danguskhan

I accidentally bought the wrong front derailleur for a 2x7 to 2x10 conversion I am doing on my 1994 cannondale r400. I got the 105 fd 5700 with some other things I bought off of craigslist. However I got a top pull 34.9 and I need a bottom pull 31.8

Will it work at all to use my old 2x7 derailleur while I wait for the other one to come or is it not going to work at all?

danguskhan

Actually I was wrong, they are both bottom pull. I might actually have a spacer that will let me use this derailleur with my smaller tube. However, if that doesnt work can I use the old rsx 2x7 with my 2x10 or will it not work at all?

Thanks

Retro Grouch 

My philosophy:
If I'm buying parts I'll hold out for the correct matching thing.
If I already own parts I'll bolt up what I have and see if I can make it work.

You're in the second category. I'm about 90% confident that your existing derailleur will work. If you're using bar end shifters or some other friction thing I'd bump that up to about 98%.

Jeff Wills

+1. If you want to try the 10-speed front derailleur, use a short piece of PVC pipe to make a shim. I did this when I bought the wrong size clamp (like you did) and it worked fine for years.