Thursday, March 24, 2005

Back to the Bluebird: Damn those cables

Back from Chicago, the brakes had arrived. But annoyingly, the tubes and fenders weren’t even shipped from Boston. Some screw up on their end.

I don’t like putting cables on bikes. I never had. I don’t know why. It always takes longer than it should. It’s hard to cut cable housing. And getting the length just right is important.

And I kind of screwed up doing it. "Kind of" because I’ve got to buy more parts and do it again. But only kind of because the bike is functional as is. It’s just not how I want it.

Cable housing is important not to protect the cable (cables can take care of themselves), but rather to provide compression-proof strength. It’s not intuitively obvious to me, but if there was no cable housing, when you squeeze a brake level, nothing would happen.

Think of trying to pull something with string. If there’s slack in the string, and you pull the string an inch, the string just gets a little less slack. To pull, the string or cable has to be tight. But bike cables are never tight, because they have to curve and accommodate the handlebars swinging around.

Road bikes use cable housing at the beginning and end sections and un-housed cable running along the tube lengths, using the frame itself and little welded cable holder to keep everything fixed for the length of the bike. The cable housing serves as a rigid frame which allows the otherwise slack cable to actually pull something.

Here's the rear brake set up on my bianchi road bike:
proper cable setup



Anyway, the first thing I did was cut the shifter cable housing to make it fit the snazzy little cable holder the bike is made for (and had to buy this little piece for the not bargain price of $15).




Then I realized that the whole set up with these components is meant to have the housing run the whole length, which leaves nothing (like the bike not having cable fixtures) to chance. The problem with this intended system is that it doesn’t look good to have cable housing running the length of the bike attached with zip ties, it wastes the nice features of the frame, and the brakes and shifting would probably be more sluggish since the long length of cable housing probably would have some amount of compression in it.

Here's a shot of the bottom bracket cable guide. But it only works for un-housed cable:



The problem with the way I want it is that there is no cable holding fixture on the right side of the chain stay, since these frames aren’t built for internal hub brakes. And the fixture for the derailleur-shifting cable on the left side is positioned for a derailleur and not this kind of shifting hub.



I also didn’t initially see how the rear brake has a built in holder for the housing.


The brake arm is the black piece hanging down kind of on the right. When it pulls forward (left in the picture), the brake activates. The black piece coming out to the left is where both the chain stay attachment and the holder for this special nut that attaches to the bottom of the piece. This special nut then holds the end of the cable housing. (The shiny piece to its left, hanging down from the chainstay, is the brake arm clamp that will have to attached to the same black piece before the brake can work safely.) If you zoom on the picture, you can also see the screw that goes into the drop out. I was actually quite pleased to get a frame that has this feature. This, I have to assume, is designed to make it easy to reinstall the back wheel to just the right position. This is kind of useful because the chain tension has to be just so, not too loose or too tight. And the wheel has to be properly centered in the frame. It's not something you need, but it's kind of nice to have.

By the time I did figure all this out, I had already cut the cable and now it’s too short to reach to the rear hub brake (a much longer distance from the brake handles than the distance to standard rear squeeze brakes).

So I had to order little cable-holding clamps for the chain stays. And new cables (which are cheap). And new housing (which is expensive). That means at least another week for delivery. Sigh.

On the plus side, I did rig up the rear caliper brakes that came with the brake set (I only needed the front brake, but they came as a set). But they’ll go when I get the roller brake connected. And the front brakes are fine, even though the housing needs to be shortened some more. But I want to make sure the handlebars are at the right height before I make the cables too short.

And I put on Zora’s old peddles. There may be a ground-clearance problem with her toe clips if they're facing down when not being used. The peddles are a centimeter or so closer to the ground than on her old bike. But we’ll see. Maybe not. I did buy some new-fangled “power grips” to replace to toe clips. I've never seen them, but they sound cool. And unlike toe clips, they're not rigid.




They may be great, but we may never know as they’re not compatible with Zora’s peddles (which have screws only on one side). So if the toe clips don’t work, then we’ll have to get new peddles.

But as soon as I get some inner tubes installed, the Bluebird will, if not be finished, at least be rideable and ready to go!




The hand grips aren't really on yet either. Everything has to be in place before the hand grips go on for good. They kind of finalize everything as they're a pain to remove and prevent anything else from being replaced.

Maybe I can get some tubes tomorrow just to get the bike on the road. And I ordered a thin cable to lock the seat from dumbasses who would steal it. Of course, a cable isn't a lock. How are you supposed to lock anything with a cable? None of the places that sell “cable locks” explain that dilemma. I guess they would protect quick release items. But thieves around here carry allen wrenches. But some guy in a bike store in Brooklyn told me how a bike chain makes a great lock. They’re strong, and thieves don’t carry chain-link removers. But chains are also heavy and metal. So I use just a few links of bike chain to lock the cable to the seat.



I also hope the Bluebird doesn’t get a lot of flat tires in her rear wheel. With good new tires, she won’t get a lot. But when she does, you have to take off the brake-arm clip and the shifter cable and the brake cable before you can take the wheel off. Kind of a pain. I could get tire liners, but that isn’t part of the fast-bike vision.

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