Father2Son

Hello everyone!
I have a question about cable routing on a donated Burley Rock 'n Roll tandem that I'm working on for my bike co-op. The shifter cables are internally routed and come out the back, open end of the down tube. As they exit the down tube, they directly contact the back of the rear bottom bracket shell. Should there be a cable guide to protect the bb shell from the cables? I don't even see any mounting points for a cable guide. It just seems odd to me.

Are there any Burley owners in this forum who can verify if what I'm seeing is correct or if the bike is missing a component? I'm unfamiliar with tandems, and even one of the co-op's senior mechanics, who is an avid tandem enthusiast, is baffled by this cabling situation.

Thanks!

Russ Roth

If I'm remembering mine correctly, the one I had there was a couple of loops under there that the cable just went through and over time they did slightly cut a groove into the frame, the loops kept the cable from moving side to side. I've seen people run sleeves similar to the ones from a V-brake noodle or like the ones used to guide the cable through internal routing through other bikes with the same setup,. But it isn't strictly necessary. Trying to remember if that was the frame I drilled a small hole in the BB shell and tapped it to hold a cable guide, I've now done that with two bikes with little effort.

Father2Son

Thanks Russ,
I'm thinking that maybe tapping the bb shell to accommodate a plastic cable guide would be the way to go if I can manage it.

Are the loops you refer to some type of metal strap on the seat tube that would act as a guide for the cable? If so, I didn't see anything like that on the bike, nor did I see any signs of paint wear indicating a previous installation of any such loop or strap. I'll take a closer look the next time in the shop.

Russ Roth

They were just two little loops of thin wire that wouldn't quite fit a piece of brake housing through on the underside of the BB shell, wire was probably just thicker than a brake cable and they were just to keep the cable from sliding around. I've seen the same thing on other bikes so it isn't just a burley thing.

cyccommute 

Burley did that on many of its tandems. I had a Duet and Samba from the mid 90s and both lacked any kind of cable guide. The cable did wear into the shell on the Duet fairly quickly. My Duet had less than 5000 miles on it but showed significant erosion. Putting on a cable guide would be a good idea. There are some guides that snap into the frame rather than use a bolt. It’s easier to just drill a hole than thread it.

Leisesturm

I don't know. The average tandem simply isn't ridden enough that a shift cable could wear into a BB shell enough to compromise it. I saw where someone used the teflon liner of a brake noodle as sleeving for the under BB shell run of their shift cables. If those couldn't be found, could a couple of 2" lengths of Teflon lined shift cable not serve in that role? I don't see that they would need any 'anchoring'. They aren't going anywhere.

cyccommute 

Mine had cut into the shell at least to the depth of the cable which is from 1.8 to 2.0mm before it hit 5000 miles. That’s only the front derailer. The bike had a steel frame. A length of cable is going to help but installing a guide would be a better option.