[accidental]

I am building a bike from scatch. This might be a stupid question - but i will ask. I have a frame with a braze-on. Is it possible to mount a clamp-on front derailleur? I dunno if it is possible - i havent bought the component yet.
Also a little diverging - is it possible to use a 9spd crank with 10s group (FD, RD, Cassette)?

 

[C-40]

generally no...

A true braze-on is permanently mounted to the frame and a clamp-on band would fit right where the braze-on is located. Some frames have a "braze-on" that's bolted or riveted to the frame. A bolt-on could be removed easily, but there may still be interference with the riv-nuts in the frame and a clamp-on band.

From all of your basic questions, you better get a good bike mechanic's book or start reading up a www.parktool.com/repair. If you don't know what you're doing, you could make some expensive mistakes.

For the most part, a 9 speed crank will work adequately, but perhaps no perfectly with a 10 speed drivetrain. If you're buying new, get a 10 speed model.

 

[MR_GRUMPY]

"Frame with braze-on FD - can i mount a clamp-on instead?"
.
How much is the frame worth and how much does a braze-on FD cost?
Is it worth screwing up a frame, just to save some money? A one second screw up with a grinder can ruin the frame.

 

[danl1]

Third Way

I am building a bike from scatch. This might be a stupid question - but i will ask. I have a frame with a braze-on. Is it possible to mount a clamp-on front derailleur? I dunno if it is possible - i havent bought the component yet.
Also a little diverging - is it possible to use a 9spd crank with 10s group (FD, RD, Cassette)?

Some clamp-on FD's are identical to braze-ons, up to the point of the clamp connection. That is, the manufacturer makes only one der, and also makes a clamp that performs the same job that the braze-on would. In those cases, it's simply a matter of unbolting the der from the clamp and attaching it to the braze-on instead.