TT-DT inside triangle seat clamp

[Amir Avitzur]

What is the frame prep that enables this seat clamp to work?

Amir Avitzur
R"G Israel

[Dan Chambers]

It looks like there's no special prep, just braze the clamp into the corner and cut the slot, probably with a small diameter circular cutter.

The opening into the top tube leaves it exposed to the elements, but my main concern would be the distortion at the seat tub end of the slot. I'd make sure that the seat lug point is long enough that the slot is surrounded by the lug. Also have strain relief holes at the ends of the slots.

There are some fancier arrangements with internal split clamps sections, either through the top tube, or mounted underneath.

They require some accurate milling positioning to get all the parts arranged correctly. The wedge unit sits within a tube which has a hole accessing the side of the seat post. It's a tidy arrangement, but really poor for damage to the seatpost, since there's only a 3-point contact not 360° compression.

All the best,

Dan Chambers

[Alex Meade]

I agree with Dan.  It looks cool, but it has a lot of disadvantages compared to a traditional seat binder arrangement.  I've done it on a stem, picture attached.  Not particularly difficult if you have good machining capability.
Alex

www.alexmeadetools.com