[tornadobass]

I was trying to figure out why an early '90s Burley Duet is having shifting problems on the rear derailleur, so I turned the bike upside down. The pair of derailleur cables leave the barcon shifters and go into the down tube. Because it's a 1-piece tube, the cables continue inside until they exit the open tube at the rear bottom bracket.

I was surprised to see that there wasn't a cable guide at the point where the two cables exit. Instead, they just scrape against the tubing, even rubbing against each other a bit. I was expecting something like a nylon piece or a pair or metal braze-on guides to keep the cables separated and off of the metal.

Is this really how it was designed? Or is something missing?

Dan

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[TandemGeek]

I believe that's how it was designed but I've asked someone who should be able to confirm... just haven't heard back from them yet.

[tornadobass]

Thanks...that design allows cables to cross each other or rub against each other, as well as to settle in against the side of the joint where the tube meets the bottom bracket. Seems like it would hang up without some sort of cable guides.

Dan

[TandemGeek]

The collective brain trust that I queried cannot recall there being any braze-ons fitted to the end of the boom tube where the cables exited. Instead, there was a bolt-on plastic cable guide under the bottom bracket -- similar to what is used on 1/2 bikes -- that handled the cable guide duties. http://www.bikesurplus.com/catalog/bottom-bracket-cable-guide.htm

Also similar to 1/2 bikes, the bolt went through the bottom bracket shell and into the bottom bracket to where you had to loosen it to get the bottom bracket out.

[tornadobass]

Mark...thanks for checking around. The screw-on guide would make sense. I couldn't figure out why the cables were just rubbing on the inside of the tube, or why they were wrapped around part of the BB.

BTW, it turned out that I didn't buy that Duet I'd asked about...just returned it this morning. On the second ride, it felt a bit big and I started noticing all the little details that were just a bit out of whack. The costs started adding up for what it would take to get into shape, what it would take to get the add-ons I wanted, and the potential costs if the Suntour components conked out.

I did have a good 30 mile ride yesterday on the Raleigh Companion with my 13-year-old daughter, though. And I spent a bit of time on a friend's RANS Screamer today.

Dan