I have often thought about doing this to an old, sturdy road bike. Even top of the line road bikes were alot more solid 30+ years ago, in terms of load capacity maybe equivalent to a current audax or cross bike? Plus old, narrow gauge steel tubing has the flex to absorb added impact. Also, I have never found pinarellos all that special, so this doesn't bother me. Might feel different about a Merckx.
Personally I'd put the weight under the saddle and maybe inside the main triangle.
I have often thought about doing this to an old, sturdy road bike. Even top of the line road bikes were alot more solid 30+ years ago, in terms of load capacity maybe equivalent to a current audax or cross bike? Plus old, narrow gauge steel tubing has the flex to absorb added impact. Also, I have never found pinarellos all that special, so this doesn't bother me. Might feel different about a Merckx.
Personally I'd put the weight under the saddle and maybe inside the main triangle.