Shifter cables under bottom bracket

[mchaisso]

I just bought a new, used Serotta a few months ago and am now living out my dream of riding one.

One problem is that the cables that route under the bottom bracket were done flush against the paint, and have worn through the paint and now are rusting the frame. Aside from being bad for the frame and paint, it makes shifting really sticky.

How should the cables on an Atlanta be routed? How do you deal with friction?

thanks,
-mark

[regularguy412]

I tried avoiding this same problem with my newly-refurbed-CSI. I tried using some short pieces of cable housing inner liner. The idea was to run them inside the cable guides on the BB and then run the cables inside. However, I found that the cable guides were too small to get the liner through. So I gave up and just routed the cables bare, just like I had done before. My CSI has over 30,000 miles on it and the area under the cables on the BB never rusted. It just has a bit of wear-in where the cables grooved the shell.

The new, thicker paint clear coat, however, made shifting interesting,, just as you have found. Try slackening the cables so they hang free of the guides. You can do this by putting the rear der. in lowest gear next to the spokes and then click the shifter all the way up to top gear. Just don't turn the crank. The der. will move a bit, but then all the extra slack will just hang beneath the downtube. Use a liberal coating of anti-seize _INSIDE_ the guide between the cable and the BB shell. Now turn the crank. The rear der. should carry the chain out to top gear and remove the slack.

Next, do the same for the front der. Push it up to the big ring and then stop turing the crank. Click the shifter and let all the slack hang on the front cable. Lube with anti-seize as mentioned above. Wipe off all excess around the guides.

You may have to re-do this procedure on a regular basis, depending on how much wet and slop you ride through. It has worked for me.

Mike in AR

[samcat]

...will also work and probably last longer. Also, it won't attract dirt.


PH

[dirtdigger88]

...won't attract dirt.


PH

whats wrong with Dirt???

jason

[PoppaWheelie]

These beaded Nokon cables come with a very thin inner liner (not sure if it's Teflon coated) that might be a good solution. Nokon gives you way too much of this when you buy their kit, so you might be able to track some down from a fellow forumite in order to get a inch or so under the BB on each cable. I had a whole bunch, but somehow lost it when we moved a few months ago...

One of Jeff Weir's Sach's photos gave me the idea...looks like the person who did that build did something similar.

[Dave]

Does this frame have permanent, steel cable guides, or the moe common removable plastic cable guide? If it's the later, then first be sure the cable guide is not worn. New ones are readily available from Campy and Shimano.

If the cables touch the BB shell, even with a new cable guide, the problem can be solved with a small piece of polypropylene plastic, placed under the guide to move it further away from the shell. I take a pice of 1 inch black plastic lawn sprinkler tubing and cut a section that's slightly longer than the guide, so it covers the area where the cable rubs. It's flexible enough to conform to the shape of the BB shell. Drill a hole in it for the cable guide bolt, then reinstall the plastic cable guide. A new, longer bolt may be required, but be careful that the bolt does not protrude too far into the BB shell and cause problems by hitting the BB.

[C5 Snowboarder]

This may work also--
Available from McMasterCarr.com - part number below. It will most likely wear a small groove about .015" deep initially and then stop wearing any deeper.

1441T21
Strong and Slippery Adhesive-Backed UHMW Film .042" Thick, 12" X 12"
In stock at $9.83 Each

[mchaisso]

Thanks for all the advice.

Permanent steel cable guides.

Does this frame have permanent, steel cable guides, or the moe common removable plastic cable guide? If it's the later, then first be sure the cable guide is not worn. New ones are readily available from Campy and Shimano.

If the cables touch the BB shell, even with a new cable guide, the problem can be solved with a small piece of polypropylene plastic, placed under the guide to move it further away from the shell. I take a pice of 1 inch black plastic lawn sprinkler tubing and cut a section that's slightly longer than the guide, so it covers the area where the cable rubs. It's flexible enough to conform to the shape of the BB shell. Drill a hole in it for the cable guide bolt, then reinstall the plastic cable guide. A new, longer bolt may be required, but be careful that the bolt does not protrude too far into the BB shell and cause problems by hitting the BB.

[Big Dan]

I usually don't have a problem and one of my Serottas has been around since 92. Once a year you can clean the area, spray some silicone and install good quality cables like DA or Campagnolo. Good luck and enjoy your bike.

[Peter P.]

As I see it, you have a couple choices.

Currently, shifter cables come in two flavors, 5mm and 4mm. I don't know for sure, but perhaps there's a difference in liner dimensions and trying the 4mm variety will fit the bill.

Next, you could try to enlarge the hole. I don't know how much metal is available, but a good hardware store or the McMaster-Carr catalog should have drill bits in machinist's sizes as well as English and metric. You could also try a Dremel tool. I have one, and they have accessory bits come in a wide range of diameters.

If you're timid about the operation, contact Serotta and see what they recommend. I'm sure they've run into this question before.