Setup issue: front shifting with Serotta Colorado, SM-FC7800 and FC-R700

[jthurow]

I'm moving parts from my Serotta CSI over to a nice Colorado I found. The only difference in the set-ups is that the CSI has the front derailleur mounted via a clamp and the Colorado has a braze-on mount. The problem is that when the crank (FC-700) is mounted via the SM-FC7800 bottom bracket, it is too close to the bottom bracket for the front shifting to work. I couldn't get the front derailleur to shift to the small ring b/c it was hitting the seat tube. It looks like if I shift the crank 5mm away from the shell via spacers in the bottom bracket it will work. My concern is that the non-drive side of the crank have enough purchase on the spindle. Has anyone experienced this sort of thing before?

[cmg]

I'm moving parts from my Serotta CSI over to a nice Colorado I found. The only difference in the set-ups is that the CSI has the front derailleur mounted via a clamp and the Colorado has a braze-on mount. The problem is that when the crank (FC-700) is mounted via the SM-FC7800 bottom bracket, it is too close to the bottom bracket for the front shifting to work. I couldn't get the front derailleur to shift to the small ring b/c it was hitting the seat tube. It looks like if I shift the crank 5mm away from the shell via spacers in the bottom bracket it will work. My concern is that the non-drive side of the crank have enough purchase on the spindle. Has anyone experienced this sort of thing before?

please provide photo of what your trying to do.

[jthurow]

I can do so later since I'm at work. Basically, the front derailleur is too close to the seat tube when it's mounted via the braze on mount. The front derailleur is either a FD-7800 or -7900.

[oldpotatoe]

I'm moving parts from my Serotta CSI over to a nice Colorado I found. The only difference in the set-ups is that the CSI has the front derailleur mounted via a clamp and the Colorado has a braze-on mount. The problem is that when the crank (FC-700) is mounted via the SM-FC7800 bottom bracket, it is too close to the bottom bracket for the front shifting to work. I couldn't get the front derailleur to shift to the small ring b/c it was hitting the seat tube. It looks like if I shift the crank 5mm away from the shell via spacers in the bottom bracket it will work. My concern is that the non-drive side of the crank have enough purchase on the spindle. Has anyone experienced this sort of thing before?

Pretty common on these frames(sold a bunch of them when serotta was a going concern)..WE fixed it, "not enough inward travel of front der", coupled with 'no way to get a longer 'spindle'..hit 'fat' seat tube.....by putting a dent in the tube where the front der hit it..usually a big socket and a sturdy smack fixed it. YMMV and all that. The LH arm on that crank pretty much relies on full insertion to stay on.

[ultraman6970]

What about removing the hanger thingy and use a clamp? I mean, between chop chop and a dent, imo chop chop is better...

[jthurow]

Thanks for the replies. I tried to get pics but the lighting sucks in my basement. I noticed the front derailleur is FD-7800 and the shifters are ST-7900. I was hoping that would make a difference but doesn't sound like it. I'd prefer not to have to dent anything. Maybe I should go old school and be like Lance with one downtube shifter and one STI.

[jtbadge]

7900 shifters need the matching 7900 front derailleur, the cable pull is different from all other STIs.

[Big Dan]

I built my 90's Colorado for a while last year.
Didn't have any issues with my 9 speed FD.
Maybe try a dt shifter up front.