sheller73

I am currently running a 7800 SS with a 50/34 CD and an 11-28 IRD cassette. I just switched from a 12-27 and dropped the chain twice today. Do I need a GS or am I shifting incorrectly? I was in a bad combo which I should attribute to the first drop but the second I'm not so sure. I know the Campy RD can be rebuilt from SS to SG. Can the DA7800 RDs do the same??

Thanks!

mrvrsick

I'm going to venture out and say it was a front der. problem... but I'm in the search for a cheap pair of bibs/shorts, so that's as far as I'll go

sheller73

Hmmmm... interesting. We shall see... Good luck on your quest for some cheap bibs!

vortexrob

This thread is fascinating. Can you explain the difference between a SS and a GS derailleur? I'm aware of the physical difference between the two, but will the GS permit a wider cassette range: 11-28 than a SS? Or is the GS for a 3 and the SS for a 2?
Thanks.

speedemon

To my knowledge a GS is for a triple

ericm979

GS has a cage that takes up more chain wrap. The SS derailleur can handle up to 29t of wrap, but a 50/34 and 11-28 has 33t. Shimano is conservative with their spec. I know that 31t of wrap works ok, barely. But 33t may cause the chain to be loose in the small ring/smaller cogs (or too tight in the big ring/big cog, which is worse as it destroys the derailleur or frame if you shift there by accident). A lack of chain tension could cause the chain to derail, but I don't think it would cause it to drop off the chainrings during a front derailleur shift.

I use a GS for my bike which runs a 50/34 and 12-27 most of the time but sometimes uses a 12-30.

I don't think you can rebuild an SS into a GS. I have not seen the parts available. But you can use any Shimano RD, even a MTB one. Try adjusting the front deraillur first. The cage should just clear the chain when in the small ring/large cog combo.

sstorkel

What? You didn't like the answer I gave when you posted this same question over in the Touring forum?

sheller73

hahhaa... no Scott, that wasn't it at all... I posted the question in both forums to get both a tourer's and a roadies point of view. Want to get the most info I can from both parties! I will be looking in to both solutions my friend! I didn't have a chain drop at all today. I think it may have been what some call "operator error"???