FD: High-Normal vs. Low-Normal
 

1980 Nishiki road bike. The 2-cog front derailleur is designed and spring loaded in such a way as to return the chain to the LARGE (not small) front chain ring as its detente position . . . i.e. "high-normal." In this way, the rider was able to move the shift levers the same direction to upshift and downshift on both the front and rear mechanisms.

It didn't catch on, and those "High-Normal" FDs aren't seen any more. A look at the photo below may explain why: the FD cage is hopelessly worn - even bent - from years of rubbing. I'm going to change it over to standard "low-normal" setup (no choice, really), but am wondering what challenges I'll run into regarding cable routing, cable stops, etc. The frame is at the paint shop now, so any new cable stops would have to be clamp-ons, IF I can find them. Thanks - here's a pic of the old FD. It's stamped "SunTour" and "Spirt" (not "spirit" or "sprint").

http://bikeforums.net/attachment.php...hmentid=357789

No "challenges". Your shifting just works opposite.
I ruined a high normal (Suntour) when I had a chain break and wrap around the FDER, turning it into a pretzel.
I installed a low end Shimano and it worked fine.

I think the idea was a "good" downshift was considered "more necessary" than an up shift. Pulling cable is more positive than spring tension with a gunked up cable/DER.
"Rapid Rise" RDER's also shift "backwards".

If you use a standard low normal bottom pull front derailleur you will need no additional cable stops, just an under the bottom bracket plastic cable guide. The cable run will be from the shifter (downtube shifter) or housing stop on the downtube (barend or brifter) directly under the bottom bracket shell, through the guide and up behind the seat tube to the derailleur's clamp bolt.

There is no difference in cable stops or routing. High normal required the derailleur spring to do the difficult shift to larger rings, and never worked all that well.

After 34 years anything is bound to get some wear. Frankly, any derailer from 1980 that is even marginally functional is testament to the ruggedness of the part. Wear of the kind that you show could happen to any poorly adjusted derailer.

You should have no problems getting used to the new shift pattern as long as you remember that the two shift levers are going to move in opposite directions.

As for the mechanism itself, the high normal front derailers were brilliant. Far better than the low normal RapidFail...sorry RapidRise...offering from Shimano. In the world of mountain biking, you often are trying to downshift on the crank while under high torque, such as when transitioning from a downhill to a steep uphill. Low normal front derailers need the spring to knock the chain off the larger ring to the smaller one. Often you are left with the chain clattering but not shifting. There just isn't enough tension in the spring to move the chain off the ring. Before the advent of shift pins and ramps, this problem was even worse. So you are stuck with either trying to make the shift under high torque which doesn't happen or with shifting early which has its own set of problems.

The high normal front derailer used the cable to drag the chain off the chainring. This worked brilliantly and made shifting under high torque much easier even before ramps and pins. Think of how the rear derailer works. It drags the chain up the cassette to the lower gears under tension. That's why "RapidRise" was a dumb idea and why Shimano has abandoned it. You don't need the cable to drag the chain to higher gears...that's an easy shift on front or rear.

Ah but grabbing the Low gear on a climb worked well .. As the OP shows, User Ignored scrapes cause wear..

The Engineers keep trying to dummy resistant derailleur systems , but there is always the willful type.

and having a scheme go awry dropping the bike on the right side.