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Cable guide on a tandem question.(4 posts)

Cable guide on a tandem question.yfoiler
Sep 29, 2002 6:57 PM
I've got a KHS tandem frame I'm going to build up.
On the bottom of the front bottom bracket shell is a welded on tab of 1/8 inch thick aluminum sticking straight down with two 3/32" holes drilled in it. My buddies tandem (same frame) has the bare derailleur cables just lead down the downtube and through these two holes and on back to the deraileurs. I can't believe that this is a good way to route the cables. Bare cable on bare aluminum?...and at that sharp an angle? rub rub rub...
What am I missing here? And more importantly what do I need to do it properly? Grind off the tab, repaint the frame and use a regular plastic guide?

Thanks in advance,
That's pretty much the shandard way it's done on tandems.Spoke Wrench
Sep 30, 2002 5:07 AM
My Santana's that way.

It's not like those cables are constantly sawing back and forth. The actual amount of time that you spend shifting is pretty much negligable, and even then you only move those cables a few millimeters. The tension on shift cables, in absolute terms, isn't very much either. My guess is that cable guide will probably be the last part of your bike to wear out. It's sure to outlast a nylon one. I can't recall ever seeing a shift cable break at that location either and I've been riding and working on tandems for more than 25 years.
That's pretty much the shandard way it's done on tandems.yfoiler
Sep 30, 2002 6:23 AM
Thanks for the info... It's just that with all the "attention" to trick this, and trick that, it comes down to bare cable rubbing on bare aluminum.

From an engineering standpoint it really bugs me that someone doesn't bother to come up with something proper.

re: Cable guide on a tandem question.Lactate Junkie
Oct 1, 2002 9:45 AM
Cut off a 3inch piece of plastic cable liner and slide it over the cable where it goes through the hole. This will give some protection and help things slide easier. It really does not matter much, derailleur cables don't move that much and are under very little tension. It would take decades--maybe more--before the cable did any real damage to the frame