Help for Ghost shifting Drivetrain?
 

The two bikes that I ride the most are my '85 Trek 460 and my '84 Raleigh Portage. They both have Silver Shifters bar end shifters. The Trek shifts as smooth as warm butter, quiet and stays put. The Raleigh ghost shifts and slips under heavy load. What can I do to get the Raleigh to shift as well as my Trek? Is this due to the rear derailers? An adjustment issue? Or something else?

The Raleigh has the stock Deerhead derailers. I swapped out two components on that drivetrain, a 13-32 7 speed freewheel and a 24 tooth granny ring. (Edit to add: also a new chain.) The Trek had the original racing components on it when I bought it from the original owner. I can't get my butt up the hills with racing gears, so I swapped out the Suntour cyclone RD and put on a modern Shimano Deore RD and a 6 speed 13-34 freewheel (and a new chain). It looks goofy, but it works really well.

These are both very large frames -- 25 inch Portage and 25.5 inch Trek. I love the Portage in many ways, but I want to love it even more.

The Raleigh drivetrain:
http://i154.photobucket.com/albums/s...drivetrain.jpg

The Trek drivetrain:
http://i154.photobucket.com/albums/s...drivetrain.jpg

Have you read Sheldon's article (or bit) about ghost shifting? It could be frame flex; one fix may be to take and use cable all the way to the derailler--no exposed wire.

However, you say it "slips". That sounds to me like worn chain. Have you measured the chain stretch? If it is stretched, the freewheel is probably worn out. Or, the freewheel may be worn period.

I remember reading something on the Rivendell site about some generation of those silver shifters having a problem with a plastic bit wearing out. See the description here: http://www.rivbike.com/products/show...end-kit/17-089

Have you taken it apart to see what's up?

Neal