Hi there.
I have a bunch of old but very servicable bicycle parts as well as
some almost new ones.
I got a cro-moly road racing to build up a bicycle for a friend who
can not afford tp buy one. He really enjoys riding.
The crankset is an old Sugino GT with 34 & 50 teeth rings. The
shifters are Shimano down tube mounted light action SIS but set to
friction mode because the rear gears are an 8 spd SRAM PG850 11-32
teeth cassette. The chain links hacePC 50 stamped on the outer links
and was bought at the same time as the cassette was and used together
for a short time. Both are clean. The rear derailleur is a NOS Shimano
Crane GS with all three springs in new condition tension wise.
Every thing works fine except when a lot of pressure is put on the
drivetrain whilst pedalling uphill whilst seated or standing.
What happens then is that the gear jumps from the 32 teeth cog into a
higher gear but it seems that the chain does not engage properly. This
results in frantic manipulation of the rear shift lever to get the
gear centerd on whatever cog it has landed on before the bicycle loses
all its momentum. This is not so bad albeit very annoying whilst
wearing street shoes. However he wants to try using some look type
pedals that I have and we both fear that this problem will cause him
to crash.
As I said it is a practically new chain and cassette and a NOS rear
derailleur. So what could be causing this problem? The bolt on the
shifter is well tightened and every thing shifts well up and down in
the rear until a lot of pressure is put on the drivetrain whilst
climbing a hill. I used good quality cables and good quality housings
were cut square with a Dremel tool using an cut-off disc.
Thanks from Baffled Peter