucks at a yard sale). :D

Ok, thats the good news.

In my quest to make it more "manly", I am replacing the cables and housing. The trouble I am running into is once I have the housing/cable tapped to the drop bars, no matter how I fiddle with it, the back brake cable is getting bound inside the housing. When I have it installed properly (at least what I believe to be proper), it works fine for the first few pulls. Then, I notice some rubbing, then binding, then little or return (It feels like the lever is grinding against itself, if that makes sense).

The calipers are fine and the levers are fine as far as I can tell. I'm not sure if I have a defective cable but the old ones worked fine. I did replace the cable twice and the second generic cable binds less, but the original, which is a larger diameter than the first, binds horribly.

Any suggestions? The only thing I can think of (and mind you , this is the first time I ever replaced cables) is that the routing is not correct, either too long, too short, or to sharp. Or, the housing and cable are somehow defective.

When I have the housing off the bike, the cable runs through it fairly smoothly with little effort. Once on the bike and twisted around, it takes a good deal more effort to get it to pass through.

I looked at Sheldon's site on how to do this, but I guess I've gone wrong?

Thanks,

ehenz

EDIT: I just see where I am supposed to tape the housing while it is under pressure, how vital is that?

Did you de-burr the housing after you cut it? I use a small rat tail file to remove the little sharp piece of metal that invariably is left in the path of the cable when the housing is cut to length. You also might want to put a light film of dry formula Teflon based lube (like Finish Line dry) on the cable before inserting it into the housing. The other thing is to make sure that you are using cables and housing for road bikes, which is different than for MTBs- it is a smaller diameter. If you are using MTB cable in road housing, it might bind up.

Thank you, demoncyclist. I ended up buying new cables and it worked fine (the ones I had were new, but i got them from the worst LBS ever and they must have been 20 years old, or had some defect).

This is an old thread but the topic is on the money and I don't want to ask a question that is a broken record so here we go. A more recent post re FD Ronin suggested looking at Sheldon's site. Wanting to learn I had a read and as usual he is a wealth of knowledge. He had some pics with good and bad cable routing. I further noted his advice which in general was "don't skip the non-sexy stuff like cables!"

Sheldon's Cable basics (http://www.sheldonbrown.com/cables.html) has some pics which I filed away. Today, as I worked on some of the minor details of my Trek 820 restoration for off road use I noted the cable routing before I started to adjust the rear brake to remove play. WHOA! Look at this LBS installed cable! I usually assume all bikes came from the shop optimized but based on what Sheldon says this cable is WAY too long.

Being new to this I thought I would solicit some input. My plan would be to shorten the cable just under the seat post nut and move on. Or is this trivia best left alone? This bike is a platform to learn better wrench skills. The current problem is too much play in rear brakes which is easily adjusted but I thought I might follow the expert and go a little further by improving the cable routing. But not at the risk of screwing up a good LBS assembly!!

Thanks!

Ha, this was an oldie. It is my commuter bike still.

Yes, your plan seems sound to me, and would match mine. I really enjoy making brakes work the best possible.

That is a little more housing than you need from the rear cable braze-on to the brake stop. It should be a slightly gentler curve, ideally coming just over the seatpost nut. Remove the back section of the cable and place the front end in the rear stop on the top tube and then eyeball how much of your cable you will have to trim to get this curve. Best to remove a little less than necessary rather than too much (from your pic, you need only remove about 1 cm or so of cable housing). Clean up the cut ends with a rattail file or a scratch awl so that you don't get any
burrs of the metal cable housing in the cable path.

I just did this very thing on a recent build. It isn't hard.

Just remember, measure three times, then cut in the wrong place.

[Kidding, of course]