Illgot

I'm looking into titanium bikes and want a hybrid hardtail frame built for the road. I'm not finding many hardtails with front derailleur and am curious if there has to be a slot on the frame or does it just clamp on.

Wilfred Laurier

Most front derailleurs are clamped on to the seat tube. However, this is not to say that you can clamp a derailleur on to any bike - the tube may not be round in the area where you intend to clamp, or there may be some other obstruction there (a water bottle boss or suspension mount or something), or the tube may be some exotic thin walled stuff that is not designed to be clamped.

If the tube is round and there is room to mount a derailleur, and you are unsure, contact the manufacturer and ask if the bike is compatible with front derailleurs. I am not specifically familiar with any brands that are not compatible with front derailleurs, but better to ask than to risk crushing your new titanium frame!

There also used to be a style of derailleur attachment that Shimano called 'E-type' that were attached to a plate that was designed to be clamped under one of the (e-type specific) bottom bracket cups. With bikes going to 1X and press fit BBs and other changes in the last decade or so, I don't know if E-type is still an option.

Edit:

Also, not sure what you mean by 'hybrid hardtail' - a 'hybrid' generally refers to a bike with narrower tires and lighter construction than a mountain bike, but more upright position than a road bike. A 'hardtail' is a bike with front suspension but no rear suspension, generally an off-road focussed mountain bike. Technically, many hybrids have rigid frames and some sort of suspension fork, but the name hardtail is usually reserved for mountain bikes.
Also, "29"' wheels found on many modern mountain bikes are the same size as the 700c wheels found on most hybrids, and some have incorrectly commented in the past that 29" wheel bikes are 'just hybrids'.

chas58

Yeah, what he said.
While 1x seems to be the fad these days, some frames are designed differently knowing there will be no derailer. Mostly that applies to mountain bikes, but if the mfg does not offer a 2x option in there catalog- there may be a reason why.

cyccommute 

As Wilfred Laurier said, unless there is something weird about the frame design, the front derailer is just clamped on. Titanium tubes tend to be smaller in diameter than aluminum ones so you’d likely have to use a spacer for most derailers. My 3 have them clamped on. Here’s one

DSCN0934 by Stuart Black, on Flickr
Untitled by Stuart Black, on Flickr