mudboy

I have a Vitus 979 frame. I'm having difficulty finding a decent 1.125" clamp front derailleur that will suit my needs, so I figured I'd just get a braze-on and use an adapter. I have a clamp that should work, but it's loose, so I think the seat tube is actually slightly smaller than normal diameter. Does anyone know of an "endless clamp" type of front derailleur braze-on adapter, sort of like the old SunTour front derailleurs?

Thanks

Pete

Ex Pres 

Sounds like you have Metric/French sized tubing @ 28.0mm vs. "standard" 28.6mm. Is your top tube 26.0mm (vs "standard"25.4mm) as well?
Some manufacturers made these slightly smaller clamp-on FDs back in the day, but it sounds like you're trying to use a more modern set-up.
Wrap some appropriately colored, or clear, vinyl tape around your seat tube.

Jeff Wills

Vinyl tape is probably too squishy for a FD shim. I've used a short piece of PVC pipe to shim a front derailleur- it still works fine after several years.

cmcanulty

For a real skinny shim try a piece of a plastic container or a thin piece of galvanized (less compression but might scratch frame)

cs1

What schedule pipe did you use? Everything I see is way too thick.

Ex Pres 

What I'm suggesting as tape is the kind you would use for a chainstay guard.
Even Sch80 pipe would be too thick, irrigation grade pipe, whatever that stuff is called, might be good for adapting a 1 1/4 to a 1 1/8 or something, but that's just ghetto.

gearbasher

I had an '80 Motobecane w/Vitus tubing and it came stock with an alminum shim that went only half way around the seat tube. It was just on the backside of the clamp. I never had any slipping problems. The bike is long gone, so I can't tell you the thickness of the shim.

mudboy

Yeah, I just measured the seat tube with calipers, and it's 28.1mm, with a French threaded headset (fortunately the frame came with a good Stronglight headset) and a BSC bottom bracket. Freaking French...

I was going to opt to shim it (probably use a soda can), but was looking at my market bike with an old SunTour front derailleur and wondered why nobody made a braze-on front derailleur mount in that style...maybe I'll email the guys at Velo Orange and see if they want to make one.

Thanks,

Pete

Gonzo Bob

Wow. What year is your 979? Mine is from 1986 and uses standard 28.6 FD clamp and has standard 1" ISO headset/fork.

WNG

+1
Your's must be early production?
My Vitus 979 is also ISO fork BSC BB, 25mm seatpost, and takes a 28.6mm FD (Dura Ace mounted on mine).