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Upgrading from 6-spd SIS to a newer 8-spd STI(4 posts)

Upgrading from 6-spd SIS to a newer 8-spd STILinuxDude
Nov 15, 2002 9:28 PM
I recently acquired a beautiful vintage Bianchi steel road bike from the late '80s. I love the frame ride quality, but don't dig the drivetrain and the down tube shifters (Shimano 600 6-spd SIS). I want to swap its drivetrain with my Specialized AL bike, which has 8-spd STI Shimano 105 components. I know if I do a total swap everything should work, at least on Bianchi. But I would like to keep the lighter (and more beautiful) Shimano 600 Crankset. Do you see any compatibility problems if I go with 600 Crankset (42T/52T,) and 105 for everything else? How would this swap work out for Specialized (Aluminum frame)?

Any kind of help would be greatly appreciated.
re: Upgrading from 6-spd SIS to a newer 8-spd STIRusty Coggs
Nov 16, 2002 4:47 AM
Your rear dropout spacing needs to be 130mm for the 8 speed.Use the rings off the 105 crank for better shifting.The Al frame won't like the narrower hub spacing of the 6 speed hub.
I am in the same boat (long)maximum15
Nov 16, 2002 5:45 AM
Just picked up an '88 Bianchi Trofeo last weekend. I have used it for one Sunday ride and 4 commuting rides. The downtube shifting was awkard with me wobbling each time I shifted. I am getting pretty smooth with the shifting as I get experience and the rear shifting is indexed and works just fine. I think I am going to keep the downtube shifters but am still considering upgrading to 8/9 speed for better gear selection. Sheldon Brown site says you can pay to spread the rear, spread it yourself (with instructions), or just force the 8/9 speed into the rear triangle. I have done the latter as an experiment. No problem and could still shift 7 of the 9 speeds with no problem. BUT, I am concerned that this could cause stress on the axle due to the dropouts not being parallel. I haven't yet decided what to do about this 126mm versus 130mm spacing dilemna but would be interested in the comments of those more knowlegable. One thing I do know -- I can tell why people say steel is real. The ride quality compared to my aluminum Trek 2300 is awesome.
I've done the same...Andy M-S
Nov 16, 2002 2:22 PM
I have a Bianchi Quattro from the same period (c. 1990?). I had an LBS spread the frame and align the dropouts and hanger.

It's currently my main bike, running an 8-speed Sachs Ergo/Shimano mixture. It's about to get a whole lot more mixed next week, when it will recieve a Campy racing triple.

I did 550 miles in 6 days with this bike one week last summer, and it was very comfortable.

As for mixing Ultegra/600/105 stuff, go right ahead. It'll almost certainly work.