Weird 90s Rocky Mountain mtb cable routing
 

Hey everyone, I picked up a 1990 rocky mountain project yesterday and having only worked on old road bikes, I'm not clear on all of this new fangled cable routing.

I was told it had all original Deore DX components, which included what appears to be a Deore DX bottom pull front derailleur. What I am confused about is that the braze-ons seem to be for a top mount derailleur. Perhaps that is why it became a project, someone ordered an incorrect part back in the day. Can anyone confirm this?

Let me know if you need better pictures, I think these will work but they're all close up
https://cimg6.ibsrv.net/gimg/bikefor...a4d0241b7b.jpg
https://cimg1.ibsrv.net/gimg/bikefor...4203a7b36d.jpg
https://cimg7.ibsrv.net/gimg/bikefor...e406c741b2.jpg

Is that a threaded hole I see down towards the bottom, on the aft side of the seattube? If so, it was likely fitted with a pulley to run the cable on the top tube, yet still use the bottom pull FDs of the era.

I can't find any pics of one on an old MTB, just CX ones, where they were used for a much longer period of time.

https://cimg0.ibsrv.net/gimg/bikefor...3933b9741c.jpg

I believe you are exactly right, I remember wondering what that weird bit was in the box of parts and I'm fairly sure it was one of those pulleys. I will check in the morning and see if I can get it set up. Thank you!

These ST cable reversing pulleys are a common CX thing a few years ago. As internal cable routing took over the pulleys became a Dodo bird of sorts. Not the best design on a mud intended bike but did alloy bottom pull frt ders to have TT routed cables. Andy

Yep, I had a '92 Trek 7000 MTB and it had the same FD cable routing and the pulley on the seat tube to actuate the bottom pull derailleur with top tube run cables.

https://cimg6.ibsrv.net/gimg/bikefor...93eafa0bca.jpg
Found the bit and installed it (I took it apart and cleaned it after this picture and then threaded it all the way in). The stock shifters even seem to work okay!

Having three sets of cable braze-ons on the top tube and random bits of housing everywhere is a big change from what I'm used to. I think I got the cable positions right with a derailleur cable on each outer braze-on, and the rear brake in the middle.

Close, but the cable is routed wrong at the derailleur pinch bolt.

Under the cable pinch bolt on those derailleurs was generally a washer with a little tab. The cable should go from the pulley, over the tab, then under the pinch bolt. THe tab and cable should both be on the side of the bolt closer to the centreline of the bike.

You are correct although the picture is deceiving, nothing was actually connected at the time. I've since connected it on the inner side. There is only an indent on the rear derailleur for the cable to be clamped into but I will be looking out for a tabbed washer in the parts box just in case. .