It is also a weakness on small frames. The single layer ov metal tends to stretch under the stresses that headset cups put on the frame resulting in a lower cup that rocks in the frame and a perpetual loose headset condition. This was a real problem with the Trek mountain bikes. Even the 850 used this style lug. I have a small frame Italian Bianchi road bike that uses the same type of one-piece hed lug and has the same problem. If I ever paint it, I am going to pull it off and replace it with a standard 3-piece setup.
Steve Barner, Bolton, Vermont
>I have a Model 1981 MOdel 613 that has such a head tube/lug thing. Looking
>into the head tube, one can see two HUGE holes where the top and down tubes
>attach. They seem to be the size of the ID of the connecting tubes. It is
>cleanly done; very smooth in the inside and I can't tell the difference
>from the outside. However, as was mentioned in a post on another forum,
>one has to wonder about the strength of this thingie in a big frame.